Berchielli’s interpretation

Let us now turn to the second alternative interpretation, according to which Locke thinks that three-dimensional shapes are delivered by visual perception in a passive manner. Let us first deny that Berchielli gives proper evidence, and then argue against her interpretation.

Berchielli begins with drawing our attention to Locke’s remark that sight is ‘the most comprehensive of all senses’.25 Locke’s reason for this claim, according to Berchielli, is that sight ‘has access to figures that the sense of touch cannot reach’.26 Berchielli holds that Locke thus gives primacy to sight. She regards this as Locke’s ‘first step’ towards the view that we passively have visual experience as of three- dimensional shapes.27I will not argue against this point, because Berchielli would admit that Locke’s endorsement of the comprehensiveness of sight does not serve as sufficient evidence for his taking visual experience as three-dimensional, being only the ‘first step’.

Berchielli’s substantial evidence rests on what Locke says concerning the idea ofspace. The outline of her argument is as follows. Locke defines shape as a ‘mode’

of the simple idea of space. The simple idea of space, according to Locke, is received by both sight and touch. He regards the simple idea of space as an idea of three- dimensional space. Therefore, an idea of shape, which is a ‘mode’ of the simple idea of space, should be an idea of three-dimensional shape, whether it is perceived by sight or touch. Let us closely look at this argument in what follows.

25

Ibid., II, ix, 9, p. 145.

26

Berchielli (2002), p. 54.

27

Locke discusses ‘modifications’ of one simple idea, or ‘simple modes’, in Book II, xiii.28The mind passively receives a simple idea. According to Locke, the mind, by repeating a single simple idea, can obtain further ideas, which ‘the mind either finds in things existing, or is able to make within itself’.29He, as we have seen, takes space as one of the simple ideas received by both sight and touch. One of his examples of simple modes of the idea of space is the idea of figure. Locke writes:

There is another modification of this idea [of space], which is nothing but the relation

which the parts of the termination of extension, or circumscribed space have amongst

themselves. This the touch discovers in sensible bodies, whose extremities come within

our reach; and the eye takes both from bodies and colours, whose boundaries are within

its view: where observing how the extremities terminate either in straight lines, which

meet at discernible angles; or in crooked lines, wherein no angles can be perceived, by

considering these as they relate to one another, in all parts of the extremities of any body

or space, it has that idea we call figure, which affords to the mind infinite variety. For

besides the vast number of different figures, that do really exist in the coherent masses of

matter, the stock that the mind has in its power, by varying the idea of space; and thereby

making still new compositions, by repeating its own ideas, and joining them as it pleases,

is perfectly inexhaustible: And so it can multiply figuresin infinitum.30

One of the modifications of the simple idea of space is the idea of figure. The mind discovers the relation among the parts of the termination of perceived extension – i.e. the relation among the parts such as straight lines and curved lines. The mind thus ‘finds in things existing’ their shapes. If the mind finds three straight lines being the boundaries of extension, for example, it thereby has the idea of a triangle.

28

Locke (1997), II, xiii, 1, p. 162.

29

Ibid.

30

Furthermore, the mind, through repeating such parts as straight lines and curved lines, can ‘make within itself’ the ideas of infinitely many shapes. Berchielli construes that Locke, in the above passage, gives the definition of shape – i.e. the definition of shape as a mode of space.31

Berchielli, then, turns to the ideas of ‘distance’ and ‘capacity’, of which Locke writes as follows:

This space considered barely in length between any two beings, without considering

anything else between them is called distance: if considered in length, breadth, and

thickness, I think, it may be calledcapacity… .32

‘Distance’, which is one-dimensional, and ‘capacity’, which is three-dimensional, are kinds of the idea of space. (This discussion is followed by a section in which Locke claims that the ideas of different distances, such as an inch, foot, yard, etc., are different modifications of the idea of space, or the idea of distance.33) Berchielli stresses that the idea of space, for Locke, can be that of ‘capacity’, which has three dimensions.34 If the simple idea of space can thus be considered in a three- dimensional way, then it follows that the simple idea of space given to sight (as well as to touch) is that of three-dimensional space. Since an idea of shape is defined as a modification of this idea of space, an idea of shape would be that of three- dimensional shape.

I disagree with Berchielli’s interpretation that Locke isdefining shape when he

holds that an idea of shape is one of the modes of the idea of space. For modes are classified by Locke as complex ideas, which the mind actively frames by using as

31

Berchielli (2002), p. 55.

32

Locke (1997), II, xiii, 3, p. 162.

33

Ibid., II, xiii, 4, p. 162.

34

materials simple ideas received passively.35Thus, when Locke says that the mind obtains an idea of shape by ‘observing’ the termination of extension and ‘considering’ the relation of its parts, or by repeating the idea of space, the mind is thought to be engaged in anactivityof forming a complex idea. In other words, when Locke holds

that an idea of shape qua a modification of the idea of space is ‘nothing but the

relation which the parts of the termination of extension … have amongst themselves’, he is explaining an idea of shape quaa complex idea, which is an idea of shapequa

an idea of a relation among lines. In contrast, we saw that Locke includes an idea of shape among simple ideas received passively.36 A simple idea of shape received either by sight or by touch is obviously not a modification of space, or the idea of space actively formed as a relation among lines. There are two ways in which the mind can have an idea of shape; one way is to passively receive it by sight or touch, and the other way is to actively form it as a mode of the idea of space. Therefore, Berchielli is wrong in construing Locke as defining an idea of shape as a mode of the idea of space. Rather, he is talking of one of the two ways in which the mind can have an idea of shape.

Berchielli might insist that linking an idea of shape to the idea of space is not necessary for her interpretation. Locke says that the idea of space is received by sight, and also that the idea of space can be the idea of capacity, which has three dimensions. Would it not follow from this that our visual perception is as of three- dimensional space? I think not. Locke only holds that space considered in terms of one dimension is ‘distance’ whereas space considered in terms of three dimensions is ‘capacity’. He does not say that the idea of space received by sight and that received

35

Locke (1997), II, xii, 1, p. 159; II, xii, 3, p. 160. Locke classifies complex ideas into three kinds, which are ‘modes’, ‘substances’ and ‘relations’.

36

by touch can both be considered in terms of three dimensions. He could claim that the idea of space received by sight does not allow us to have the idea of capacity, whereas the idea of space received by touch does.

According to Berchielli’s interpretation, Locke takes three-dimensional shapes to be delivered by sight in a passive manner. I have shown that her evidence fails to support her interpretation. She also reconstructs Locke’s view on how three-

dimensional shapes are delivered by visual experience, admitting that Locke is not explicit on this matter. I would now like to reject her reconstruction of that view. According to Berchielli, Locke thinks that visual experience as of a three- dimensional shape is a temporal process – that it is a process that takes time. For example, if we are shown a cube only instantaneously, the idea we receive without judgement would be an idea of a two-dimensional shape (such as a hexagon). But if we are allowed to look at a cube from many points of view, the cube rotating in front of our eyes, or us moving around the cube, we would be able to have an idea of a cube even without a judgement. Visual experience as of a three-dimensional shape, thus, is possible if there is time for the subject or the object to move in relation to the other.37

Berchielli goes on to insist that Locke would therefore give a positive answer to Molyneux’s Question if he considered a case where Molyneux’s subject is allowed to look at the cube and the globe from many points of view. The reason is that Molyneux’s subject, under this condition, could have visual perception as of three- dimensional shapes, even though he has not learned to make a judgement to obtain ideas of three-dimensional shapes. It would be that Molyneux’s subject could have visual experience as of a cube and a globe in a passive way. According to Berchielli,

37

Locke gives a negative answer because his supposition is that there is no movement of the subject or the objects. If there is no movement, Molyneux’s subject could only receive ideas of two-dimensional shapes.38

Berchielli says: ‘In my model, the material impressions of sight in Locke are not (instantaneous) retinal images, but rather a succession of images’.39 Receiving an idea of shape through sight is a temporal process because an idea of shape results from ‘a succession of images’. However, if an instantaneous image as visually experienced is two-dimensional, how could a succession of images be three- dimensional? It seems to me that some mental activity would be required for a series of flat images delivered to the mind to produce an idea of a solid shape. I do not mean that the mind would need to be active in order to obtain a single idea through temporally extended experience; there might be no need for the mind to actively collect a series of images delivered by sight. (Indeed, Locke allows that there is a simple idea of motion, the possession of which would require unity of successive instantaneous experiences.) Nor do I simply assume that the mind would have to be active in order to obtain an idea of a three-dimensional shape; it is possible that solid shapes are passively delivered by visual perception. My point is as follows: if, as Berchielli says, Locke’s view is that an instantaneous visual perception can only deliver a two-dimensional shape, then that view would be incompatible with the account that a three-dimensional shape is delivered by visual perception in a passive manner in cases where a solid object is viewed from many angles. If Berchielli were right, it would follow from Locke’s view that we passively see three-dimensionally when, say, a cube rotates in front of the eyes. However, even on her interpretation, if

38

Ibid., pp. 62-4.

39

an instantaneous experience is isolated from the temporal succession of visual experiences, it would be as of a two-dimensional shape. For example, on Berchielli’s interpretation, visual perception I have by looking at a cube from obliquely above would be as of a three-dimensional shape if the perception is part of the temporal succession, whereas perception I have by looking at a cube from precisely the same angle would be two-dimensional if it is not part of the succession, i.e. in a case where there is no movement. That is, the objective (or physical) state of affairs at one moment, i.e. the objective (or physical) relation between the object and my eyes obtaining at one moment, would not determine whether the shape as visually perceived at that moment is two- or three-dimensional. The implication would be that there is some contribution by the subject that explains the spatial dimensionality of the shape as seen at the instant in question. Berchielli does not provide a coherent interpretation in insisting that the mind, for Locke, could passively have visual experience as of a three-dimensional shape in cases where the object or the subject moves.

Indeed, Berchielli takes Locke’s remark on ‘observing’ and ‘considering’, which I have quoted above, as a clue to understand Locke’s inexplicit view as to how we see three-dimensionally. According to Berchielli, Locke thinks that we have visual experience as of three-dimensional shapes by ‘observing’ a temporal series of boundaries of colour and ‘considering’ the relation among them. Berchielli takes this process to be passive.40 However, as we saw, an idea we obtain as a result of ‘observing’ and ‘considering’ is, for Locke, a complex idea; it is a ‘mode’, which is formed actively.41Therefore, we have to construe the processes of ‘observing’ and

40

Ibid., p. 58.

41

‘considering’ as active ones through which the mind frames a complex idea of shape. ‘Observing’ and ‘considering’ are irrelevant to Locke’s view on what ideas the mind receives by perception prior to a judgement or other mental activity. So, from Locke’s remark on ‘observing’ and ‘considering’, Berchielli could not draw the account that we have experience as of a three-dimensional shape in a passive manner.