Perception

Front 1

Describe the backdrop to Locke's theory of perception

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Problems of perception arose due to developments in science toward a mechanical account of the world, implying perception should be explained not in terms of something coming from the object to the eye, for instance, but through causal intermediaries like particles or waves that give us perception of objects. Locke's account supposes that the impressions caused in our brain through sensory organs, which we hypothesise to be caused by particles/waves of light etc, with the properties of the particles/waves bearing no resemblance to the objects themselves. Information is conveyed through complex processing. This implies that the intermediary process involves things unlike our mental perceptions/the objects themselves. If you are to think in terms of a mechanical paradigm (best explanation is things bashing into each other) then the best explanation should be in mechanical terms (geometric/dynamic properties) as the crucial causal determinate of what happens. This Corpuscular theory is influential on Locke as it seems closest to an intelligible explanation of how things work. Microstructures (consisting of corpuscles that vary in shape/size depending on substance) of gold are different to those of lead. But this suggests corpuscles are made of the same stuff, universal matter.

Front 2

Briefly explain Locke's theory of substance

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It seems he's likely referring to the same kind of thing (pure substance as opposed to universal matter) as the Corpuscular theory except he doesn't want to commit to the hypothesis. This underlying substance he supposes has primary qualities (shape, size, movement, solidity) that supposedly belong intrinsically to the stuff as well as secondary qualities (colour, smell, taste). the qualities that appear to us are explained by the primary qualities, which are unlike how the thing appears to us. The primary qualities cause the idea of that in us, with the power to produce something in observer. A problem here: speculating about perception leads us to think there nothing like 'redness' in the object. For Locke, the secondary qualities have the powers to produce sensations in us because of their primary qualities. It seems that Locke thinks that secondary qualities are in objects, but secondary qualities in objects are powers.

Front 3

Present Berkeley's misread of his theory

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Berkeley seems to misread Locke's distinction. Being an empiricist, Locke is trying to find a suitable foundation for our knowledge (adequate ideas in the faithfulness of the representation) which leads to his solution: take the simple idea of yellow and ask if that thing is really yellow, if its a faithful representation of what is there. Yes. Simple ideas are certainly adequate because being intent to present nothing but the power in things to produce in the mind such as sensation, it follows that since I see yellow, it has the power to produce something yellow. It causes an idea of yellow in me and thus that is its being yellow/having the power to produce yellow. Simple ideas are thus corresponding the the way things are. It's not in the matter, but a matter of the objects having the quality that produces the idea of yellow.

Front 4

What shift is worth noting at this point?

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Descartes/Locke show a difference in theory. For Descartes, intellect penetrates into the essence of matter to give us perception, whereas Locke bases everything on sensory perception. Berkeley and Hume seem to misinterpret Locke here; it's not that primary qualities are in an object and secondary qualities aren't, but rather the ideas of primary qualities are resemblances of them. Their patterns exist in the bodies themselves. The ideas produced in us through the secondary qualities aren't like them at all. There's nothing like our ideas existing in the bodies themselves. I attribute a property to it, that resembles my idea: roundness of the object. But the yellowness I see is a matter of the microstructure. It is resemblance rather than presence that distinguishes primary and secondary qualities.

Front 5

What is Berkeley's attack on Locke's claim about resemblance:

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An idea cannot resemble an object. An idea can be like nothing but an idea. Ideas are intrinsically perceivable (something about them has to be perceived) which is plausible with secondary qualities. Could the smell of lavender exist outside of the mind? No. Nothing physical can be like a smell as it's intrinsic in the mind, but can the phenomenal look of yellow exist without someone actually seeing it? Berkeley's principle of ideas (as necessarily being perceived) is plausible. But primary qualities (roundness) aren't able to existence without a perceiver; shapes/mathematically abstract properties allow us to think about them in a way that corresponds to the real world. We can imagine an idea and think that if we applied structural thinking it can match up with physical objects in the world. Plausibly, the objects in themselves, though different from our conception, have a structural isomorphism (similar structure) to the way we conceive of them with respect to shape/size.

Front 6

Problem with solidarity:

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I make sense of solidity as a power/behaviour in bodies, but this becomes circular. Hume is critical: two entities cannot exclude each other from their places; what idea do we form of these objects that we believe solidity to belong? 'Solid' ad infinitum. Extension must necessarily be considered as coloured (a false idea/secondary quality) or as solid (circular).

Front 7

Does this attack on resemblance invariably lead us to an attack on our lack of understanding?

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Naturally, we have a lack of understanding the qualities concerned leading to a further attack. Empiricism insists that all our ideas come from/are copies of experience. Berkeley/Hume both follow him on this, but if our ideas are copied from experience, it seems that our ideas of primary qualities must be infused with the experiential qualities through which we experience them: I see a circular shape necessarily with colour. Why then, does it not follow that my idea of a shape must intrinsically be coloured? If secondary qualities cannot exist outside of the mind, is it not also true of primary qualities? Why can't I form the abstract idea of a circle without colour through experiences of variously coloured circles? That idea of circularity isn't going to be contaminated with subjective secondary qualities after all (Locke). Berkeley/Hume attack this doctrine of abstraction (forming general ideas by leaving out details/retaining features) as it is inconsistent/cannot exist in reality; imagine a man through this method. This is important because of its link to primary/secondary qualities: Berkeley wants to say that I cannot form the idea of a circle which has no colour/the idea of a primary quality (circle) without the secondary quality colour (yellow/intrinsically mental) then I cannot form the conception of a primary quality that can exist independently of the mind. Bodies beyond the mind are inconceivable: the world exists entirely from mental entities, hence Berkeley's idealism.

Front 8

Provide some compromise on this attack on perception.

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It would seem necessary to concede that our notion of body is unlikely to be ultimately composed of elements that we entirely understand in the terms that Locke thought we could. If we try to form an idea of body as consisting entirely of properties that resemble our ideas, we have a problem understanding what it is that fills this space. We have to attribute bodies as having something 'I know not what'. Is this a problem?

Front 9

Why is/isn't this a problem?

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With modern science, this is familiar. The properties we use to explain matter are those that are intelligible to us. Solidity shows this not to be so simple. The distinction between matter/empty space needs to attribute the crucial quality of solidity or something like it, which we can only understand indirectly in dispositional terms (keeping something out of I don't know what). Charge, spin and other properties attributed to fundamental particles leads us to quantum mechanics which gives up most if not all the ideas we have of intelligible properties/qualities. Our senses are naturally fitted to understand the world at one level but that doesn't mean that our intuitive understanding it going to work all the way down. We may have to accept that our best theories are going to attribute fundamental properties to objects that are radically different to our intuitive awareness. Something I know not what has these properties. (A solid defence of realism as long as we relax the requirement of intelligibility).

Front 10

Present another attack of realism:

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Locke's indirect realism: I directly perceive the tree and I assume there is a material object that is the cause of this idea (incurring the veil of perception problem: how do we know that there really is a material object beyond this veil) It can seem to do so particularly if the‘Unacceptable Interpretation’ tempts you. You can parody indirect realism bypostulating an idea of a tree in my mind. I see the tree by seeing the idea inmy mind through a little man behind a screen. What does this amount to? Thisisn’t explanatory; its explaining perception of the tree with perception of theidea of the tree which replaces one mystery with another.

Front 11

What is wrong with that?

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That interpretation is clearly wrong which naturally leadsto following puzzle: the image of the tree is upside down in the retina. Why isthis so puzzling? The projection of thatimage onto the retina is just is part of the process of seeing (through anintricate mechanism). We are aware of the tree by means of this physicalprocess. When we read about sense data there is a temptation to view it interms of the unacceptable interpretation. It’s better to say that awareness ofthe sense datum counts as perception of an external object. It’s not that youperceive a sense datum and thus perceive an external datum, but you are awareof the sense datum. But how can we know that there really is an object beyondour immediate awareness? How do we prove a causal link?

Front 12

What does Hume claim?

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Hume claims: once you accept that there is adifference between you object out there and your perceptions, how do we knowthat there are any objects there. We’re only directly aware of thoseperceptions; how can we ever establish a reliable causal connection between thesupposed object and our perceptions if we are only acquainted with our ownperceptions?

Front 13

What might one say in defence of such a claim?

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Phenomenalism is the view that physical objects are logicalconstructions out of sense data, statements about physical objects are tointerpreted as statements about sense data. What you would perceivecorresponding in certain circumstances. This attempts to get round theBerkelian argument (you can’t make sense of physical objects in abstractionfrom perceptions) and this account attempts to analyse this and the veil ofperception. If I am acquainted with my own perceptions and if physical objectsjust are to be analysed in terms of my own perceptions then it seems we can getaround vertical scepticism (if we can’t prove the existence of the physicalobjects, let us analyse those in terms of what we do know, our ownperceptions). Horizontal scepticism can be raised just as effectively: theproblem of induction. Justifying the claim of the predictions as being true isa problem. Instead of being direct realism (perception through ideas) it shouldbe said that we perceive objects directly. In one sense it seems right(counters the unacceptable interpretation) however, there is no question thatmy seeing the tree is mediated by a physical process (light, optic nerves/thebrain) but that doesn’t help the sceptical problem (the experience you’rehaving: how do you know it is caused by the perception of the tree?). It givesa verbal solution rather than a genuine one.

Front 14

Back to Locke's position

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Back to a Lockean position that accepts thedifference between the object itself and how the object appears to us(accepting sceptical problems) that it is possible to distinguish one from theother and is thus a logical possibility of the tree being there without meseeing that it is there. To get rid of the unacceptable interpretation, thinkof the idea as an intentional object (not a little tree in the mind, but how atree appears to me): when I perceive a tree, there is a characteristicexperience of what it is like to perceive a tree. Distinguishing thisexperience from the actual being of a tree, talk of the idea of a tree is justthat (what its like to see a tree). We end up going back to indirect realism ina sense: not saying there are little ideas that are intermediaries, butreflecting the fact that when we perceive objects there is an experience ofwhat it is like perceiving that object, you can draw a conceptual distinguishbetween our awareness of them and the existence of them.

Front 15

What is the justification for this?

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Justification: their scientific explanation (how thingsappear to us is explicable in terms of mechanism that attribute causal powersto these objects, explained through intermediaries like sound waves etc) thatallows us to predict how these things behave. Corresponding qualities (shape)allow us to predict things better. It is more plausible then (rather thanBerkley’s God) to suppose that there are really structurally things like ourconceptions of them. Causal explanations of how things behave/bring about ourperceptions are going to have to be in terms of the objects real qualities, butwe can drop the requirement that these must resemble our ideas.