Knowledge and Doubt

Higher Philosophy

Knowledge and Doubt

Section 2:

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Knowledge and Doubt

Hume’s Empiricism

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Knowledge and Doubt

David Hume (1711-1776)

David Hume was born in Edinburgh, probably in the family’s home in the Lawnmarket, on 26 April 1711. He attended Edinburgh University at the very early age of 11, and had completed his first great philosophical work by the time he was 25.

At first David was not a very successful academic! He laboured for many years to produce his first book – however it was not successful and did not earn for him the kind of fame and recognition he expected. In an attempt to assist his family’s

finances he took various other forms of employment – but again he was not terribly successful and eventually returned to his first interest. His six-volume history of England made his reputation as an historian.

However it would be wrong to think of Hume as a safe and respectable country gent of the 18th century – he is much more than that. Hume was considered by many of his contemporaries as a dangerous man!

Although the main Arts building of Edinburgh University is named David Hume Tower, the university turned Hume down when in 1745 he applied for a job there. The street in which he lived in the final years of his life is named after him: South Saint David Street, which runs from Princes Street to St Andrew Square (the name is a joke; one of the main reasons why Hume was turned down by the university was that he was notoriously sceptical about religion). Hume is buried in Calton cemetery in Edinburgh, and has recently been commemorated by a statue outside the High Court on the Royal Mile. When Hume died, his close friend Adam Smith – who was also a very eminent philosopher – wrote as his epitaph:

‘Upon the whole, I have always considered him, both in his lifetime and since his death, as approaching as nearly to the idea of a perfectly wise and virtuous man, as perhaps the nature of human frailty will permit.’

Hume has a claim to being one of the most outstanding figures of British philosophy. Not so much because of his influence upon others but simply because of the depth and quality of his work.

Hume is an important figure in the Scottish Enlightenment – an intellectual movement in the 18th century, based mainly in the universities of Aberdeen, Glasgow and Edinburgh. These Scottish cities were referred to as ‘hotbeds of genius’, where men such as Hume carried out ground-breaking work in philosophy – but also in economics, art, law, architecture, medicine, engineering, and science. The Scottish Enlightenment challenged the beliefs of the past, presenting a new way of understanding human beings and their place in the world.

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To a great extent, the social sciences were invented at this time. As we shall see, Hume did important work in what comes to be called psychology; the Kirkcaldy-born Adam Smith is sometimes referred to as ‘the father of economics’, and Adam Ferguson (who was born in Logierait in Perthshire) did pioneering work in what came to be sociology.

The project of the Scottish Enlightenment thinkers is sometimes described as being a ‘Science of Man’. Hume sets out in the text which we are to study – An Enquiry Concerning Human Understanding (1748) – to provide a science of human nature. Hume had earlier stated that his ambition was to be ‘the Newton of the Moral Sciences’. The great English thinker Sir Isaac Newton had, in the previous century, studied natural events such as the motion of the planets and the tides, and had been largely responsible for a new scientific way of understanding the world. Newton had suggested that ‘moral science’ (by which he meant what we would call ‘social science’ – the scientific understanding of man) could be carried out using the same scientific method that Newton had used in carrying out his science. This method – the ‘experimental method’ – is an empiricist method. The starting point for this kind of science is very careful observation. Newton described how physical objects behave; this description was based upon very close study of the ways in which these objects appeared to behave.

Hume’s aim, then, is to discover laws of human perception, desire, feeling, belief, and reasoning.

His starting point is empiricism.

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Knowledge and Doubt

Hume started with this empiricist view. He begins in his Treatise by talking about the perceptions of the human mind – how we know and understand things- and resolved our perceptions down to just two things, impressions and ideas.

Impressions and Ideas

When we began this journey we started by arguing that knowledge is justified, true belief. An enquiry concerning human understanding will, among other things, investigate:

how we come to have the beliefs that we do and will also attempt to answer the question of what beliefs are.

Hume is, therefore, doing what we now call ‘Psychology’.

In order to give an account of the functioning of the mind – of the operation of the human understanding – Hume needs first to give an account of the contents of the mind. All of the mind’s processes – sensing, feeling, reasoning, etc. – have to be about something; some content of the thinking is required.

Hume describes all of these mental contents – all of the contents of thinking or feeling – as ‘perceptions’.

Key Point

If you have studied Psychology, then you will have come across the word ‘perception’. In 21st century Psychology, perception is a process – it is the process of the mind interpreting the results of sensation, such as the vibrations in the eardrum which cause activity in the auditory nerve in the brain – which is interpreted as a particular sound.

It is important to stress that this is not what Hume means by ‘perceptions’. For Hume a perception is an entity and not a process. When Hume talks about perception he is referring to a specific thing, an item in the mind, rather than a set of sensory operations.

Because of the potential for confusion over the word ‘perception’, as Hume uses it, this unit will from now on refer to ‘perception’ in quotation marks, to remind you that it is being used in Hume’s sense, and not in the modern sense.

Activity 1Write a short note on what you understand to be the difference between modern use of the word ‘perception’ and how Hume used it.

Hume opens Section 2 of the Enquiries by making an important distinction:

‘Everyone will readily allow, that there is a considerable difference between the perceptions of the mind, when a man feels the pain of excessive heat, or the pleasure of moderate warmth, and when he afterwards recalls to his memory this sensation, or anticipates it by his imagination.’

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The contrast here is between what is in your mind when, for example, you put your hand into a fire, and what is in your mind when you later remember having done this – or when you merely imagine doing it.

We can try this out for ourselves: imagine, right now, putting your hand in a flame. The experience is not as unpleasant as actually doing it would be – is it?

The same goes for ‘the pleasure of moderate warmth’. Remembering the pleasure of lying on a beach in the Mediterranean, or imagining it just isn’t the same as actually doing it – actually lying on the beach (if it was, holiday companies would be in big trouble).

So Hume has made a distinction between:

Actually experiencing heat and Remembering the heatas pain or pleasure as pain or pleasure –

or even imagining the heat as pain or pleasure.

This is what Hume says about remembering and imagining:

‘These faculties may mimic or copy the perceptions of the senses; but they never can entirely reach the force and vivacity of the original sentiment.’

So we can make various distinctions

1. First we have perceptions arising from our senses.2. The memory of these perceptions is a copy of the original.3. The imagination can provide a weaker recreation of the original.

So:

1. Perceptions arising from the senses are much stronger and more vivid.2. Remembering and imagining perceptions is a much weaker less vivid experience.

So Hume is identifying a difference between perceptions in terms of their force and their vivacity.

What is this difference?

Well, consider two points:

If you burn yourself – you don’t However no matter how well you canneed to make any deliberate recall the pain – it won’t be the sameeffort to feel the pain – the sensation as the original experienceperception is immediate and no matter how you try to re-create the vivid – or dominant and even intensity of the original experience – some time later you don’t it simply is not the same – not as vividhave to make a great effort to or dominant.remember the pain.

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Knowledge and Doubt

So we have more lively and vivacious ‘perceptions’, and less lively and vivacious ‘perceptions’. The less lively and vivacious ones – those which result from the operation of the memory or the imagination – will just never be as lively and vivacious as the ‘perceptions’ of the senses. As Hume puts the point:

‘The utmost we say of them, even when they operate with greatest vigour, is, that they represent their object in so lively a manner, that we could almost say we feel or see it: But, except the mind be disordered by disease or madness, they never can arrive at such a pitch of vivacity, as to render these perceptions altogether undistinguishable.’

It might be that someone who is unbalanced mentally might be able to imagine things with great intensity – including pain. However, even if it is possible for someone who is in that condition to conjure up or hallucinate about experience, and perhaps as a result feel an extreme emotional response, even then would the imagined perception be as strong as ‘the real thing’? ‘The most lively thought,’ Hume suggests, ‘is still inferior to the dullest sensation.’

This is a powerful point – even the most extreme and vivid imaginative event is not equal in intensity to the ‘dullest sensation’. If that is the case, then it marks a clear division between perceptions of real things, and the operations of our imagination.

Hume points out that this applies to every kind of perception. Another example that he gives is of the difference between a man who is feeling anger, and a man who merely imagines being angry.

Activity 2You can try out Hume’s distinction for yourself.

1. Go over to the window of the room that you are in and look at the view outside. As you look, there will be ‘perceptions’ in your mind of the various buildings, people, trees, cars, and so on which are outside.

2. After a few moments, stop looking and go back to your seat. Now call to mind the scene which you have just seen.

What is the difference between the ‘perceptions’ in (1), and those in (2)?

There should be two main differences:

1. While it requires no effort at all to have the visual ‘perceptions’ which you have while looking out of the window (and in fact you cannot will yourself not to see what is there), it does require some effort to call to mind the scene – to have the ‘perceptions’ of the buildings, trees, etc., which memory provides; and

2. Much of the detail which was present in the visual ‘perception’ is absent in the memory-generated perception.

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Exam Prep

According to Hume, how do perception and memory operate? 6 Marks KU

Knowledge and Doubt

Impressions and Ideas II

Hume drew a particular distinction between ideas and impressions which we have already tried to capture. Impressions, he argued were more ‘lively’ more ‘vivid’ than ideas.

Hume labels the two ‘perceptions’ in this way:

Impressions IdeasImpressions are vivid and immediate Ideas are less lively and immediate –‘perceptions’ – which we get from the not as vivid as ‘perceptions’ which weoperations of the senses – and from get from remembering, or imaginingimmediate feelings like anger, pain, things such as pain, smells, soundsjealousy, guilt. and from imagining or remembering

feelings like anger, fear, guilt.

We need to be careful about terminology. An ‘idea’, as Hume uses the term, is what is in the mind whenever I remember something, or imagine something. The idea is the content of that mental operation.

Over time the immediacy and strength of an idea tends to diminish. Things we recall that caused us pain or happiness tend to lose their force. Faces, people, events that were once strong ideas in our minds, gradually fade. Ideas then are things that might vary in clarity and strength, or to the extent to which they carry strong emotional content.

What was in your mind during the earlier experience itself is an impression. Why ‘impression’? What Hume may have in mind is something which was common in the 18th

century, before the development of the modern post office (and before the use of envelopes). When Hume wrote to his friend and fellow philosopher Adam Smith, he had written the letter, and then sealed it. Hume would likely have had his own personal stamp. He would heat a piece of sealing wax, pour it on to the fold on the paper, then put his stamp into the molten wax. This would leave an impression in the wax (which Smith would recognise, on receiving the letter from his friend). The stamp impresses itself in the wax, so that there is now something in the wax which resembles the stamp. Similarly, the world outside the mind impresses itself on the mind when I look at it, or listen to it, etc.

So we take up impressions based on the operation of our senses, which in turn give rise to ideas – memories – of what happened. We burn our hand in the fire, the pain is immediate and vivid – the ‘perception’ gives rise to an impression which in turn gives rise to ideas in our minds which gradually – over time – lose some of their force, but even when these ideas are created they cannot be as vivid and strong as the actual experience was.

There is one final distinction to make. It may seem unimportant – but it will be a very important distinction in later parts of the Enquiry. Hume has identified two different types of impression .

There are impressions such as the impression which I have in my mind when I look at a patch of blue, or taste some red wine, or touch a scrap of velvet, or listen to a passage from Händel, or smell the horse droppings outside in the street. All of these would be familiar impressions to Hume.

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There are other impressions which would also be familiar to Hume: the impression in the mind when I feel disappointment at being rejected for a job, or when I feel happiness at being in the company of friends, or when I feel the pain of toothache.

This might have occurred to you already when we were considering emotions. Some emotions might be responses – some might arise from inside us.

We have, therefore, a distinction between:

Outward Impressions – which arise from Inward Impressions – feelings thatthe operation of the senses. That is they arise inside us, such as guiltbegin with something outside of ourselves or happiness. These feelingshaving an effect upon us. might happen as a result of what Hume

calls the ‘inward sentiments’.

We would nowadays refer to these as ‘External Impressions’ and ‘Internal Impressions’.

Activity 3What do you think about this distinction between ideas in the memory and immediate impressions? Can you call to mind any strong memories that you would consider to be ‘vivid’? Are these memories as strong as what you are at this moment experiencing thorough the senses?

Write a short note describing Hume’s argument about the difference between ideas and impressions and end by indicating what you think of this argument.

Simple and Complex Ideas

Hume recognises the seemingly limitless power of the human imagination:

‘To form monsters, and join incongruous shapes and appearances, costs the imagination no more trouble than to conceive the most natural and familiar objects. And while the body is confined to one planet, along which it creeps with pain and difficulty; the thought can in an instant transport us into the most distant regions of the universe; or even beyond the universe, into the unbounded chaos, where nature is supposed to lie in total confusion.’

The imagination is capable of great creativity, we only have to think about films we have seen, television programs or books we have read which have involved fantastic creations. The creators of Dr Who provide us with a clear example of how ‘the thought can in an instant transport us into the most distant regions of the universe’.

There is just one limitation which Hume recognises here – one thing which the imagination cannot do:

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Exam Prep

Describe how Hume supports his claim that all ideas derive from impressions. 10 Marks

Knowledge and Doubt

‘What never was seen, or heard of, may yet be conceived; nor is any thing beyond the power of thought, except what implies an absolute contradiction.’

An ‘absolute contradiction’ arises where we have both a property and its complete opposite. For example, the following two statements are absolutely contradictory:

The book is red. The book is not red.

If we try to imagine an object that is both completely red and at the same time completely not red, we can’t do it.

Is this the only restriction on the operation of the imagination? Hume thinks not. If we consider how the imagination operates in creating ideas, we will, he suggests, find a very important further limitation on its operation.

Hume identifies four things that the imagination does – four ways in which it can arrive at its ideas:

‘But though our thought seems to possess this unbounded liberty, we shall find, upon a nearer examination, that it is really confined within very narrow limits, and that all this creative power of the mind amounts to no more than the faculty of compounding, transposing, augmenting, or diminishing the materials afforded us by the senses and experience.’

So the four things that imagination can do are:

1. Compounding. Here the imagination takes two or more ideas from the memory, and puts them together to create a new idea. Hume provides two examples of this: The Golden MountainWe have had an impression of a mountain when looking at a mountain, and so have an idea of a mountain in the memory. Similarly, earlier impressions of gold have left an idea of gold in the memory. Imagination can compound these two ideas, arriving at something that I have never actually had an impression of – never seen – a golden mountain.

The Virtuous HorseI have an idea of a horse in my memory – having earlier had impressions of horses. I have an idea of virtue in my memory– having felt virtuous in the past, or having felt good about witnessing your virtue. The imagination can compound these two ideas, arriving at something which is very remote from my actual experience: a virtuous horse.

2. Transposing . To ‘transpose’ is to change the position of a thing. I can imagine the kinds of monsters which are in science fiction films – or classical literature – by transposing the parts of animals on to human beings.

3. Augmenting . To ‘augment’ is to increase. My imagination has no difficulty in arriving at an idea of a mouse which is the size of a tall building, for example.

4. Diminishing is, of course, the opposite of augmenting. I can easily have the idea of a tiny elephant – or of an elephant with a barely audible ‘trumpet’.

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If Hume is right, then we have a complete account of the operation of the imagination.

To see how this account points out an important limitation on the imagination, we need first to reflect on what exactly the imagination is doing.

This argument really means that there are two different kinds of idea:

Simple Ideas Complex IdeasThese are the result of impressions These are made up out of one or morecreating memories – the memory Simple Ideas which have been workedis a copy of the original impression. upon – they have been compounded,These are (as we have seen) less transposed, augmented or diminishedvivid and lively than the original and by the imagination. Complex Ideas are may fade away over time. not simply copies of impressions – as

Simple Ideas are – and may bear littleresemblance to any actual experience.

So from this view of the imagination offered by Hume, we can identify the limits – the boundary that it cannot go beyond. The imagination has to have material to work on – and that material is provided by experience. We can take our previous experiences add them together, mix them up change them around but there is this limit because we cannot put two things together in our imagination that implies a contradiction. The imagination is:

‘Really confined within very narrow limits [because] all this creative power of the mind amounts to no more than the faculty of compounding, transposing, augmenting, or diminishing the materials afforded us by the senses and experience.’

Activity 4Take two or more simple ideas and try out Hume’s set of ways to transform these ideas into complex ideas. Do you think his argument about the limitations of the imagination are accurate?

Write a short note sketching out what you think.

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Exam Prep

According to Hume, how is it possible to imagine something we have never seen? Give examples to support your answer. 6 Marks

Describe Hume’s theory of the “perceptions of the mind” 10 Marks

Knowledge and Doubt

No Innate Ideas!

Read the following passage from Hume (a translation into more modern English is provided on the right):

‘If it happen, from a defect of the organ If someone happens to have athat a man is not susceptible of any defect in one of the senses so species of sensation, we always find that that they cannot experience he is as little susceptible of the something; it follows from that that correspondent ideas. A blind man can such a person cannot understand form no notion of colours; a deaf man of the ideas related to that set ofsounds.’ sensations – a blind man has no

idea of colour – a deaf man no idea of sounds.

‘Restore either of them that sense in which If the blind man gains sight, orhe is deficient; by opening a new inlet for the deaf man his hearing, thenhis sensations. you also open an inlet for not only will they have access tothe ideas; and he finds no difficulty in sensations of sight and hearingconceiving these objects. The case is the for the first time, they will also same if the object proper for exciting any begin to form ideas based on sensation, has never been applied to the these experiencesorgan.’

‘A Laplander or Negro has no notion of the Similarly if someone experiencesrelish of wine ... A man of mild manners something which is unfamiliar orcan form no idea of inveterate revenge or entirely new to them, then they cruelty; not can a selfish heart easily will begin to form ideas based on conceive the heights of friendship and these new sensations. And by the generosity.’ same argument, a person cannot

have ideas about something they have never experienced.

What Hume is suggesting here is that there can be no ideas unless there have earlier been impressions. The man who has been blind from birth will have no idea of the colour blue. The reason for this is, of course, that he has never had an impression of blue. He has never looked at the sky on a clear day, or studied the various shades of blue on the sample cards in a paint shop. Similarly, the Mbuti tribesman in Zaire will have no idea of the taste of Irn Bru; he as never left Zaire, and Irn Bru is not sold there.

During Hume’s lifetime the Americans, who were rebelling against the British, had a slogan: ‘No taxation without representation’. For Hume, we can suggest a slogan:

No ideas without Impressions!

All of our ideas come from experience, on Hume’s account. Every idea is either a simple idea – a copy of an earlier impression which is now in the memory – or it is a complex idea, in which case the imagination has created it, using as raw materials the simple ideas stored in the memory. In either case, every single idea has its origin in experience.

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“But though our thought seems to possess this unbounded liberty, we shall find, upon a nearer examination, that it is really confined within very narrow limits, and that all this creative power of the mind amounts to no more than the faculty of compounding, transposing, augmenting, or diminishing the materials afforded us by the senses and experience. When we think of a golden mountain, we only join two consistent ideas, gold,and mountain, with which we were formerly acquainted. A virtuous horse we can conceive; because, from our own feeling, we can conceive virtue; and this we may unite to the figure and shape of a horse, which is an animal familiar to us. In short, all the materials of thinking are derived either from our outward or inward sentiment: the mixture and composition of these belongs alone to the mind and will. Or, to express myself in philosophical language, all our ideas or more feeble perceptions are copies of our impressions or more lively ones. The idea of God, as meaning an infinitely intelligent, wise, and good Being, arises from reflecting on the operations of our own mind, and augmenting, without limit, those qualities of goodness and wisdom.”

In stating this Hume is clearly putting himself on one side of a long-running debate in philosophy. Many earlier philosophers had argued about the nature of knowledge. The epistemological debate had produced by Hume’s time two strong arguments. On the one hand were those who argued – like Hume – that all knowledge was based on experience, that knowledge was a posteriori – it arose after experience. That there were – in Hume’s terms, no ideas without impressions. However many had argued that there was also innate knowledge. That is the idea that some knowledge was a priori – it arose as a result of the operation of reason alone – prior to and independent of any experiences.

If Hume’s argument is correct, then clearly the case for innate knowledge is overthrown. His argument denies the possibility that knowledge could be innate.

The truth of the empiricist doctrine entails the falsity of the innatist doctrine. That is to say that if it is true that all knowledge and ideas come from experience (as the empiricists claims), then that guarantees the falsity of the claim that some knowledge and some ideas are present in the mind at birth.

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Hume completely rejects the notion that there can be innate ideas. For him the matter is clear, we need do no more than demonstrate that knowledge of things depends upon the operation of the senses, and upon experience, we cannot know things that we have not experienced.

Hume goes on to provide four examples that support his claim that if there has been no impression then there can be no idea.

1. If we have defective sense organs we will not be able to form impressions of certain things. For example, blind men will not be able to imagine colour and deaf men will not be able to imagine sound. “A blind man can form no notion of colours; a deaf man of sounds. Restore either of them that sense in which he is deficient; by opening this new inlet for his sensations, you also open an inlet for the ideas; and he finds no difficulty in conceiving these objects.”

2. Hume then states that the same will problem will arise if we do not have relevant experience to enable us to create ideas from our impressions. “A Laplander or Negro has no notion of the relish of wine. And though there are few or no instances of a like deficiency in the mind, where a person has never felt or is wholly incapable of a sentiment or passion that belongs to his species; yet we find the same observation to take place in a less degree.”

3. Certain personality types are unable to form certain ideas that conflict with their personality. For example if someone is naturally very generous it will be hard for them to become selfish for their own interests and vice versa. “A man of mild manners can form no idea of inveterate revenge or cruelty; nor can a selfish heart easily conceive the heights of friendship and generosity.”

4. Animals have use of other senses that are lacking in us and therefore may have ideas inconceivable to us. For example, snakes are able to taste the air and therefore make up a different picture of the world from us. “It is readily allowed, that other beings may possess many senses of which we can have no conception; because the ideas of them have never been introduced to us in the only manner by which an idea can have access to the mind, to wit, by the actual feeling and sensation.”

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Exam Prep

Explain the arguments Hume uses to support his theory of impressions and ideas. 6 Marks

Knowledge and Doubt

The Missing Shade of Blue

No sooner has Hume emphasised his view that there can be no ideas without impressions, than he appears to contradict himself. There is, he suggests, ‘one contradictory phenomenon, which may prove that it is not absolutely impossible for ideas to arise, independent of their correspondent impressions’. This is the notorious ‘missing shade of blue’ passage. As before, the original is on the left, and a modern translation on the right:

Suppose a person to have enjoyed his Suppose a man of 30 who has sight for 30 years, and to have become has perfectly good eyesight all hisperfectly acquainted with colours of all life has experienced all the kinds except one particular shade of shades of blue – except one.blue, for instance, which it never has beenhis fortune to meet with.

Let all the different shades of that colour, Suppose that we lay out before except that single one, be placed before that man all the shades of blue him, descending gradually from the that he has seen graded from the deepest to the lightest, it is plain that he darkest blue to the lightest – just will perceive a blank, where that shade is by noting that there is a gap wanting, and will be sensible that there is where the shades jump from one a greater distance in that place between the depth of colour to another – contiguous colour than any other. missing out a shade.

Now I ask, whether it be possible for him, Would it be possible for this manfrom his own imagination, to supply this to imagine the missing shade deficiency, and raise up to himself the idea even though he had neverof that particular shade, thought it had never experienced that particularbeen conveyed to him by his senses? shade?

I believe there are few but will be of opinion I believe that most people wouldthat he can … agree that he can …

Earlier on we came up with the slogan based on Hume’s argument:

No ideas without Impressions!

Yet here he is providing us with a ‘contradictory phenomenon’ – a case of just that: an idea without an earlier impression.

Hume responds to this counter-example by dismissing it:

‘… this may serve as a proof that the simple ideas are not always, in every instance, derived from the correspondent impressions; though this instance is so singular, that it is scarcely worth our observing, and does not merit that for it alone we should alter our general maxim.’

In other words, Hume is claiming:

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this is a proof that we can after all have ideas without impressions, but

this case is a one-off, and so:

it isn’t really necessary to take up too much time dealing with it, and

it certainly is not necessary that I should withdraw my earlier claim that there can be no ideas without impressions.

One 20th century commentator, H.A. Pritchard, commented in his book Knowledge and Perception, published in 1950, that:

‘This is, of course, just the kind of fact which should have led Hume to revise his whole theory. It is really effrontery on his part … to ignore an instance so dead against a fundamental doctrine of his own.’

It seems clear that the case of the missing shade of blue is not a one-off; if by some chance the man had heard every note on a piano during his life, except for one, then again his imagination could ‘supply the deficiency’.

The missing shade of blue appears to be a problem because it appears to falsify Hume’s empiricist theory.

Empiricism was defined earlier as the doctrine that all of our knowledge comes from experience, and all of our ideas come from experience.

We can set this out as follows:

P1. If empiricism is true, then there can be no idea which has not come from experience.

P2. The empiricist’s opponent – the innatist – will respond that there are ideas which do not come from experience (innate ideas).

__________C. So that empiricism is false.

Has Hume, with the missing shade of blue, shown the innatist to be right?

One way of redeeming Hume’s position is to ask the question:

Could a blind man’s imagination ‘supply the deficiency’?

The answer is surely that it could not.

Note how the imagination is being referred to here by Hume:

‘I ask, whether it be possible for him, from his own imagination, to supply this deficiency, and raise up to himself the idea of that particular shade, though it had never been conveyed to him by his senses? I believe there are few but will be of opinion that he can …’

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The reference to the imagination is important. Remember that Hume has listed four operations of the imagination:

compounding transposing augmenting diminishing.

This is why the blind man cannot arrive at an idea of the missing shade. There is nothing which he has experienced which he can compound/transpose/augment/diminish in order to gain the idea of the missing shade – because he has never seen any colours at all. The man in Hume’s passage has seen every shade of blue, except for the missing one. At this point, you should be able to work out for yourself how this man succeeds in ‘raising up to himself the idea of that particular shade, though it had never been conveyed to him by his senses’.

The process:

The man has, at various times, an impression of every shade of blue – except for the missing one.

This results in his having an idea of every shade of blue except for that missing shade.

Because he has an idea of every other shade, he has an idea of the shade immediately to the right of the missing shade (the slightly darker one), and of the shade immediately to its left (the slightly lighter one).

By diminishing the slightly darker one he can arrive at the missing shade – and by augmenting the slightly lighter one, he can arrive at the same idea.

So from his experience of the other shades, he arrives at the idea of the missing shade.

So while it is true that neither this man nor the blind man has had experience of the missing shade, and also true that our man’s imagination can ‘supply the deficiency’, this does not show that we can have ideas in the absence of experience (if the blind man could have an idea of the missing shade of blue, then that would pose a big problem for Hume).

So what does the ‘missing shade of blue’ demonstrate?

Think about this.

What is the difference between the idea which the man has of the other shades of blue, and the idea which he has of the missing shade?

What it shows is that colour ideas may be simple ideas, or they may be complex ideas.

Because the idea of the missing shade is arrived at through the operation of the imagination – augmenting and diminishing the neighbouring, simple, ideas – it is a complex idea. If the man had actually seen the missing shade, then the idea of it would be a simple idea – an idea in the memory which faithfully copies an earlier impression.

So the missing shade of blue seems only to show that it is not the case that simple ideas and complex ideas form mutually exclusive classes. For at least some ideas, the same idea can be either simple or complex. Suppose the man later on sees the missing shade of blue –

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gets an impression of it. At that point, he gets a simple idea of what he already has as a complex idea.

Activity 5 – DiscussionWhat do you make of this argument?

In the first case, do you think that you need to have seen every shade of a colour in order to be able to imagine any particular shade?

If you were asked to imagine a dark olive-green with a hint of red – could you imagine that colour?

Try this out with your classmates – can you identify colours that no-one can imagine?

If you can – are these colours that involve contradictory statements? Remember our discussion of imagination previously. Do you think it would be possible to imagine a shade or colour which you have never seen?

What colour would Ultra-Violet be?

Summary

1. The argument about ideas and impressions provided us with the rule that there are no ideas without impressions – which flatly contradicted the Rationalist argument that some knowledge was innate.

2. He then made a distinction between impressions and ideas based upon their impact upon us. Impressions he argued were immediate, vivid, lively in ways that ideas in the mind could not be.

3. In order to explain some elements of the working of the human mind, Hume explored the workings of the imagination. He argued that the imagination worked by:*Compounding *transposing *augmenting *diminishing.

This led to distinguishing between simple ideas – directly recorded from impressions, and complex ideas which were created out of simple ideas by the working of the imagination. So it is possible for us to imagine a gold mountain – or a unicorn – because the imagination works on ideas to compound and create these notions.

2. He went on to refine this argument yet further by suggesting that some ideas were based on impressions from outside of ourselves, but that others could arise from our internal sentiments – or feelings.

3. Hume’s theory seems intuitively obvious and corresponds with a lot of our experiences. He gives us an account of knowledge based on innate faculties rather than innate ideas,

4. In the midst of this argument he mentioned the problem of the Missing Shade Blue – 18

Exam Prep

Outline Hume’s missing shade of blue argument. 6 Marks

Knowledge and Doubt

but dismissed it as a minor difficulty not worth worrying about!

6. He argued that if someone had never experienced a particular form of sensory experience – if someone had never seen colour for example – then they could not form any corresponding ideas that depended upon that experience. Further support to the argument that all ideas are based on impressions.

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Knowledge and Doubt

Hume’s Fork

Up to now we have been concerned with how we come to have ideas – and Hume has given an empiricist account of how this happens. In the next section of the Enquiry, Hume turns his attention to how we come to have knowledge, and again his account is going to be an empiricist one.

To have knowledge is to have justified, true belief.

What is believed is a proposition – such as ‘today is Monday’.

Propositions may be true or false (so that the belief that today is Monday is true if – and only if – today is Monday).

My true belief that today is Monday is justified if I can provide some evidence in support of my claim that today is Monday.

Propositions are, therefore, very important in epistemology. The target for belief – what is believed – is a proposition. The target for knowledge is propositions which are believed, but are also true and justified.

We have already come across a distinction between beliefs which are a priori (and which, if true and justified, are a priori knowledge), and beliefs which are a posteriori (and which, if true and justified, are a posteriori knowledge).

Hume has his own terminology for this distinction.

a priori he refers to as Relations of Ideas a posteriori he refers to as Matters of Fact.

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Relations of Ideas

Hume tells us that a relation of ideas is ‘either intuitively or demonstratively certain’.

Remember that a key question always to ask is: ‘how do you know?’. Hume is here suggesting two ways in which we may come to know some relation of ideas: through intuition, or through demonstration.

The term ‘intuition’ has a particular meaning in philosophy – and this is very different from how it is used by non-philosophers (when, for example, women refer to something which they call ‘female intuition’).

In philosophy, some claim it is intuitive if it is self-evidently true. Think about what ‘self-evident’ means: the claim justifies itself. Here are some examples:

anything that has shape has size either today is Tuesday or it isn’t nothing can be bigger than itself an object cannot be bigger than all of its parts.

With these propositions, we just have to think about them to see that they are true. We just immediately ‘see it’. This is what intuition is (it comes from a Latin word, intuere, which means a kind of intellectual ‘seeing’). Notice how we don’t have to spend any time wondering whether an object can be bigger than the sum of its parts: the truth of this is grasped immediately.

The statement ‘an object cannot be bigger than all of its parts’ comes from the Greek mathematician Euclid. He called statements such as these ‘axioms’. An axiom is a statement where the truth of the statement is grasped by intuition – we ‘intuit’ its truth.

What does it mean to say that an axiom is self-evident? It means that when we are asked: ‘how do you know?’ the answer which we are liable to give is: ‘just think about it’. We do not need to look for further justifying evidence. Anyone who doubts that an object cannot be bigger than all of its parts either isn’t thinking clearly, or doesn’t really know what is meant by the statement. The meaning of an axiom guarantees its truth.

So some relations of ideas are ‘intuitively certain’. But not all are: some relations of ideas are ‘demonstratively certain’.

What makes some claim – some relation of ideas – demonstratively certain is that we can work out, a priori, that it is true (ie. we can establish its truth just by thinking – without the need for observation).

As Hume points out, Geometry, Algebra and Arithmetic deal in knowledge which, if not intuitively certain, is demonstratively certain.

Some claim it is demonstratively certain when it is something which can be worked out using reasoning. An example which may be familiar to you from maths classes is Pythagoras’ theorem: ‘the square on the hypotenuse on a right angled triangle is equal to the sum of the squares of the other two sides’. Pythagoras worked this out a priori. When he was asked ‘how do you know?’, Pythagoras had provided a proof – a piece of reasoning which shows that for any right-angled triangle, it must be the case that the square on the hypotenuse is equal to the sum of the squares of the other two sides. So a theorem is a priori and demonstrative, and an axiom is a priori and intuitive.

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Why call them ‘relations of ideas’?

Relations of Ideas are, like matters of fact, statements. Every statement asserts a relationship between two or more ideas.

If we limit ourselves to statements with only two ideas, then we can see how this works:

(a) The cat sat on the mat.(b) All triangles are three-sided figures.

Statement (a) asserts a relationship between the cat and the mat, while statement (b) asserts a relationship between triangularity and three-sidedness.

Hume suggests that words lack meaning unless they refer to ideas which we can trace to earlier impressions:

‘When we entertain … any suspicion, that a philosophical term is employed without any meaning or idea … we need but enquire, from what impression is that supposed idea derived? And if it be impossible to assign any, this will serve to confirm our suspicion.’

Now if we return to our two statements above, while statement (a) asserts a relationship between the idea of the cat and the idea of the mat, I can only test the statement for truth or falsity (I can only answer the ‘how do you know? question) by checking the world outside of my mind. I have to look at the mat, to see whether the cat really is on it. That makes the statement ‘the cat sat on the mat’ a matter of fact: it is a statement, the truth of which can only be established a posteriori.

Statement (b), on the other hand, requires no such checking of the way the world is. Here the two ideas – triangularity and three-sidedness – are related in such a way that it just has to be the case that anything that is triangular will be three-sided. So a priori reflection on these ideas is all that is needed to establish the truth of the claim. That makes the statement ‘all triangles are three-sided’ a relation of ideas.

Hume later observes, regarding Relations of Ideas, that:

‘Propositions of this kind are discoverable by the mere operation of thought, without dependence on what is anywhere existent in the universe. Though there never were a circle or triangle in nature, the truths demonstrated by Euclid would for ever retain their certainty and evidence.’

Notice how relations of ideas do not depend on how the world happens to be. Even if the world had never existed at all, Pythagoras’ theorem would still be true.

A statement which is true and could not possibly not be false is a necessary truth. The statement ‘no triangular object is circular’ is necessarily true: true, and could not possibly not be false.

Activity 6Consider these statements and think about how you would know them to be true or false.

(a) All swans are white.(b) All bachelors are men.

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(c) The world is round.(d) 2 x 2 = 4.

Write a short note for each one explaining your answer.

Matters of Fact

As we have just seen, relations of ideas ‘are discoverable by the mere operation of thought’. As Hume points out, when we come to consider matters of fact, they are ‘not ascertained in the same manner’.

Consider the following two propositions:

(a) No triangles are circular.(b) Some road signs in the UK are circular.

Proposition (a) here is a relation of ideas. All that I have to do to ascertain the truth of (a) is to think about it. My idea of a triangle, and my idea of a circle are such that it is just impossible for any object to be both triangular and circular. Proposition (a) is necessarily true.

How do I know that proposition (b) is true? If I am asked ‘how do you know that some road signs in the UK are circular?’, I can’t answer by saying ‘well, you just have to think about it’. Someone who had never been to the UK, and had no knowledge of the traffic system of this country just couldn’t work out a priori that we have some circular traffic signs (if you doubt this, try working out, just by thinking about it, what shape the traffic signs are in Venezuela).

The only way to find out what shape traffic signs are in a particular country is empirically. We need to carry out what Hume calls ‘enquiry’. That is, we need to observe – go and have a look at traffic signs, or ask someone who has done this and is therefore a reliable authority, or check in an authoritative book such as the Highway Code, and so on.

Note how we can tell, just by thinking about it, that Venezuela does not have traffic signs which are both circular and triangular at the same time. That is necessarily the case (it is a relation of ideas).

Note also that if Venezuela does not have circular traffic signs, we can say that it could have had them (contrast: Venezuela could not possibly have signs which were both circular and triangular at the same time).

The way that we put this point is to say that ‘some traffic signs in the UK are circular’ is a proposition which is contingently true.

So matters of fact are a posteriori, and contingent. Relations of Ideas are a priori and necessary.

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Exam Prep

Give three examples of what Hume might regard as “Relation of Ideas” 3 Marks

Knowledge and Doubt

There is a test for deciding whether any proposition is a relation of ideas or a matter of fact. Hume points out that:

‘The contrary of every matter of fact is still possible; because it can never imply a contradiction, and is conceived by the mind with the same facility and distinctness, as if ever so conformable to reality.’

What he means by this is that if we take any proposition which is a relation of ideas – such as ‘no triangles are circular’ – the opposite (‘the contrary’) of this proposition is self-contradictory:

‘some triangles are circular’ ‘all triangles are circular’.

are propositions which contradict themselves.

Notice how there is also a psychological test. Our minds cannot conceive any object being both triangular and circular at the same time. A triangular circle is just inconceivable.

With matters of fact, by contrast, the contrary is not self-contradictory. If we say:

‘no traffic signs in the UK are circular’

then we say something that is false – but we have not contradicted ourselves. Because it is only contingently true that some UK traffic signs are circular, the world could have been such that no UK traffic signs are circular (that, of course, is why we have to use empirical means – observation – to find out one way or the other).

Note also that when we come to the psychological criterion – the ‘conceivability in the mind’ criterion – it is in fact easy to conceive of a situation in which there are no circular UK traffic signs (where, for example, the Department of Transport redesigns traffic signs, so that there are no longer any circular signs).

Activity 7Looking back over the arguments that Hume has presented about the nature of knowledge, where do you think we now stand? Has Hume persuaded us that innate knowledge does not exist? Do we better understand how our minds work on sensory information to create complex ideas? Hume has argued that there are no ideas without impressions – is he correct? Look back over your notes and try to summarise where we have go to, then try to give your view about his arguments.

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Exam Prep

What does Hume mean by “Matters of Fact”? 3 Marks

Explain the purpose of Hume’s Fork. 8 Marks

Knowledge and Doubt

Habits of Thinking - Causation

When Hume turned to considering the meaning of some phrases, terms and statements used by philosophers, he found that they did not hold up in terms of his own established rule: Only those ideas that are based upon impressions are real. When he considered certain statements in the light of that rule, he found that they simply evaporated. What did it mean for example, to claim as some philosophers had – that there was a ‘substance’ within things that was essential to them, when there was no impression upon which to base this claim?

Now that might mean that all sorts of statements and terms used by philosophers could be called into question – but that was not a terribly important matter after all philosophers had been arguing about such matters for a very long time. However there are other important implications that arise from this perspective. For example what did it mean to state that one thing ‘caused’ another? Was there an impression upon which the idea of cause was based?

In a famous discussion Hume offers us the example of a billiard table. Think of the simple process – the cue strikes the white ball, it rolls across the table and strikes a red ball and the red ball rolls in turn off towards a pocket. We would happily say that the reason for the movement of the red ball was the impact it took from the white ball. Being struck caused the red ball to move.

In order to explore this Hume invites us to think in strict empirical terms. What can we record about these events as impressions? In the first case in order for these events to take place, the red and the white ball need to be close to each other, they have to occupy more-or-less the same

space. They both need to be on the same table. So first of all we can record that we need a relationship in space between the objects concerned and that is something we can note and understand as an impression. Secondly one ball has to move first, the other second, so we also need a relationship in time. Again this is something we can observe and note – it is empirically established.

If we now want to claim that the movement of the red ball caused the movement of the white, we are in some degree of trouble. In effect when we observe a chain of events such watching one billiard ball strike another we want to identify three sets of relations.

1. Relations in space.2. Relations in time.3. A necessary connection or relation between one thing and another.

The first two we can demonstrate empirically, we can observe the relations in time and space. The last however we cannot observe empirically – or to put it in Hume’s terms – there is no impression to support this idea.

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That being the case, and using the rule that Hume has established, if there is no impression, then there is no reality to the idea. Hume has undermined the whole idea of causality.

Think of it another way. We put the key in the car’s ignition and turn it on. Each time we do this there is a clearly perceivable set of processes involving relations in time and space. When we turn the key can we know that the car will start? Again the answer has to be no. There is no impression that tells us that events in the past prove what will happen in the future. Perhaps for the most part the car does start, but sometimes it does not – and since there is no necessary connection between events in the past and events in the future we should in a sense be as surprised when it does start, as we sometimes are when it does not!

The fact that we are surprised perhaps indicates something important about how we think. We like to imagine that our world works in a predictable way, we like to think that we know that events are tied together by cause and effect, but in truth these are – what Hume describes as – merely habits of thinking.

You may be familiar, if you have studied Psychology, with the famous experiment usually referred to as ‘Pavlov’s Dogs’. The Soviet scientist Pavlov showed that he could – by repetition and custom – establish a pattern of behaviour in dogs. Each time the dogs were fed a bell was rung. After some repetition of this practice, the bell only had to be rung for the dogs to salivate in anticipation.

Did the bell ‘cause’ the food to appear? Clearly not – but the repetition of the practice had established for the dogs a pattern, a sequence of event. The two things occurred together, the ringing of the bell and the provision of food. This is just like – in a sense – the repeated experience of turning the key in the ignition and starting the car. In both cases a set of things occur together, which we associate. Or as Hume puts it we establish in our minds a ‘constant conjunction’ and having established this we expect the same pattern to repeat under the same or at least similar conditions. However we have no evidence, no empirical basis for thinking in that way all we have is a habit of thinking acquired over time – just like Pavlov’s dogs although in the case of the dogs it is unlikely that they assume that this proves that cause effect is involved!

This means that our belief in necessary connections is based on custom and habit, rather than any deductive reasoning processes. This is not scientific nor intellectual. Therefore our belief in the laws of cause and effect and causal laws is actually irrational! However, we cannot help inferring causes when we are habituated by observing constant conjunctions of events. This demonstrates that the role of reason is in fact very overstated, which supports the empiricist agenda that all knowledge is based in some way on experience.

Activity 8Summarise in your own words the problem that Hume has identified with the idea of causality.

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Part 2 – The Foundation of Conclusions from Experience

‘What is the nature of our reasoning concerning matter of fact? the proper answer seems to be that they are founded on the relation of cause and effect. When we ask What is the foundation of our understanding of cause and effect? it may be replied, Experience’

We base our knowledge of future events in past experience, but how do we know that the past is a good guide for future predictions? Hume distinguishes between "demonstrative reasoning," which is based on relations of ideas, and "moral reasoning," which is based on matters of fact. We cannot know that the future will resemble the past by means of demonstrative reasoning, since there is no contradiction in suggesting that the future will not resemble the past. Moral reasoning is also unhelpful, since it falls into a vicious circle. If all our predictions about the future are based on this principle--that the future will resemble the past--and that principle is derived from past experience, we cannot know that it will remain true in the future except by assuming that principle from the outset.

Hume suggests that we infer similarities between past and future but that there is no form of reasoning that can confirm these inferences. He confesses that he may simply have failed to identify an argument that could give a rational foundation for causal reasoning, but he challenges the reader to identify it. Even a child knows from past experience that a flame will burn. If this knowledge comes from some form of reasoning, it must be a form of reasoning so obvious that even a child can grasp it. Why, then, Hume asks, is it so difficult to identify? He suggests that the child learns, not through reasoning, but through the conditioning of custom.

This means that our belief in necessary connections is based on custom and habit, rather than any deductive reasoning processes. This is not scientific nor intellectual. Therefore our belief in the laws of cause and effect and causal laws is actually irrational! However, we cannot help inferring causes when we are habituated by observing constant conjunctions of events. This demonstrates that the role of reason is in fact very overstated, which supports the empiricist agenda that all knowledge is based in some way on experience.

Hume explains this process by referring to animals:

“It is impossible, that this inference of the animal can be founded on any process of argument or reasoning, by which he concludes, that like events must follow like objects, and that the course of nature will always be regular in its operations.... Animals, therefore are not guided in these inferences by reasoning: neither are children; neither are the generality of mankind, in their ordinary actions and conclusions... Nature must have provided some other principle, more ready, and more general use and application; nor can an operation of such immense consequence in life, as that of inferring effects from causes, be trusted to the uncertain process of reasoning and argumentation.”

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Exam prep

Why does Hume conclude that our belief in causal connections is not rationally justified? 8 Marks

How does Hume’s discussion of animals in section IX of the enquiries support his view that causal connections are not rationally justified? 8 Marks

Do you think Hume’s discussion of animals is successful in strengthening his position on the nature of causal reasoning? 14 Marks.

Knowledge and Doubt

The Problem of Induction

The Princess (Robin Wright) in Rob Reiner’s (film) The Princess Bride (1987) is sure that she and her dashing rescuer Westly (Cary Elwes), on the run from the unpleasant Prince, will never survive the dreaded Fire Swamp. But Westly’s response shows the right degree of caution about inductive inferences, no matter how strongly based: ‘Nonsense, you’re only saying that because no one ever has.’

Philosophy Goes to the MoviesChristopher Falzon (Routledge 2002)

This is what has come to be called the Problem of Induction. Induction is the process of reasoning from past examples, because we know, or rather assume, that fire is hot, we do not put our hands into the flames. Past experience has taught us this and from that past experience we reason that under similar conditions, the same things will occur, that is induction. Importantly induction is a key element of scientific reasoning. Whenever we carry out an experiment in science we are operating inductively, we are assuming that what is true for one experiment in the past will hold true for other experiments in the future. Hume however has posed a real problem here, science is based on learning from experience, in other words it is empirical, Hume has taken that empiricism to its logical conclusion to the point where it becomes clear that inductive reasoning does not stand up to an empirical analysis.

Hume gives a further clear argument to support the idea that we are creatures that depend upon habits of thinking. If we were to compare the behaviour of people to that of animals – what lessons could be learned?

In the first case, is it not the case that in many respects the behaviour of an animal and that of a person will be remarkably similar? For example a dog will seek to avoid being burnt by a fire as much as a person would. If a dog comes upon a precipice it backs away – just a person would. People and animals tend to avoid pain and seek out pleasure. That being the case why should we assume that the reasoning of animals is in this at least, any different from our own?

This must make us conclude that arguments about the special nature of the human mind are less than convincing. For much of the time, humans would do little different from animals, and so for the most part the operations of the animal mind and the human mind must be very similar. Animals will base their actions and reasoning upon impressions – just as we do. Repeated or customary events in the life of the dog will set up customary practices and behaviours. By the same token our beliefs as to the nature of our life cannot be immune to effects of custom. The dog hears its master call it to be fed; does it construe from this cause and effect? Does it believe that there is a necessary connection between being called and being fed? No – it simply acts on the basis that that is what usually happens. We on the other hand have sets of events in our lives that seem to repeat and we behave accordingly. Custom and practice lay down patterns for our life. But that does not mean that we can leap to the conclusion that something else we call ‘cause and effect’ is involved. Habits of thinking are part of our nature.

In effect then Hume has given us two strong arguments against induction. One psychological – we mistake constant conjunction for cause and effect because it suits our

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habits of thinking – and one logical – for induction to work there would need to be a necessary connection between things that does not in fact exist.

One way of understanding this argument is to take the view that Hume has thoroughly undermined the basis of science and has a very strange view of the world. He seems to live in a world where cause and effect does not work and nothing we have done in the past establishes what will happen in the future. How does he live and work if that is the case? In fact of course, Hume behaved as we all do as if experiences in our past told us what would happen in the future. He did not have to put his hand into the fire every time he saw a fire in order to be sure that it would burn him!

So another way of understanding his argument is to appreciate that he is saying that this is the reality of where we are. We operate by these ‘habits of thinking’ and that is what we must do. Hume himself seemed to swing between a rather depressed view that whenever we tried to establish our habits on a more sure foundation we were doomed to failure to a rather carefree view that – well, at the end of the day we had no option really but to carry on as if our habits of thinking were absolutely right and fine, so why worry?

Summary: Section 4 – Part 1 (necessary connection between cause and effect) and Part 2 (conclusions from experience)

Hume’s fork. Hume suggested that knowledge split or divided (hence the idea of a fork’) into two forms, Matters of Fact and Relations of Ideas. He used the term a priori to mean relations of ideas, and a posteriori to mean Matters of Fact. Relations of ideas provide certainty because they are either intuitively or demonstrably true. Matters of fact however are contingency true.

Hume then asked us to appreciate that our view of the world is based more upon habits of thinking than anything real. In his analysis of causality he found that we could only identify relations in space and time, no necessary connection between things could be discovered.

Hume believed all our ideas are ultimately founded on sensory experience, including our idea of cause and effect.

Hume needed to explain the basis of our belief in causation because it’s not obvious we get it through experience.

Hume claims that our idea of causation comes from frequently observing similar causes being followed by similar effects.

Furthermore he found that what we think of as causality amounts to no more than a constant conjunction from which we add a metaphysical concept of causality.

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Hume’s Stance on Scepticism

Hume distinguishes between two kinds of scepticism: antecedent and consequent scepticism, both of which come in an extreme and a moderate form. He identifies the extreme form of antecedent scepticism with the universal doubt of Descartes, which calls into question all former opinions and even the testimony of the senses. No claim is acceptable to the Cartesian sceptic unless is can be deduced from some indubitable first principle. Hume suggests

that, first, there is no first principle that is so self-evident as to be beyond doubt, and second, even if there were such a first principle, we couldn't advance beyond it, having not yet rescued from doubt our ability to reason deductively.

Though this extreme antecedent scepticism is unworkable, Hume commends it in a more moderate form. It consists simply in forming unprejudiced opinions, progressing by small steps from sound first principles, and examining one's conclusions frequently and carefully.

The scepticism of the Enquiry has been instead a kind of consequent scepticism that questions our habitual conclusions and judgments by doubting the grounds on which they are secured. Hume considers in particular the testimony of the senses, which suggests to us the existence of a world external to and independent of our senses. We are led by a powerful instinct to suppose that what our senses report to us is an accurate representation of this external world. However, not only do our perceptions change as we move about in the world, but there are cases of dreams or madness where our senses deceive us entirely. We can only justify our belief in an external world through experience, but experience cannot take us beyond the very perceptions that we are calling into doubt. Thus, Hume concludes, our belief in an external world is not rationally justified.

In its extreme form, consequent scepticism can lead us to complete inaction. While philosophers tend to draw a distinction between secondary qualities, such as colour, sound, or texture, and primary qualities, such as extension and solidity, our understanding of both is dependent upon experience: we cannot conceive of an extended body that has no colour or shape. If we doubt the testimony of our senses, we have no understanding of matter. Similarly, mathematical reasoning can lead us to counter-intuitive conclusions about space and time, presenting them to us as infinitely divisible. Consequent scepticism also leads us to doubt causal reasoning, since no conclusions that outstrip the observation of constant conjunction are rationally justified.

Such scepticism, however, dries up when we ask to what use we can put it. We cannot help but reason causally, and to refuse to do so on the basis of sceptical reasoning would lead us to desist from acting or judging altogether. Our natural instincts cannot help but reinstate what sceptical reasoning tries to dismantle.

While this extreme form of consequent scepticism is clearly unlivable, Hume again finds it useful in a more moderate form. Dogmatic and hasty reasoning may be mitigated by a constant recognition that reasoning can go astray and judgments should never be absolute. Reasoning about relations of ideas can only teach us mathematical truths, and cannot lead us to more general metaphysical principles. Reasoning about matters

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of fact is supported only by experience, and so we cannot provide logical proofs of the existence or non-existence of any entity. The closing line of the Enquiry urges us to ask of any book:

"Does it contain any abstract reasoning concerning quantity of number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames: For it can contain nothing but sophistry and illusion."

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Commentary on Section 12 of Enquiries Concerning Human Understanding:

This final section gives us a particularly clear understanding of Hume's relationship with naturalism and scepticism. While Hume concedes that certain irrefutable sceptical doubts can cast our reasoning into grave danger, our natural instincts should ultimately bail us out.

Before examining the consequent scepticism that has run throughout the Enquiry,we should briefly consider antecedent, or Cartesian, scepticism. Descartes opens the his book The Meditations by calling into doubt all the foundations of our judgments, in particular the testimony of the senses. The end of the First Meditation leaves us wondering if there is anything certain at all. In the Second Meditation, Descartes' Meditator assures us that we cannot doubt our own existence, and from this bedrock of certainty deduces the existence of God, of the external world, and all of Cartesian metaphysics.

Hume criticizes this approach, suggesting first that there is no secure first principle that is beyond doubt, and second that even if there were we could not proceed beyond it. Existence and non-existence, Hume asserts, can be confirmed only in experience, not through reason alone. Reason can establish mathematical truths, but nothing more substantial, and so the claim, "I exist," requires empirical evidence. Hume goes on to suggest that even if Descartes' Meditator could prove her own existence by means of pure reason, nothing else could be shown to follow from this claim. Her powers of deductive reasoning have been called into doubt, and so cannot be relied upon to deduce further truths.

Throughout the Enquiry, Hume has been employing a kind of consequent scepticism, as opposed to Descartes' antecedent scepticism. Descartes' scepticism is called "antecedent" because it demands some firm starting point before any reasoning can begin. Hume's doubts, on the other hand, arise in the course of his investigations into human understanding. Hume asks on what grounds we base our judgments and investigates their rational justification. Finding certain holes in our normal procedures--for instance, that our belief in necessary connection is not rationally justified--Hume is led to a kind of consequent doubt of our mental faculties.

Hume takes this doubt a step further in arguing that our belief in an external world is not rationally justified. All I know of the external world is what my senses report to me, but these reports can often be mistaken. Besides, they are only mental representations of external objects, and not the objects themselves, and I have no rational justification for inferring the existence of external objects based on mental representations. Thus, Hume concludes, we have insufficient evidence for the existence of an external world.

The extreme form of consequent scepticism concludes unhappily that none of our judgments are rationally justified. The only sensible thing to do in that case would be to suspend all judgment and to stop acting altogether. If I have no reason to think one thing rather than another or to do one thing rather than another, I am rendered completely immobile.

Hume's naturalism rescues him from this extreme scepticism. While neither our belief in an external world nor our belief in necessary connection are rationally justified, custom and habit lead us instinctually to accept them. Scepticism is useful in that it places limitations on our reason and makes us doubt what we might otherwise take for granted, but it is ultimately unlivable. I can doubt all I please in the comfort of my study, but in order to get by in the world I must at least assume that there is an external world and that my judgments and actions in that world make some sort of difference.

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Naturalism makes scepticism livable by reinstating certain kinds of thinking and reasoning as acceptable and trustworthy. Importantly, though, naturalism only reinstates relations of ideas and matters of fact, leaving metaphysics a little empty. Relations of ideas deal only with mathematical truths and matters of fact must be grounded in experience. Thus, a great deal of the subject matter of rationalist metaphysics--the existence of God, the immortality of the soul, the nature of matter, etc.--is discarded. We cannot answer such questions through reason alone, as a rationalist would want, and there is nothing in experience that can point us fruitfully toward any satisfying answers. Thus, the closing line of the Enquiry; that we commit to flames all books that engage in such empty, metaphysical speculations.

Summary:

Hume has presented us with a strongly-argued and challenging set of views. We began by establishing the basis of Hume’s empiricism.

1. The argument about ideas and impressions provided us with the rule that there are no ideas without impressions – which flatly contradicted the Rationalist argument that some knowledge was innate.

2. He then made a distinction between impressions and ideas based upon their impact upon us. Impressions he argued were immediate, vivid, lively in ways that ideas in the mind could not be.

3. In order to explain some elements of the working of the human mind, Hume explored the workings of the imagination. He argued that the imagination worked by:

compounding transposing augmenting diminishing.

This led to distinguishing between simple ideas – directly recorded from impressions, and complex ideas which were created out of simple ideas by the working of the imagination. So it is possible for us to imagine a gold mountain – or a unicorn – because the imagination works on ideas to compound and create these notions.

4. He went on to refine this argument yet further by suggesting that some ideas were based on impressions from outside of ourselves, but that others could arise from our internal sentiments – or feelings.

5. In the midst of this argument he mentioned the problem of the Missing Shade Blue – but dismissed it as a minor difficulty not worth worrying about!

6. He argued that if someone had never experienced a particular form of sensory experience – if someone had never seen colour for example – then they could not form any corresponding ideas that depended upon that experience. Further support to the argument that all ideas are based on impressions.

7. Hume’s fork. Hume suggested that knowledge split or divided (hence the idea of a fork’) into two forms, Matters of Fact and Relations of Ideas. He used the term a priori to mean Relations of Ideas, and a posteriori to mean Matters of Fact. Relations of Ideas provide certainty because they are either intuitively or demonstrably true. Matters of Fact however are contingency true.

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8. Hume then asked us to appreciate that our view of the world is based more upon habits of thinking than anything real. In his analysis of causality he found that we could only identify relations in space and time, no necessary connection between things could be discovered.

9. Furthermore he found that what we think of as causality amounts to no more than a constant conjunction from which we add a metaphysical concept of causality.

10. Lastly in the operation of the reason of animals Hume found that much they did was based on the same impulses of seeking pleasure and avoiding pain that motivated people. And that custom and habit were also powerful influences upon behaviour for both animals and people.

Hume is clearly an important philosopher who presents us even today with questions that are difficult to resolve. But that is not to say that there are no problems with his arguments.

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Evaluating Hume

Impressions and Ideas

There are perhaps other difficulties with his argument that might be less easy to deal with. In the first case are we really happy with his view of impressions and ideas? He seems to be dealing with both as though there were images – mental pictures that are clear for a time but then fade. He also argued that the main distinction between actual experiences and memories or ideas held in the memory was the vividness of experience by comparison to the weaker impact of either remembered experiences or imagined experiences. But is that really the case? Do people never have such powerful memories of events and places that they overcome immediate perceptions?

What about dreams or nightmares? People experience or feel things in dreams and nightmares that are not based directly on experience – they are imagined into existence out of the memory but whilst a person is experiencing a powerful dream or nightmare they can be intensely vivid. Much more so than the impression of being in bed!

Also, if we allow for ‘disease or madness’ as an exception, this means there must be something other than vivacity that distinguishes impressions from ideas. Also, arguably, some impressions seem more vivid than the corresponding idea.

The claim that all ideas can be traced back to sensory experience seems correct but is difficult to test.

Scientists often have to deal with ideas that don’t have any obvious impression such as ultraviolet.

Missing Shade of Blue

In the first case Hume himself provided an example that seemed to contradict his most basic argument. The Missing Shade Blue that we discussed earlier seemed to contradict his view that there could be no ideas without impressions. Although we determined that this might be explained by understanding colour as a complex idea – or at least by recognising that the categories of ideas – simple and complex – were not mutually exclusive. But this is not an argument that Hume developed – rather oddly he simply dismissed the example as a peculiarity. However, it could also be applied to other senses – such as the missing note on a

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Exam Prep

How effective are Hume’s arguments that all ideas derive from impressions? 6 Marks

How adequate is Hume’s theory of perception? 20 marks How far does Hume’s theory of impressions and ideas support his

empiricism? 13 Marks In section II of the enquiries, Hume provides a number of arguments to

support his empiricist accounts of perception, memory and imagination. Do you find his arguments convincing? 16 Marks

Knowledge and Doubt

musical scale. This leaves open the possibility of innate ideas which would undermine Hume’s entire argument.

Could we have got the shade of blue from a combination of other blues? If this were true, the missing shade of blue would be a complex idea built up from simple ideas. This doesn’t work - Hume is not talking about a shade of blue builtup from other ones. He is talking about a separate colour and colours are always simple ideas which relate to actual experiences. However, this is arguably naïve psychology as we perceive colours by comparison not as discrete concepts.

Could Hume just have said it wasn’t possible to form an idea of the missing shade of blue? Yes he could. He could have said that no person would be able to imagine what was in the gap and if the gap weren’t pointed out, he wouldn’t be aware that there was a gap.

This doesn’t work because Hume doesn’t do this.

This is not good enough – if you have this problem with the colour blue, it will apply to all colours. It will also apply to sounds and pretty soon we have a big list of counter examples that can’t be ignored.

It is also worth noting – That if Hume was so anxious to follow the scientific methods of people like Newton, you should not ignore examples that don’t fit in with your theories, you should look again at your theory.

Criticisms of Hume’s Causation

Hume asks where we get the idea of necessity from. According to empiricism, all ideas are grounded in sense experience but we do not have any sensory experience of necessity. Hume suggests a number of possible sources for this idea, all of which fail: We cannot deduce a priori that effects will follow their causes because causes don’t

resemble their effects. We couldn’t deduce a priori that a match would burst into flame if we had never seen matches before.

We do not derive this idea from a posteriori sources either: when we observe a cause and effect such as one billiard ball hitting another we only gain impressions of the first event followed by the second. We have no impression of the force or power linking the two.

We also can’t say that we get the idea of necessary connection by reflecting on the ability of our mind to move our body since the mechanism by which we can will our arm to move is just as hidden and mysterious as that which moves anything in the external world.

Hume’s answer to where our idea of necessity comes from is that it is a combination of instinct and observation. While we don’t observe necessary connections we do observe

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Exam Prep

How convincing is Hume’s argument concerning the missing shade of blue? 14 Marks

Knowledge and Doubt

“constant conjunctions”. This means that we see similar causes being followed by effects which are in turn similar to each other. Once we have seen enough examples of these constant conjunctions we have an instinctive tendency to link the two and regard them as necessary.

Thus our belief in causes in the natural world is not founded in reason but is simply a psychological habit we can’t help but fall into. For all we know, there might be no necessary connections in nature.

Hume’s answer to where our idea of necessity comes from is that it is a combination of instinct and observation. While we don’t observe necessary connections we do observe “constant conjunctions”. This means that we see similar causes being followed by effects which are in turn similar to each other. Once we have seen enough examples of these constant conjunctions we have an instinctive tendency to link the two and regard them as necessary.

Thus our belief in causes in the natural world is not founded in reason but is simply a psychological habit we can’t help but fall into. For all we know, there might be no necessary connections in nature.

Hume seems to depict causation as being no different from correlation. However, two events may be correlated without our assuming that they are causally connected, eg everyone who drinks milk dies (because everyone dies and everyone starts out in life drinking milk), but we do not assume that drinking milk kills us.

If Hume is right, he is claiming that all inductive reasoning is technically an irrational process. This means that all sciences, such as physics chemistry and biology, are founded on a process of judgement which bypasses reason.

Not only are these sciences deemed irrational but so too is the “science of man” that Hume himself is engaged in. How can Hume uncover psychological “laws of man” if, according to his own theory, there might be no necessary laws in nature at all?

If Hume’s account of causation is psychological in nature then it could be argued that it is an insufficiently sophisticated psychology. There are many examples of people who are exposed to constant conjunctions but who fail to make the instinctive judgement that these conjoined events are necessarily connected, eg the compulsive gambler who fails to connect her addiction to her misery despite them being constantly conjoined.

There are also examples of the opposite: where people infer the existence of necessary connections when they have only been exposed to a single instance, eg the refusal to eat lobster after a single occasion of food poisoning.

HOWEVER

There does seem to be a number of difficulties with Hume’s account of causation. However, many of these criticisms hang on an issue of interpretation. It is not completely clear whether Hume is saying that there are no

necessary connections in the world, or that those that existare necessarily unknown to us because of the limitations of our sense experience.

Hume seems to claim that there are some necessary connections of cause and effect, but that we can’t fully know them because of the limitations of inductive reasoning. This is a very plausible claim and so his view is completely justified.

An alternative position is that Hume’s view is not justified because he has taken the wrong approach from the start. Hume argues that all human knowledge is grounded in sensory experience. Possibly, causation is an innate idea but Hume’s empirical stance means he cannot accept the existence of innate ideas.

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Problem of Induction

Perhaps the central and most important argument raised by Hume is that we refer to as ‘the Problem of Induction’ – although Hume himself never used the term ‘induction’. Repeated attempts have been made since Hume first published his argument to try to refute his case. Many philosophers have found that attempts to prove Hume wrong provided an important

stimulus and starting point to their own deliberations. Some have argued that the whole case is simply misconstrued and that there is no ‘problem of induction’.

One strong case is that provided by the philosopher Karl Popper. Popper in effect begins with the view that there is no good reason to dispute the common-sense observation that the world is real and perceivable. That being the case we can put to one side any extreme or wild attempts to deal with Hume’s critique by calling into question the nature of existence. Having established that, Popper then takes the view that Hume is right – up to a point. There is, or at least would be a problem of induction if that really was the basis

for scientific knowledge or for that matter of our common understanding of how the world works.

In Popper’s view Hume in effect has a view of science that is based on a fairly basic understanding of its processes. After all science as a project was very much in its infancy in Hume’s time. We can see with our longer perspective that science is no about establishing firm truths on the basis of induction. Scientists do not in fact conduct series of experiments with the view of inducing from them general rules that tell us how things will behave in the future. Instead scientists are generally very well aware that each proposition that is put forward will only hold up until some way of disproving it is found. Or as Popper put it – scientists only construct conjectures about the nature of things.

So when we go to the car, put the key in the ignition and turn it, we are really waiting to see what will happen, rather than operating on the assumption that since the car started successfully when we did this before, it will always do so. In truth we know fine well that we are working with assumptions, with guesses that can prove to be wrong when we induce, when we move from events we have experienced in the past to events in the future. We can re-state Hume’s argument like this:

1. Any event will involve relations in space.2. Any event will involve relations in time.3. We can, by trial and error, try to discover if what occurred in the past leads to what will happen in the future.

Step 3 is not about induction; it is about trying this out with the understanding that we are not expecting or relying upon a necessary connection between events in the past and events in the future.

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Exam Prep

To what extent is Hume’s view of causation convincing? 20 Marks Does Hume succeed in showing that we do not use reason in gaining knowledge

of cause and effect? 16 Marks

Knowledge and Doubt

So we might argue that the logical argument that Hume presents; that there is no necessary connection between what happened in the past and what will happen in the future is correct – it’s just that as it happens that is not really how science works – nor is it altogether true of how we think. Instead we should understand scientific propositions as attempts at finding answers with the clear understanding behind them that they may well be and often are falsified and that is not a problem but actually part of the nature of the scientific process itself.

Habits of thinking

The psychological problem, that people’s habits of thinking lead us to induce from repeated past experiences what will happen in the future, can be dealt with in the same manner. Is it really unreasonable to make suppositions about the future on the basis of repeated examples when we know that what we are doing is making guesses – educated perhaps – but guesses nonetheless? In effect we are trying out things, we are testing to see if the repeated examples of events from the past does in fact hold true for our current experience. We put the key in the ignition and we try turning it to see if indeed the car does start.

Perhaps one of the dangers here is that we get lost in a maze of words that attempt to capture the real complexity of the world and our experience in a form that gives rise to its own set of complications.

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Exam Prep

What evidence is there in the Enquiries that Hume is an empiricist? Give examples to support your answer. 10 Marks

Knowledge and Doubt

Activities

True or False Test

The following test is based on Hume’s epistemology. State in the space provided whether the statement is true (T) or false (F).

The first two have been completed for you.

1 One of Hume’s aims is to discover how the human mind works. T

2 On Hume’s account, a ‘perception’ is a process in the mind. F

3 Impressions have less forcefulness and vivacity than ideas.

4 If I am feeling happy, then there is an impression in my mind.

5 The imagination can combine any two simple ideas.

6 Memory is merely passive, while the imagination is active, on Hume’s account.

7 Hume believes that some ideas are innate.

8 Hume believes that we would not be able to have an idea of the missing shade of blue.

9 Hume uses the term ‘Relations of Ideas’ to refer to a priori beliefs.

10 Matters of fact are a posteriori and contingent.

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Reading Questions

Read the chapter of Philosophy: The Classics by Nigel Warburton that your teacher gives you and answer the following questions as you go along. Use a separate sheet for answers.

1. What is scepticism?

2. How did Hume regard reason?

3. Which of Hume’s books is the Enquiry essentially a rewrite of?

4. What is Hume’s aim in the Enquiry?

5. What are ‘perceptions’ according to Hume?

6. What does Hume mean by the term ‘impressions’?

7. Where do our ‘ideas’ come from?

8. How can we tell the difference between impressions and ideas?

9. According to Hume, how is it possible to imagine a golden mountain even though we’ve never seen one?

10. What arguments does Hume provide for his belief that all knowledge comes from experience? Provide 2.

11. What is the ‘missing shade of blue’ meant to be an example of?

12. What two sorts of knowledge does ‘Hume’s Fork’ distinguish?

13. What does Hume think we should do with philosophy books which fall into neither category of knowledge?

14. Whose philosophy is Hume theory of impressions and ideas based on?

15. How does the ‘missing shade of blue’ undermine Hume’s position?

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Suggested Reading

Arrington, R.L. (1999) A Companion to the Philosophers. Blackwell.

Jenkins, J. J. (1992) Understanding Hume. Edinburgh University Press.

Nadler, S. (ed.) (2002) A Companion to Early Modern Philosophy. Blackwell.

Priest, S. (1990) The British Empiricists. Penguin.

Hume, D. (1999) An Enquiry Concerning Human Understanding. (ed. Beauchamp, T. L.) Oxford University Press.

Warburton, N. (1998) Philosophy – The Classics. Routledge.

Kenny, A. (1998) A Brief History of Western Philosophy. Blackwell.

O’Connor, D.J. (1964) A Critical History of Western Philosophy. Macmillan.

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