descartes mediations lecture

7/28/2019 Descartes Mediations Lecture

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Lecture #5

Descartes Meditations on First Philosophy

Meditation 1

Descartes begins the First Meditation by giving us a metaphor for how

beliefs work. He says that our beliefs are like a building.

Some beliefs are foundational and provide support for the rest of our

beliefs. The non-foundational beliefs are simply inferred from the

foundational beliefs.

This view of knowledge is known as foundationalism.

If many errors are discovered within our building of beliefs, it is likely

that something is wrong with the foundation. Descartes found himself in

this situation.

The only way a foundation can be repaired is to destroy the entire

building and start over.

Descartes project was to tear down the entire building of his beliefs,

because of its bad foundation, lay a new foundation, and start building

over again.

In order to destroy the building of his beliefs, he only needs to destroy

the foundation. All of the beliefs built on this foundation will then come

crashing down with it.

So what was the foundation of all of his beliefs?

Empiricismthe view that we acquire truth through the senses.

His goal at this point is therefore to show that this empiricism is a bad

foundation for knowledge.


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The Method

Descartes will use doubt as the tool both (1) to tear down the building,

and (2) to discover a foundation that is absolutely firm and stable.

When a product such as steel is tested, it is subjected to pressures greater

than it will face in its normal use.

In the same way, Descartes subjects his foundational beliefs to the

severest test possible.

We call this test methodological (radical, hyperbolic) doubt.

If Descartes can come up with any reason whatsoever, no matter howridiculous it may sound, to doubt a foundational belief, then it will be

rejected as less than certain.

In order to test his original foundation, he conceives of three forms of

methodological doubt:

(1) Sensory Deception (Mirage Doubt - my senses sometimes deceive

me): this allows him to doubt some of his sense perceptions.

(2) Dream Doubt (Matrix Doubt - I cannot tell the difference between

dream life and waking life): this allows him to doubt all of his sense

perceptions.

(3) Defective Nature Doubt (Deceiving God, Evil GeniusI may be

constructed in such a way that I have hallucinations and make mistakes

when doing math): allows him to doubt all of his sense perceptions and

mathematics.

Defective Nature Doubt is more complicated because Descartes seems to

give us three different versions.

He talks first about a deceiving God, then about something like


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evolution, and then about a malicious demon.

Here Descartes seems to be trying to cover all of his bases.

If the reader believes in God and is willing to consider without offensethe possibility of God being a deceiver, then the deceiving God version

will work.

If the reader is an atheist and believes we came into being through some

kind of evolutionary process, then the argument is even easier to make,

since if we can to be through accidental processes then we are even more

likely to be deceived when doing thing like math.

If the reader believes in God and is offended by the very thought of Godbeing a deceiver, then we can use the malicious demon argument.

Perhaps we are being deceived by a demon.

The methodological doubt has shown that empiricism is a bad

foundation. Now its task is to reveal a good candidate for the new

foundation, if there is one.

By the end of Meditation One, Descartes has eliminated his originalfoundation (empiricism), and also found that mathematics is not a good

candidate for the new foundation.

Descartes found himself disoriented by this discovery since he no longer

had a basis for knowledge on which to rely.

Lecture #6


Meditation 2

In spite of the disorientation produced by the results of Meditation One,

Descartes is determined to continue with his project of searching for a


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new foundation that is not susceptible to any form of doubt.

If he finds that there is nothing certain, then he will become a skeptic

(someone who believes that knowledge is impossible).

Even if his senses deceive him, he is dreaming, or God, evolution, or an

evil genius is causing him to hallucinate and make mistakes when doing

math, the fact remains that he is thinking when he is deceived.

Doubt itself is a form of thinking.

So, regardless of whether he is deceived or not, Descartes can at least

say that when he is thinking, he exists.

This will be the new foundation for knowledge: I think, therefore I

am.

This cannot be doubted no matter how one tries. This belief is not

susceptible to any of the three forms of methodological doubt.

Sensory Deceptioneven when my senses are deceiving me, being

deceived is a form of thinking, so I exist as a thinking thing.

Dream Doubteven if I am dreaming, dreaming is a form of thinking,

so I exist as a thinking thing.

Defective Nature DoubtEven if God, evolution, or an evil genius is

causing me to hallucinate or make mistakes when doing math, these are

still forms of thinking, so I exist as a thinking thing.

Thus Descartes methodological doubt has worked! It has successfullyeliminated his old unreliable foundation (empiricism) and discovered a

new foundation that is absolutely certain.

The new foundation = I exist as a thinking thing.


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But we have to be careful here not to build too much into this idea of the

I that exists.

Descartes therefore goes back through his previous doubts in order to

eliminate everything from this I that was shown to be uncertain.

The I cannot include the body since I am aware of my body through

the senses. Since I doubted whether the senses are giving me truth, I

cannot be sure that I actually have a body.

The Wax Example:

At this point in the Second Meditation, Descartes recognizes the surprise

in his reader that the mind is supposed to be more clearly understoodthan the body.

It does seem that we know the things with which we come into contact

through our five senses very clearly. It seems clearer and more obvious

that I have a body than that I am a mind.

Descartes turns at this point to his famous wax example.

This example is designed as an argument against empiricism and for

rationalism. Specifically it is designed to show that thought is a more

reliable way of getting at the truth than sense perception.

Descartes observes a piece of wax in front of him. Many have thought

that Descartes was talking about a candle, but he seems to be talking

about just a plain piece of wax made from honeycomb.

The five senses give Descartes information about the piece of wax:

It has a certain color, shape, size, smell, hardness, temperature, and

sound when it is tapped.

But when Descartes brings it closer to the fire, all of these characteristics


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change. By the time the changes are complete, the piece of wax has a

different color, shape, size, smell, hardness, temperature, and sound

when it is tapped.

Yet we still say that it is the same piece of wax.

What is telling us that it is the same piece of wax?

All we can say now about the wax is that it is something extended,

flexible, and changeable.

Can our senses tell us that? Well, first we have to talk about the

imagination. The imagination for Descartes is the ability of the mind to

form specific, determinate pictures of the kinds of things we experiencewith our senses.

Can the imagination form a specific, determinate picture of something

that is only extended, flexible, and changeable?

No. It can only picture things that have definite characteristics.

But the mind can still think about indefinite extended, flexible,changeable things without forming a picture.

So if the real nature of the piece of wax is that it is an extended thing

that is capable of taking on many different characteristics, then the

senses and imagination are incapable of giving us the real nature of the

piece of wax.

The mind, on the other hand, apart from the senses and the imagination,

is able to tell us the real nature of the piece of wax.

Therefore, the mind is better known than the body.

It is not the act of sense perception that tells us it is the same piece of

wax, but thinking about it.


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In addition to being an argument against empiricism, this wax example

also sets us up for the main argument of the whole book: The real

essence of physical things is extension, and extension is best understood

through mathematics.

But Descartes cannot make this argument yet.

Lecture #7


Meditation Three

At this point, all Descartes is certain of is that he exists as a thinking

thing.

But since he is certain of this, he does seem to know what it is like to be

certain about something.

The main characteristic of his certainty concerning the Cogito (I think,

therefore I amthe first item of knowledge) is that he has a clear and

distinct perception of it.

What you experienced when you thought about the Cogito was a

immediate and instantaneous recognition that it cannot be false.

This is what it means for something to be certain.

As a result, Descartes lays down at the beginning of Meditation Three a

general rule: whatever I clearly and distinctly perceive is true.

In the past Descartes thought he was clearly and distinctly perceivingthings that turned out to be false. What do we say about this?

First, he was not being as careful then as he is now. So, many times

when he thought he was perceiving clearly and distinctly, he was not.

This is why meditation is required.


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Second, we need to talk about the minds faculty of judgment to further

understand this problem.

At this point though, Descartes is still stuck with knowing only that he

exists as a thinking thing.

This means that the only resources he has for continuing his pursuit of

knowledge are the thoughts he has. He still does not know whether

anything exists outside of him.

So Descartes begins an inventory of the various thoughts that appear in

his mind, hoping to find some thought that uniquely points to the

existence of something outside of him.

He cannot doubt that the ideas and thoughts he is having are appearing

before his mind.

But he used to think that there were things outside of him that were the

sources of these ideas and thoughts.

When I see the table in front of me, I cannot doubt that there seems to be

a table there. But I can doubt whether there really is a table outside ofme causing to have that sense perception (that seeming).

The problem here is one of judgment, which Descartes will address in

Meditation Four.

He also has ideas concerning mathematics, that 2+3=5 and a triangle has

three sides.

But he doubted whether this was true, even though it seemed to be clearand distinct, because he thought that God could be deceiving him when

he performs even the simplest mathematical equations.

So, before he can go on, he needs to address the problem of the

existence of God.


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First Argument for the Existence of God:

Descartes recognized that each of his thoughts or ideas appears to be

from one of three sources: it is innate (present in his mind from the

beginning), adventitious (coming from something outside of him), orinvented by him.

My sense perceptions seem to be coming from something outside of me

because they often appear to my mind against my will.

But this does not necessarily mean that they are coming from outside of

me (impulses).

The unique thought he finds is the idea of God.

The idea of God that Descartes finds in his mind has one of three

sources: it is innate, adventitious (coming from outside of him), or

invented by him.

We should also distinguish here between innate ideas that originally

came from something outside of us, and innate ideas that just arose

originally from our nature.

At least it seems that Descartes would have to make this distinction.

At this point Descartes discusses the difference between objective

reality and formal reality.

The definitions he is using are definitions that were used in the Middle

Ages, so dont think of them as having the same meaning throughout the

history of philosophy.

Objective Reality = representational reality; the amount of reality that an

idea representing some object has.

Formal Reality = the amount of reality that the object causing the idea


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has.

Descartes gives us another rule: There must be at least as much reality in

the cause as there is in the effect.

Stated more precisely, there must be at least as much formal reality in

the cause of an idea as there is objective reality in the idea.

The ideas I have of physical objects are ideas of finite substances.

Substance = that which can exist by itself, as opposed to accidents which

can only exist in something else.

So the cause of these ideas I am having of a physical object must have atleast as much formal reality as the idea has objective reality.

The idea represents a finite substance, so it has as much objective reality

as a finite substance would have formally.

Thus, the cause of this idea would have to have as much formal reality

as a finite substance has.

In other words, the idea of a finite substance would have to be at least a

finite substance.

I, as a thinking thing, am a finite substance. So, I could have been the

cause of all of my ideas of finite substances, including my sense

perceptions.

The idea of God, on the other hand, is an idea of an infinite substance.

The idea has as much objective reality as an infinite substance wouldhave formally.

Therefore, the idea of God would have to be caused by something that

has an infinite amount of formal reality.


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I do not have an infinite amount of reality, since I am a finite substance.

So, my idea of God had to have been caused by some infinite substance

outside of me.

Therefore, God exists outside of me and causes me to have the idea of

God.

This infinite being would possess all of the perfections that I do not fully

grasp but "somehow reach in my thought. (52)

As such, God could not be a deceiver since all fraud and deception

depend on some defect. (52)

A Series of Questions and Answers to Help You Understand

Descartes Third Meditation Argument for the Existence of God

In order to better understand this short dialogue, you need to know the

following:

1. Substances are things that can exist by themselves, as opposed to

accidents which can only exist in something else. A tree, a car, aperson, a computer monitor are all examples of substances. A particular

color, a particular texture, a particular size are all examples of accidents.

2. There are three kinds of things that we can think of existing:

a. Infinite Substancesthese are substances that have no lack or

deficiencies; they are unlimited.

b. Finite Substancesthese are substances that do have lack anddeficiencies; they are limited.

c. Accidentsthese can only exist in a substance; for example, we never

experience a color unless it is attached to some substance.


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Now for the questions and answers.

Question: What kind of being am I (at this point in Descartes

Meditations)?

Answer: A thinking thing (a substance).

Question: As a thinking thing, how much formal (actual) reality do I

have?

Answer: A finite amount.

Question: How do I know this?

Answer: Because I have doubts and not all of my ideas are clear and

distinct.

Question: What kind of being does the idea of God present to me?

Answer: An infinite substance.

Question: If the cause of an idea must have at least as much formal

(actual) reality as the idea has objective (representational) reality, then

how much formal (actual) reality would the cause of an idea of a finite

substance have to have?

Answer: It would have to be at least a finite substance. For example,

since I am a finite substance (in reality) I could have invented an idea of

another finite substance, such as the idea of a dog.

Question: How about the cause of an idea of an infinite substance?

Answer: It would have to be at least an infinite substance.

So, I could not have been the cause of my idea of God and there must be

something outside of me that is an infinite substance and caused me to


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have that idea.

Therefore, God exists.

At least that is how Descartes is attempting to argue for the existence ofGod. Whether or not his argument is any good is another question

Lecture #9


Meditation Four

Descartesbuilding of knowledge now comes together fairly easily. He

has removed the biggest obstacles and now begins to see how to put the

whole thing together.

I think I see a way forward to the knowledge of other things. (53)

Before Meditation Three Descartes knew only that he is a thinking thing.

By the end of Meditation Three he knows that God exists and is not adeceiver.

For in every case of trickery or deception some imperfection is to be

found; and although the ability to deceive appears to be an indication of

cleverness or power, the will to deceive is undoubtedly evidence of

malice or weakness, and so cannot apply to God. (53)

Since he only doubted the certainty of mathematics because of the

possibility of a deceiving God, he can now establish that mathematics isabsolutely certain when clearly and distinctly perceived.

This then is the third item of knowledge in his building.

God exists and is not a deceiver, so all of my faculties were given to me


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by Him. Thus, my faculties are not such that they will deceive me.

But then how do I count for all of the errors that I make?

Whatever God creates would have to be perfect of its kind. But sayingthat something is perfect of its kind is not to say that it is absolutely

perfect.

For example, a perfect car would not possess every possible property,

but rather only those properties that are appropriate to a car. A car is not

designed to fly, so a perfect car would not fly.

If a perfect being created me, then I am perfect of my kind, but not

perfect in every way.

The cause of my errors is found in the combination of my intellect and

my will.

The intellect is the part of me that enable[s] me to perceive the ideas

which are subjects for possible judgments. (56)

The will simply consists in our ability to do or not do something (thatis, to affirm or deny, to pursue or avoid); or rather, it consists simply in

the fact that when the intellect puts something forward, we are moved to

affirm or deny or to pursue or avoid it in such a way that we do not feel

ourselves tobe determined by any external force. (57)

When the intellect presents a clear and distinct idea to my will, my will

cannot help but affirm it. The force of clear and distinct perceptions is so

great that it moves my will to automatically affirm.

But when my intellect presents an idea to my will that is less than clear

and distinct, my will is in a state of indifference regarding the idea.

It does not know whether it should affirm the idea or deny it.


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This is caused by the fact that the scope of the will is wider than that of

the intellect. (58)

The scope of the will is infinite. The will can affirm or deny anything

presented to it by the intellect.

The intellect, on the other hand, is not infinite in scope. It cannot present

ideas of everything, and it cannot always present clear and distinct ideas.

We make errors in judgment when we affirm or deny ideas that are not

yet clear and distinct.

Descartes recommendation: If, however, I simply refrain from making

a judgment in cases where I do not perceive the truth with sufficientclarity and distinctness, then it is clear that I am behaving correctly and

avoiding error. But if in such cases I either affirm or deny, than I am not

using my free will correctly. (60)

In those cases where my intellect presents clear and distinct ideas, my

will cannot help but affirm them.

But in those cases where my intellect presents ideas that are not clearand distinct, I should refrain from making any judgment until the ideas

are clear and distinct.

This is very similar to the wisdom of Socrates (admission of ignorance).

Lecture #10


Meditation Five

Now that Descartes has established what he has concerning the correct

foundation for his building of knowledge, the existence of God who is

not a deceiver, the reliability of mathematics, and the truth of clear and


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distinct perceptions, he is able to pursue the completion of his building

by making sure the rest of his ideas are clear and distinct.

Before considering whether or not material bodies actually exist, he first

considers what a clear and distinct idea of material bodies would looklike.

He discovers that when he is thinking clearly and distinctly concerning

material bodies, he thinks of them in terms of their quantifiable

characteristics such as their length, breadth, depth, size, shape, position,

and motion.

These are all properties of the extension of ideas of material bodies.

Thus he establishes that the essence of material bodies, whether they

exist or not, would have to be their extension.

Extension is simply the concept of a thing as taking up space and thus

having geometrical characteristics.

If the essence of material bodies is extension, and all of the

characteristics of an extended thing can be understood throughmathematics, and our mathematics is reliable, then the best way to

understand ideas of material bodies would have to be through

mathematics.

So, clear and distinct perception of material bodies occurs when they are

considered mathematically.

Thinking of material bodies this way would have enabled Descartes

predecessors to eliminate the idea that the earth is in the center of theuniverse.

After establishing this very important piece of his building of knowledge

(really the punchline of the whole book), Descartes turns to a second

argument for the existence of God.


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Descartes Fifth Meditation argument for the existence of God begins

where his argument that mathematics is the best way to understand

material objects begins, by considering what is essential to the idea.

If we think about the idea of a triangle, we will find that part of theessence of the idea is that it is a three sided figure.

Another part of the essence of the idea of a triangle is that its three

angles equal two right angles.

If we were to remove these features of the idea of a triangle, we would

no longer have the idea of a triangle.

In other words, these properties are essential to the idea.

When we think about the idea of a supremely perfect being, so the

argument goes, we will find that existence is part of the essence of this

idea.

In other words, we can no more remove existence from the idea of God

than we can that it is a three sided figure from the idea of a triangle.

If we remove existence from the idea of a supremely perfect being, we

would no longer have the idea of a supremely perfect being.

Thus existence is part of the essence of the idea of a supremely perfect

being.

On this basis, Descartes argues that we can infer that this supremely

perfect being does actually exist.

Many people are not satisfied with this argument; some people are.

What many people have a problem with is Descartes move from talking

about the features of his ideas to talking about the real existence of God.


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The criticism here is probably that even if we were to admit that

existence is essential to the idea of a supremely perfect being, all this

would give us is the fact that if we remove existence from the idea, we

no longer have the idea of God.

But this does not mean that God then must really exist. We cannot jump

from facts about our idea to facts about existence.

This is a legitimate criticism and should be considered.

Another famous criticism comes from the philosopher Immanuel Kant.

Kant claims that existence is not a predicate.

Predicates are properties of things that we express through language.

For example, if I say My car is silver, My car is the subject and being

silver is the predicate.

With this sentence I am predicating something where my care is

concerned.

There is a fact of the matter where the color of my car is concerned.

When Descartes speaks about triangles being three sided figures, this is

also saying that being a three sided figure is a predicate of any triangle.

Kants complaint is that existence is not a proper predicate.

When I say Mycar is silver, the word is is what we call a copula.

It is sort of the bridge between the subject and the predicate.

To make a claim about somethings existence is to say, for example,

My car is.

Kant claims that this is not predication. You have not given a proper


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predicate, only a copula.

So when Descartes frames his argument the way he does, what he says

about predicates is true, but when talking about God he has not given us

any predicate to consider.

Either way, Descartes believes that he has proved in the Fifth Meditation

both that the essence of material objects is extension and that God exists

(a second time).

Meditation Six

We can see from the title of the Sixth Meditation that Descartes will be

focusing on proving that material objects exist and a discussion of the

difference between mind and body.

His discussion of the difference between mind and body will give us the

central problem of modern philosophy after Descarteswhat we usually

refer to as the mind/body problem.

But first Descartes considers the kinds of proof he can find that the

material objects that appear in his experience actually exist apart from

his thinking.

He explains the difference, as he sees it, between the imagination and

the understanding.

The imagination is the part of the mind that thinks in images or pictures.

For example, if I picture a pizza in my mind, I am imagining it; that

picture appears in my imagination.

If I think, instead, in terms of concepts that do not include pictures, then

these thoughts appear in the understanding.


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Descartes claims that the ability to picture things in the imagination is

not essential to who he is (a thinking thing), and on this basis the cause

of his ability to picture things (which are always extended) is probability

something external to him.

But this only gives him a probable conjecture. (51)

He is interested in a stronger argument for the existence of material

objects.

So he considers what exactly takes place when he has the experience of

sense perception.

He notices two things about his sense perceptions:

(1) They come to him without his consent. In other words, he cannot

have a sense perception of an object at will, and he cannot choose to not

have a sense perception he is having. (52)

(2) They are much more lively and vivid than the other pictures he

sees in his imagination through memory or when he decides to picture

some object. (52)

These two features of his sense perceptions suggest to Descartes that the

cause of his sense perceptions are actually real objects existing outside

of him impressing themselves on his senses.

The faculty of sense perception seems to be a passive faculty that simply

receives impression from external objects. This is especially suggested

by the fact that they come to us against our will. (55)

The objects that appear to my faculty of sense perception seem to be

external and seem to be real. The fact that God is not a deceiver seems to

prove that material objects do in fact exist external to the mind.

Descartes also notices something special about one of the objects he


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encounters in his sense perceptions: his own body.

What is special about it is that he is aware of things taking place inside it

(pleasures, pains, appetites, emotions, etc.), but he is not aware of

similar things taking place in other material bodies.

This suggests to him that his body and mind are uniquely joined together

to form a single unit.

The question here becomes: how distinct are the mind and body? What

is the essence of mind, and what is the essence of body?

He has actually already considered both of these questions:

The essence of mind is thinking, and mind is non-extended.

The essence of body is extension, and body is non-thinking. (54)

The mind/body problem focuses on whether this distinction is really the

case, and if it is, how the two interact with one another.

The question now becomes, at the end of Decartes book, how do the

senses fit into this overall picture?

They used to be the very foundation of Descartes building of

knowledge.

What do we do with them now?

The senses now have a different purpose than Descartes previously

thought.

The senses are not designed to give us access to the truth.

Instead, they are designed to give us the kind of information that will

allow us to preserve the union between the mind and the body.


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So we can put at the top of Descartes building of knowledge that the

purpose of the senses is to inform the mind of what is beneficial or

harmful to the composite of which it is a part. (57)

This is a clear and distinct idea of the senses and when we think of themin these terms, according to Descartes, we will not be mislead by them.

The last loose end Descartes discusses is his dream doubt from the First

Meditation. What is he going to do with this?

He tells us in the last paragraph of the book that when we think more

clearly about dreaming and waking life, we find that waking life is

linked together by memory, while dreams are not.

In other words, waking life, after being interrupted by periods of sleep,

always picks up where it left off. We have memory of where it left off,

and it always picks up from there when sleep ends.

Dream life is not linked together this way. Thus we can distinguish

between the two.

Conclusions

As mentioned before, Descartes Meditations gives us the central

problem of modern philosophy (the mind/body problem).

It also gives another starting point for doing philosophy that we can add

to Socrates admission of ignorance.

Descartes Meditations gives us a strong argument for starting any

philosophical inquiry with consciousness.

In other words, once I admit ignorance, I need to start building

knowledge. How am I going to start?


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According to Descartes, and modern philosophy after him, I must start

with my awareness of being conscious. I find myself existing as a being

that is conscious of certain things. This I know for sure.

From there I begin to ask questions about the nature of my awareness,and the nature of the things of which I am aware.

Before loading my existence up with all sorts of presuppositions about

myself and the world, I should be careful to only add items to my belief

structure that follow from my awareness of my existence as a

consciousness.

Another extremely influential part of Descartes Meditations is his

discussion of clear and distinct ideas.

Modern philosophy after Descartes continues to use this language and

attempts to work toward having clear and distinct ideas about whatever

topic is at hand.

Next we will look at how the mind/body problem has evolved in

philosophy.


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Summary of Descartes'Meditations on First

Philosophy

Meditation I

1. A firm foundation for the sciences requires a truth that is absolutely

certain; for this purpose, I will reject all my beliefs for which there is

even a possibility of doubt, and whatever truths are left will be

absolutely certain.

2. To this end it is not necessary to go through all my beliefs

individually, since they are all based on a more fundamental belief. If

there is any reason to doubt this foundation belief, then all the beliefs

based on it are equally doubtful.

3. All my beliefs about the world are based on the fundamental belief

that the senses tell me the truth. But this belief is not absolutely certain.

It is at least possible that everything my senses tell me is an illusioncreated by a powerful being. Therefore, there is some reason to doubt

my foundation belief, and thus all my beliefs about the world are

doubtful; none of them can serve as the foundation for science.

Meditation II

1. If all my beliefs about the world are doubtful, is there any truth which

can be absolutely certain? Yes. Even if all of my experience is anillusion, it cannot be doubted that the experience is taking place. And

this means that I, the experiencer, must exist.

2. Since the only evidence I have that I exist is that I am thinking

(experiencing), then it is also absolutely certain that I am a thing that


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thinks (experiences), that is, a mind.

3. Since I am not certain (yet) that the physical world (including my

body) exists, but I am certain that I exist, it follows that I am not my

body. Therefore, I know with certainty that I am only a mind.

4. I am much more certain of my mind's existence than my body's. It

might seem that in fact we know physical things through the senses with

greater certainty than we know something intangible like the mind. But

the wax experiment demonstrates that the senses themselves know

nothing, and that only the intellect truly knows physical things. It

follows that the mind itself is known with greater certainty than anything

that we know through the senses.

Meditation III

1. Every idea must be caused, and the cause must be as real as the idea.

If I have any idea of which I cannot be the cause, then something besides

me must exist.

2. All ideas of material reality could have their origin within me. But the

idea of God, an infinite and perfect being, could not have originated

from within me, since I am finite and imperfect.

3. I have an idea of God, and it can only have been caused by God.

Therefore God exists.

Meditation IV

1. Only an imperfect (less than perfectly good) being could practice

deliberate deception. Therefore, God is no deceiver.

2. Since my faculty of judgment comes from God, I can make no


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mistake as long as I use it properly. But it is not an infinite faculty; I

make mistakes when I judge things that I don't really know.

3. God also gave me free will, which is infinite and therefore extends

beyond my finite intellect. This is why it is possible to deceive myself: Iam free to jump to conclusions or to proclaim as knowledge things that I

don't know with absolute certainty.

4. I therefore know now that if I know something with absolute certainty

(clearly and distinctly), then I cannot be mistaken, because God is no

deceiver. The correct way to proceed is to avoid mistakes and limit my

claims to knowledge to those things I know clearly and distinctly.

Meditation V

1. Now I want to find what can be known for certain about material

objects. Before deciding whether they exist outside me, I know that my

ideas of them consist of shape, size, motion, etc. I also know that by

thinking about these attributes I can discover certain facts that are

necessarily true about them (the truths of geometry, for example).

2. I do not invent ideas such as geometrical shapes, nor do I get them

from sensory experience. Proof of this is the fact that I can discover

geometrical truths about figures which I cannot imagine.

3. Just as, by thinking about my ideas of geometrical shapes, I can

discover truths that necessarily belong to them, I can do the same with

God. I have a clear and distinct idea of a perfect being. Perfect = lacking

nothing. I cannot conceive of a being that is perfect but lacks existence.Therefore, existence necessarily belongs to God.

4. This doesn't mean that my thinking of something makes it exist. If I

conceive of a triangle, I must conceive of a figure whose angles equal

two right angles. But it doesn't follow that the triangle must exist. But


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God is different. God, being perfect, is the one being to whom existence

must belong. Thus, when I conceive of God, I must conceive of a being

that exists.

5. Because God, being perfect, is not a deceiver, I know that once I haveperceived something clearly and distinctly to be true, it will remain true,

even if later I forget the reasoning that led me to that conclusion. I could

not have this certainty about anything if I did not know God.

Meditation VI

1. All that is left is to determine whether material objects exist withcertainty. I know that the abstract shapes representing them are real,

since I perceive them clearly and distinctly in geometry.

2. Furthermore, I have a faculty of imagination, by which I can conceive

of material objects, and which is different from my intellect. That it is

different is proven by my ability to do geometry with unimaginable

figures. Only intellect is necessary for my existence.

3. The most likely explanation for the existence of my faculty of

imagination is that my mind is joined with a body that has sense organs.

This is even more likely in the case of the faculty of sensation.

4. It formerly seemed that all my knowledge of objects came through the

senses, that their ideas originated from and corresponded to objects

outside me. It also seemed that my body belonged especially to me,

although I did not understand the apparent connection between mind and

body.

5. Then I found it possible to doubt everything. Now I am in the process

of systematically removing doubts where certainty exists.

6. Now that I know God can create anything just as I apprehend it, the


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distinctness of two things in my mind is sufficient to conclude that they

really are distinct. Thus I know I exist, I am a thinking thing, and

although I may possess a body, "it is certain that this I is entirely and

absolutely distinct from my body, and can exist without it."

7. My faculty of sensing is passive and thus presupposes a faculty of

causing sensation, which cannot be within me, since some ideas come to

me without my cooperation and even against my will; it therefore

belongs to something else. This is either a body or God. But since God is

not a deceiver, he doesn't plant these ideas directly in me (doesn't make

me believe in a nonexistent world). Therefore corporeal things exist. My

senses might mislead me about the details, but I know at least that the

ideas that I clearly and distinctly understand--geometrical properties--belong to these bodies.

8. Nature is God's order; thus it has truth to teach me. For example, that I

am present to my body in a more intimate way than a pilot in a ship. And

that there are other bodies around me that affect me in various ways, that

should be pursued or avoided; the senses thus act to preserve and

maintain the body.

9. But I also make some judgments on my own that are not justified by

nature's teachings, particularly in assuming objects and their qualities to

be exactly as my senses report them, that sense qualities reside in them,

etc. It is the fault of my judgment that I use sense perception as a direct

apprehension of the essences of external bodies; there is nothing

inherently deceptive about sensation.

10. Another problem is the misleading signals I sometimes get from my

own body, which induce me to commit errors. A body with edema, forexample, will have an inclination to drink, when in fact this is something

it ought to avoid. How can God permit this?

11. The body is divisible, the mind is not. Further, the mind gets

impressions from the parts of the body not immediately, but via the


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brain. Therefore the nerves running from the parts to the brain might be

stimulated (pulled) somewhere in between, registering motion in the

brain just as if the body part were affected. When everything functions

normally, the sensations in the mind are the best and most appropriate

for the purpose of maintaining health. So the exceptions prove thegoodness of God in making us this way.

12. By using more than one sense, and memory, I can avoid errors of the

senses of this kind. So I should get rid of the excessive doubts I started

with, especially those premised on dreaming, since I can easily

distinguish dreaming from waking by the continuity of the latter. I can

trust the truth of my ideas as long as my senses, memory, and

understanding are all consistent with one another.

Copyright 1999 James T. Anderson

descartes mediations lecture

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