ithout being blended, then there must be edges between them, and shapes outlined by those edges. Condillac accepted that this would in fact be the case. But he denied that his “statue” would necessarily have to be aware of this fact. The “statue” would need some reason to turn its attention to the boundaries between colours, to identify the various parts of those boundaries, and to notice what shape they constitute. But if it only considered colour sensations to be its own states of being, and took pleasure or pain only in their chromatic qualities and not in their shapes (a rather large presumption that Condillac seems not to have realized making), it would have no reason to notice that colours have shapes or even that they have particular locations relative to one another. Consequently, even though it would experience colours as being extended and outside of one another, it would not notice that the array of simultaneously present colour sensations forms an unbroken continuum. It would experience its coloured self merely as an aggregate of distinct extensions, vaguely perceived as not having any definite boundaries or shapes, and not recognized as having any locations relative to one another. Consequently, it would have no developed concept of space (Treatise I.xi.8–9).
Condillac maintained that it is only through the sense of touch that a being first acquires an awareness of space as an external continuum extending outwards beyond the bounds of its body, and an awareness of other objects in this space. Touch then teaches us to attribute smells, sounds, tastes, and colours to external objects.
Like Thomas Reid, who some ten years later also set about investigating what each of the senses can lead us to learn, Condillac took the tactile sensation of solidity to be crucial for the development of an awareness of space and of external objects. Only whereas Reid maintained that we are innately so constituted as to understand the purely qualitative sensation of solidity as sign signifying a quality of external objects, Condillac attempted to explain how experiences of the sensation of solidity could put us in a position to infer that we have spatially extended bodies and that something else exists outside of our bodies (Treatise II.v).
These inferences arise as a consequence of the comparison of two cases, one where a being touches itself, the other where it touches something else. A being that touches itself experiences a sensation of solidity in its hand and an “answering” sensation of solidity in the part of its body that it touches, thereby experiencing itself as being solid, as being two instances of solidity, and as being two instances of solidity outside of one another. Were the being to lift its hand from its body and touch another part of its body, the pair of these sensations would cease and then after a time one member of the pair would recur in the company of a different partner. The being would experience a new sensation of solidity outside of the one it receives from its hand, but its awareness of the different body parts that it touches would be like its awareness of colours. Though experienced as being outside of one another, the touched body parts would not be experienced as forming a continuum or as spatially related to one another. However, were the being to move its hand over its body without lifting it, it would experience a continuous sequence of sensations of solidity arising from different body parts. Moving the hand repeatedly in the same way would always produce the same series of sensations. Condillac did not go into any more detail, but he seems to have presumed that this would be enough to warrant the inference that the touched body parts coexist and form a continuum. Thus, through moving its hands over itself, the “statue” is supposed to acquire an awareness that it has a spatially extended body.
When the “statue” touches another object, it experiences only one sensation of solidity without the answering sensation. The absence of the second sensation is supposed to induce the judgment that there