And why is it, that on a subject of this nature the manifest facts witnessed in the whole animal creation are to be overlooked? If other animals evidently, on the first opening of their eyes, see form, and movement, and the whole world before them; does not this sufficiently intimate the instantaneous knowledge which it is the nature of vision to bestow? The human infant arrives, indeed, more slowly at the perfect use of its senses. It arrives, also, more slowly at the perfect use of its limbs. But we never conclude because it does not rise and skip about the fields like a dropped lamb, that there is any essential difference between its muscular powers and those of other animals of creation. Why should we suppose that its vision is regulated by different laws merely because it obtains the perfect use of its eyesight somewhat later? Let us now turn from the imperfect analysis which the _sensational_ school presents, to the speculations of the _idealist_. It will be seen that the hasty conclusions of the first gave a sort of basis for the strange results to which the second would conduct us. Kant looked in vain for the idea of extension, or of space, where the philosophers had been seeking it, in the phenomena of sensation. He pronounced, therefore, that it was not derivable from experience, did not come to us from without, through any direct communication from the senses. Not finding this idea of space where the analytical psychologist had been searching for it, he drew it at once from the mind itself. He described it as a product of the _subject_ man, a _form of the sensibility_ with which he invests his own sensations. We must first remark, that to this description of what perception really is, there lies the same objection that may be urged against the account of the sensationalist. A sensation clothed in space!--is this intelligible? is it by any means an account of the matter? To invest sensation with space, is it not as if we spoke of a _pleasure_ that was _square_, or of a _circular pain_? So far, however, as this internal origin of the idea of space is concerned, the statement of Kant, though expressed in unusual terms, is not opposed to the general belief of mankind, or to our irresistible convictions. It may merely convey this meaning, that the mind has an immediate knowledge (drawn from the laws of its own cogitation) of space, or extension. But then, according to the universal and unalterable convictions of mankind, this idea of space, though it may be derived from the innate resources of the mind, is in fact the knowledge of an external reality--of an _objective_ truth. Kant decided otherwise. He pronounced this _form of the sensibility_ to be merely and only a mode of thought--that space had, in fact, no other existence, was solely a _subjective_ truth.