Knower(s)

Natural Sciences

Language

SensePerception

Emotion

Reason

Mathematics

Human Sciences

History

Arts

Ethics

Ways of Knowing

Areas of Knowledge

Theory of Knowledge Diagram

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Empiricismstarting point for all knowledge is experience

Rationalismstarting point for all knowledge is reason

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Sense Perception and Knowledge

Our senses connect us with the world around us …

… but how connected are we?

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Cosmic RaysX Rays

UV LightInfra Red

RadarTV & Radio

Frequency (Hz)

Visual Window

10 22 1020 1018 1016 1014 1012 1010 108 106 104 102 100

Our senses are limited: Light Waves

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Highest Voice

Frequency (Hz)

Audio Window

10 22 1020 1018 1016 1014 1012 1010 108 106 104 102 100

Lowest Voice

Our senses are limited: Sound Waves

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Bloodhound: “A nose with a dog attached”

• 230 million olfactory cells compared to 5 million in humans

• 1000 times better sense of smell than humans

• Have been known to be able to track a scent for over 100 miles

Our senses are limited: Smell

So perhaps we don’t see, hear, smell, taste and touch everything…

… but what we do sense, we sense accurately – don’t we?

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Think about physical sensation (Touch)….• You plunge your hand into a bucket of hot

water – is the pain in your hand, or in your mind?

• You plunge your hand into a bucket of ice cold water – for a moment you aren’t sure if it is hot or cold …

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What is in the mind and what is in the world?

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Sensation which is provided by the world

Interpretation which is provided by the mind

(external stimuli + mental processes)

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Esref Armagan – born blind

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In our everyday life, we are not usually aware of our minds

interpreting the sensations that flood into our senses ....

Awareness test - Selectivity

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Sensory Perception is selective: What the eye saw….

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Sensory Perception is selective: What the camera saw….

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Donna Williams – author and consultant

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“It’s not what you look at that matters, it’s what you see.”

H.D. Thoreau

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Interpretation: Understanding what we see - Coherence

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Expectation

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Expectation

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What is this?

Organising Principles – the Law of Simplicity

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What is this?

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Interpretation – finding meaning in what we see

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Interpretation

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Imagination, Context,

Expectation andSense Perception

affect the way we interpret sense data

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You are walking down a dark alley ... there are footsteps behind you …

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Context

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The mental construction of reality

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The two tables are exactlythe same length and width

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“The eyes see only what the mind is prepared to

comprehend”Bergson

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Take the following and explain how education and training can affect what we perceive:

• A biologist looking down a microscope• A dentist looking at an x-ray• A professional wine taster• A lifeguard• An artist

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“Who you are decides what you see”

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Think about the following and describe how they might be seen through the eyes of the

different people:

1. A child dying in poverty as seen by a doctor, an economist, a social worker, the child’s father

2. A sunset as seen by a religious figure, a physicist, a painter, a farmer

3. A tree as seen by a biologist, a logger, an environmentalist, a carpenter

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Sense Perception is an important source of knowledge but there are reasons for treating it with caution:

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• We may misinterpret what we perceive• We may fail to notice something• We may misremember what we have

perceived• Sensory perception is selective• Our senses have limitations• Experience creates expectations• Subjective factors – interests, moods –

affect sensory perception

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Eye-witness testimony

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Person Swap - Expectation

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Some key points:

• Sense perception consists of Sensation and Interpretation

• If we accept that pain and taste are subjective, we might conclude that color and sound are also subjective

• Senses are an important source of knowledge but rather than passively reflect reality, they actively structure it

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Some more key points:

• Sense perception is selective• Sense perception has limitations• Although sense 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

Some safeguards:

• Confirmation by another sense

• Coherence

• Independent testimony

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Perception

LanguageHow does the

way we describe something affect the way we see

it?

ReligionWhat role does

perception play in religious

experience?

EthicsDo good people

see the world differently from bad people?

ArtsTo what extent do the arts help us to see the world with

new eyes?History

Should we trust eyewitness testimony?

Human Sciences

Does observation influence what is

observed?

MathsDoes perception play any role in Mathematics?

Natural Sciences

Do expectations influence

observations?

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Some Knowledge Issues

• What factors affect our ability to gain knowledge through the senses?

• How do our senses hinder us in our attempts to gain knowledge?

• How is sensory perception affected by emotion/reason/faith/language?

• How do context and culture affect our perceptions?

• When you are told that ‘you should be more objective’ – what does that mean?

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ToK Prescribed Essay Title: 2008

“When should we trust our senses to give us truth?”

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Common sense realism: the way we perceive the world mirrors the way the world is

Scientific realism: the world exists as an independent reality but it is different from the way we perceive it

Phenomenalism: it makes no sense to say that the world exists independent of our experience of it. “To be is to be perceived” (Are the chairs in the classroom when you aren’t there?)

See ‘Theory of Knowledge for the IB Diploma’ Richard van der Lagemaat, p 99-101

Extras

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Finished files are the result of years of scientific study combined with the

experience of years

How many times does the letter ‘f’ appear in this sentence?

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