Direct Realism Criticisms

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Presentation transcript:

Direct Realism Criticisms 1. Understand the main responses to Direct Realism. 2. Explain how these responses invalidate the argument. 3. How successful have these responses been in their refutation?

Direct Realism With your partner: Quickly explain the main idea behind direct realism in less than 20 words. Then explain how a direct realist would see a tree in less than 15 words.

Criticism 1: The Argument from Illusion P1: I have a straw, which appears to me to be straight, but when it is half submerged in water it seems to bend and distort. P2:I know that the straw is straight and that its apparent flexibility is a result of its being seen through the water. IC: Yet I cannot change the mental image I have of the straw being bent. C: Since the stick is not in fact bent its appearance can be described as an illusion. I am seeing the straw indirectly.

Criticism 1 Cont. On occasion when we perceive an object it appears to be one thing when in reality it is another. The conclusion is drawn that what we immediately perceive cannot be what is in the world, since what we are perceiving is not the same as what is really there. Therefore errors of perception only occur when I make judgments on the basis of sense data concerning what causes them.

Criticism 1 Cont. As a result the argument from illusion demonstrates that we perceive mind-independent objects indirectly. How could a Direct Realist respond? Which part of Direct Realism is this argument attacking?

Exam Q Practice Explain the argument from illusion in response to Direct Realism (5) AO1 5 A full, clear and precise explanation. The student makes logical links between precisely identified points, with no redundancy. 4 A clear explanation, with logical links, but some imprecision/redundancy. 3 The substantive content of the explanation is present and there is an attempt at logical linking, but the explanation is not full and/or precise. 2 One or two relevant points made, but not precisely. The logic is unclear 1 Fragmented points, with no logical structure. 0 Nothing written worthy of credit.

Replies to Criticism 1 from a DR Our senses do accurately reflect the world we simply misinterpret what we perceive. The argument from illusion assumes that if we misperceive something then we must perceive something distinct from reality i.e. we are not directly perceiving the external world. However DR responds by stating that we are simply misperceiving reality – there is not something distinct or separate from reality. As such we ‘can perceive a straight straw as bent without implying that we directly perceive a bent straw and only indirectly a straight one.’ Referring to the straw in water, DR argues that when the straw is in the water it looks bent and distorted but there is nothing that is bent and distorted in reality. There is a difference between the property ‘being bent’ and the property ‘looking bent’. Either way we directly perceive the physical objects and their properties.

Are these responses successful? Rate the responses out of 10. Are they successful in their refutation of Direct Realism.

Criticism 2: The Argument from Perceptual Variation “It is evident from what we have found, that there is no colour which pre-eminently appears to be the colour of the table, or even of any one particular part of the table – it appears to be of different colours from different points of view, and there is no reason for regarding some of these as more really its colour than others…This colour is not something which is inherent in the table, but something depending upon the table and the spectator and the way the light falls on the table…” Bertrand Russell, The Problems of Philosophy

Bertrand Russell Can you outline the argument in its premise form?

The Argument P1: There are variations in Perception P2: Our perception varies without corresponding changes in the physical object we perceive. (For instance, the desk remains rectangular, even as the way it looks to me changes as I look at it from different angles.) IC1: Therefore, the properties physical objects have and the properties they appear to have are not identical. IC2:Therefore, what we are immediately aware of in perception is not exactly the same as what exists independently of our minds. C: Therefore, we do not perceive physical objects directly.

Clear?! The Argument from Perceptual Variation argues that as there are variations in our perception of physical objects – such as shape, texture and colour – we cannot perceive mind-independent objects directly. The argument from perceptual variation in simple terms: the way we see the object changes, but the object does not change itself. Therefore we perceive objects indirectly.

A Table! The appearance of the table changes according to each point of view. But the reality of the table existing in the external world does not change.

Sense Data is the name that Russell gives when discussing the appearance of an object. “If we take any common object of the sort that is supposed to be known by the senses, what the senses immediately tell us is not the truth about the object as it is apart from us, but only the truth about certain sense-data which, so far as we can see, depend upon the relations between us and the object.” Bertrand Russell

Sense Data This is the name of what we are immediately aware of in perception. ie. The colour and shape of the desk as we see it now.

So how good is this criticism? Rate it between 1 and 10. Why have you placed it where you have? Explain Bertrand Russell’s objection to Direct Realism (5)

Replies to Criticism 2 Although we may not perceive the world precisely as it is, does not imply that we don’t perceive it directly  what varies is not what we see, but the way in which we see it.

In perception we are aware of a range of properties: ‘some of which the object has independent of our minds, and some of which it has in relation to being perceived.’ For example, a rectangular desk has the property of ‘looking obtuse’, which is distinct from the property of ‘being obtuse’. A DR would argue that the rectangular desk – which we know to be rectangular from prior knowledge through science and mathematics – can be both rectangular and look obtuse. DR can further defend itself through the concept of a relational property – the property of ‘looking obtuse’ is a relational property because the desk has this property in relation to me when it is a certain distance, angle etc from me. Therefore DR can claim that what we perceive are physical objects and not sense data, as it does not have to claim that all their properties, as we perceive them, are mind-independent.

Criticism 3: the Argument from Hallucination The Argument from Hallucination argues that our perception is susceptible to hallucinations, both visual and auditory. Therefore when we are hallucinating we perceive something or something having a particular property. Why – Because a hallucination is believed to be real by the perceiver. (See Macbeth’s example with the dagger!) This means that during a hallucination it is impossible for me to distinguish my experience from genuine perception (veridical perception i.e. I perceive something that is true or an experience that represents the world as it really is).

However! a hallucination is an experience involving the apparent perception of something that is not actually present. Therefore we don’t perceive the object at all! This attacks DR as what a hallucination is, is sense data and never a mind-independent physical object. See argument – using Macbeth’s dagger – below:

Macbeth R1. When Macbeth has his hallucination of a dagger, there is something that he sees before him. R2. The thing he sees is not a physical object. C. So it must be a mental image (i.e. sense data).

Replies to Criticism 3 One can identify when we are hallucinating. i.e. use other senses to determine that we are hallucinating. Deny hallucinations are really perceptions at all. i.e. we are simply imagining something which is not the same as perceiving sense-data. To imagine something is not to perceive it.

Criticism 4: The Time Lag Argument The Time-Lag argument argues that what you see is not how the physical world is, because it takes time for sound and light to travel from the physical object to your senses. This attacks DR as it suggests that we do not directly perceive the objects around us. Russell observes a similar problem: ‘It takes about eight minutes for the sun’s light to reach us; thus, when we see the sun we are seeing the sun eight minutes ago…if the physical sun had ceased to exist within the last eight minutes, that would make no difference to the sense data which we call ‘seeing the sun’.’ Bertrand Russell, The Problems of Philosophy, Chapter 3

Time Lag Argument R1. If the sun had just winked out of existence, there would still be something that I see when I look in its direction. R2. This thing cannot be the sun, since the sun would no longer exist. C. So it must be an image of the sun – i.e. a sense datum.

Replies to Criticism 4 DR can accept that there is a time lag in perception, but can deny this implies that we don’t directly perceive physical objects or that we must introduce something different i.e. sense data. All that follows is that we perceive objects as they were, not indirectly.

Homework for Half-Term Answer the two (9) mark questions given on the worksheet. Research Indirect Realism and write a brief response and upload to Kaizena. Have at least 3 entries into the extra-reading spreadsheet.