Perception as a Way of KnowingHwa Chong Institution

EL Strand One 2012Prepared by Mrs Jenny Wong

Perception as a Way of Knowing

“Did you ever wonder if the person in the puddle is real, and you're

just a reflection of him?"

~Calvin and Hobbes

"How do we know that the sky is not green and we are all colour-blind?" ~Author Unknown

Perception as a Way of Knowing

Empiricism is a theory of knowledge that asserts ALL knowledge is ultimately based on

perceptual experience.Aristotle  But if life itself is good and pleasant (...) and if one who sees is

conscious that he sees, one who hears that he hears, one who walks that he walks and similarly for all the other human activities there is a faculty that is conscious of their exercise, so that whenever we perceive, we are conscious that we perceive, and whenever we think, we are conscious that we think, and to be conscious that we are perceiving or thinking is to be conscious that we exist...

Perception as a Way of Knowing

Perception as a Way of Knowing

Philosophers associated with empiricism

John Locke David Hume

George Berkeley(UC Berkeley named after him)

Leonardo Da Vinci once said,"All our knowledge has its origins in

our perceptions.”

Empiricism is a theory of knowledge that asserts

ALL knowledge is ultimately based on

perceptual experience.

By the end of this lecture, students will

be able to understand why perception is an active not a passive process, and the implications this has for our view of the world;

be aware of the often unnoticed role that reason plays in interpreting our sensory information;

be able to discuss the basic philosophical problems with empirical knowledge;

be able to discuss the meaning of the phrase `The mental construction of reality’ ;

be able to notice in everyday life those times when the senses are not reliable;

be able to understand some of the knowledge issues which perception brings up, the limitations of the senses as well as exploring the basic philosophical problems with empirical knowledge.

Aims and Objectives

We `naturally ’ trust our senses as we generally accept our senses as the bedrock of certainty and reliability.

“ I’ll believe it when I see it.”

“Seeing is believing.”

We even have a word for something ridiculous which we call `non-sense’.

Sense perception is generally described as a physical response of our senses to stimuli.

Perception as a Way of Knowing

We perceive the world through our 5 senses (basically).

Perception as a Way of Knowing

The Science of the Senses:http://www.youtube.com/watch?v=o_tar1s4ZJY

 

Bats and dolphins use sonar for navigation.

Homing pigeons and sockeye salmon have deposits of magnetite in their bodies that enable them to detect the earth’s magnetic field to find their way home.

Wolves have very keen sense of smell and eagles have very sharp sight.

What about the case of people with Synaesthesia (being able to smell sounds or hear colours)?

Five Senses?

The Sense Organs

Anatomy of human eye

Seeing and interpreting

Anatomy of human smell Anatomy of human ear

Consider:

If for some reason you had to sacrifice one of your senses,which one would you be most willing to lose and which wouldyou be least willing to lose? Give reason.

Think of the role played by your observation

in natural sciences in accounts in history in seeing things with new eyes in the visual arts

Seeing and Believing

Biology: 19th C claim of an undiscovered planet Vulcan.

History: 1972 `Bloody Sunday’ in Northern Ireland.

Art: Horses drawn eyelashes in the past.

The rubber hand illusion:http://www.youtube.com/watch?v=sxwn1w7MJvk

Is Seeing Believing?

Based on common- sense realism, perception is a passive and relatively straightforward process which gives us an accurate picture of reality. Colours, sounds and smells exist out there and the act of observation does not affect what is observed.

But there is more to perception than that.

Perception is actually an active and complex process. Rather than our sense passively reflecting an independent reality, our experience of the world is affected not only by what is out there but also by the structure of our sense organs and our minds

Common-sense realism

The process of sense perception is threefold:

First, our sense receptors are stimulated by sensory information.

The brain then translates that sensory information into sensations such as sound, taste, temperature, pressure, smell, or sight...

Finally, higher centres in the brain either ignore or recognise the sensations and their meanings based on neuronal networks of past associations and expectations.

Perception Process

Perceptions can be thought of as consisting of two distinctelements: Sensation provided by the world. Interpretation provided by our minds.

As an important channel communication between ourselves and

the outside world, perception’s function and scope should beexamined and critically evaluated.

Perception Process

Context

Selectivity of Perception

Context

Selectivity of Perception

Context

Selectivity of Perception

Context:

The way we see something tend to depend in

part on the surrounding context.

Selectivity of Perception

Figure and Ground

Selectivity of Perception

Figure and Ground

Selectivity of Perception

Figure and Ground:

We tend to highlight certain aspects (figure)of what we see and treat other parts of it asbackground (ground).

Selectivity of Perception

Visual grouping

Selectivity of Perception

Visual grouping

Selectivity of Perception

Visual grouping

Selectivity of Perception

Visual grouping

Selectivity of Perception

Visual grouping

Selectivity of Perception

Visual grouping

We tend to look for meaning in what we seeand group things into patterns and shapes.

Selectivity of Perception

Expectation

Olny srmat poelpe can raed this. I cdnuolt blveiee that I cluod aulacltyuesdnatnrd what I was rdanieg. Bacuese of the phaonmneal pweorof the hmuan mnid, aoccdrnig to rscheearch at CmabrigdeUinervtisy, it deosn t mttaer in what oredr the ltteers in a word are,the olny iprmoatnt tihng is that the first and last ltteer be in therghit pclae. The rset can be a taotl mses and you can still raed itwouthit a porbelm. This is bcuseae the huamn mnid deos not raedervey lteter by istlef, but the word as a wlohe. Amzanig, huh? Yaehand I awlyas tghuhot slpeling was ipmorantt!

 

Selectivity of Perception

Expectation

Selectivity of Perception

Selectivity of Perception

Expectation

Expectation

We tend to see what we expect to see.

Selectivity of Perception

Context: The way we see something tend to depend in part on the surrounding context.Figure and ground: We tend to highlight certain aspects (figure) ofwhat we see and treat other parts of it as background (ground). Visual grouping: We tend to look for meaning in what we see andgroup things into patterns and shapes.Expectation: We tend to see what we expect to see.

Therefore,There is an important element of interpretation built into

ourperception of the world.

Perception completely free of interpretation is humanly

impossible.

Selectivity of Perception

Selectivity of PerceptionLook at the chart and say the colours, not thewords.

Your right brain will try to say the colours but your left brain will insist on reading the words.

You witness a violent crime. You get a brief glimpse of the assailant?

How sure are you?

Selectivity of Perception

How sure are you?

How sure are you?

How sure are you?

We do not sense all the stimuli that we are potentiallyable to sense. There’s too much going on in ourenvironment for us to handle.

We unconsciously ignore many stimuli, otherwise wewould not survive as a species.

We tend to be more sensitive to stimuli with the followingfactors: Intensity Contrast Moving

Perception and Selection

Subjective factors: Interest: filters which determine what shows up as you scan

the world around you.

Mood: feelings and emotions affect the way we see the world, for example, love and hate.

What we perceive is much affected not just by what is there but by who we are, biologically, personally and culturally.

Perception and Selection

How much of the `real’ world is in our mind?

Is Seeing Believing or Believing Seeing?

Three reasons for caution in relying on perception as

a source of knowledge:

We may misinterpret.

We may fail to notice something.

We may misremember what we have seen.

Perception as an Obstacle to Knowing

The Allegory is related to Plato's Theory of Forms, according towhich the "Forms" (or “Ideas”), and not the material world ofchange known to us through sensation, possess the highestand most fundamental kind of reality. Only knowledge of the“Forms” constitutes real knowledge.

Source: Wikipedia

Plato’s Argument:http://www.youtube.com/watch?v=N3nYAROx1XoPlato - The Allegory of the Cave - (The Matrix) Animated :http://www.youtube.com/watch?v=UQfRdl3GTw4&feature=relate

d

Plato’s Allegory of the Cave

René Descartes

Cogito ergo sum: “I think therefore I am.”

Philosophy and the Matrix - Descarteshttp://www.youtube.com/watch?v=lEr8hnvzeHU

Perception and Reality

Does knowledge come from the senses and experience or would reason be a more reliable source of knowledge?

Perception: Our day-in and day-out world is real?

Reality: That world is a hoax, an elaborate deception spin by all powerful machines that control us?

Matrix: What is Real?http://www.youtube.com/watch?v=WnEYHQ9dscY&feature=related

Are we then to never trust our senses?

Confirmation by another sense: Does it look like an apple AND taste like one? Can you

see the wall AND touch it?

Coherence : Does it "fit in" with your overall experience of the

world?

Independent Testimony: What do other people say? Do they "confirm" your perceptions?

How do we distinguish between appearance and reality in everyday life?

Suppose we evolved sensitivity to a different range of wavelengths, evolved bat-like echolocation, a dog-like sense of smell, an octopus-like ability to alter our skin colour.

What is reality like once we strip away our interpretation and the limits of our sensory apparatus?

Ultimate Reality

Pain

If you burn your hand in a fire, is the pain in your hand or in the fire?

What is really out there?

What is really out there?Taste

If you eat an apple pie, it tastes sweet. Does the sweetness exist in the pie or only in your mouth?

Colour Is the green is no more in the grass as the

sweetness was in the pie? So, if the "green-ness" is merely a result of the

ways our eyes are sensitive to light wavelengths and the physical structure of the grass, does this mean, in effect, the world is colourless?

Reality would then be colourless.

What is really out there?

The Tree in the Forest

If a tree falls in a forest and there is no one to there to hear it, does it make a sound?

If a rose flowers and dies in an uninhabited garden and there is no one there to see it, does it have a colour?

We cannot say that sounds, colours and tastes exist out there independent of our experience of them. So, can anything be said to exist independent of our experience of it?

The Tree in the Forest.

The Tables in the Classroom

Consider the tables in your classroom at school. After you leave the room at the end of the day, how do you know the tables are still there?

Similarly, how do you know the light goes out when you close the fridge door?

The Tables in the Classroom

How do you know?3 theories about the relationship between perception and reality:

Common-sense realism `What you see is what is there.’ The way we perceive the world mirrors the way the world is.

Scientific realism `Atoms in the void.’ The world exists as an independent reality, but it is very different from the

way we perceive it. The familiar, comfortable, sensuous world of our everyday experience

vanishes and is replaced by a colourless, soundless, odourless realm of atoms whizzing around in empty space.

 Phenomenalism `To be is to be perceived.’ Matter is simply `the permanent possibility of sensation’. We cannot know what the world is like independent of our experience of it. We can only know the world from our distinctively human perspective and

have no right to pontificate about the nature of ultimate reality.

Theories of Reality.

Rationalism-An epistemological position in which reason is said to be the primary source of all knowledge. They argue that only reason can distinguish reality from illusion and give meaning to experience. (Descartes)

Empiricism- Belief that all knowledge is ultimately derived from the senses (experience) and that all ideas can be traced to sense data. (John Locke)

What should we believe?

Stick with empiricism and insist that we can know nothing about ultimate reality.

OR

Reject strict empiricism and insist that there is a world out there that is independent of our experience of it.

Choice

Despite sceptical doubts, the existence of the external world is the most reasonable hypothesis to account for the regularity of our experience.

Although perception cannot give us certainty, if the evidence of our senses is consistent with what reason and intuition tell us, it can still provide a good foundation for reliable knowledge.

Conclusion

Our five senses are an important source of knowledge about the world; but rather than passively reflect reality, they actively structure it.

Perception consists of two elements, sensation and interpretation, but we are often not consciously aware of the latter element.

Looking at visual illusions can help make us aware of the role that interpretation plays in perception.

Perception is selective and what we notice in a given environment is influenced by factors such as intensity, contrast, interest, mood and expectations.

The fallibility of perception is relevant to issues in the real world such as eye witness testimony in criminal trials.

We usually distinguish between appearance and reality by using a second sense to confirm the evidence of the first, or by appealing to coherence or the testimony of other people.

The way we experience the world is partly determined by the structure of our sense organs.

If we accept that pain and taste are subjective, we might conclude that colour and sound are also subjective.

There are three main theories about the relationship between perception and reality: common-sense realism, scientific realism and phenomenalism.

Despite skeptical doubts, the existence of the external world is the most reasonable hypothesis to account for the regularity of our experience.

Although perception cannot give us certainty, if the evidence of our senses is consistent with what reason and intuition tell us, it can still provide a good foundation for reliable knowledge.

Key Points

Is there any knowledge that is completely independent of sense perception?

It is often claimed that information and communication technologies are blurring the traditional distinctions between simulation and reality. If this is so, what might be the consequences?

Knowledge issues

“Reality is merely an illusion, albeit a very persistent one."

~Albert Einstein

Perception as a Way of Knowing

Alchin , Nicholas. Theory of Knowledge. London: Hodder Murray, 2006.

Dombrowski, Eileen, Lena Rotenbarg, Mimi Bick. Theory of Knowledge- Course Companion. UK: Oxford University Press, 2007.

Van de Lagemaat, Richard. Theory of Knowledge for the IB Programme. UK: Cambridge University Press, 2005.

Reference