does not say by any means that it is not open to criticism. On the contrary, there is a great deal to be said against it, and, in fact, they are very, very weighty objections which have been brought against it. The assumption of the ideality of space and time in the Kantian sense led to inextricable contradictions.
There can certainly be no doubt that our conceptions of time and space are conditioned by the constitution of our faculties of knowledge, but I should have thought that that would only necessarily amount to saying that only those connections of events in the universe can be recognised which are of such a nature as to call forth in our intellectual faculties the concepts of space and time. The ideality of time and space would then imply, just as the thing itself, no more and no less than a limit to our powers of knowing. Relations of a kind which cannot take the form of space or time concepts—even if such really exist, which we do not know—are for us inconceivable, just as much as the ultra-violet and ultra-red rays are imperceptible to our powers of vision.
But this was by no means the sense in which it was understood by Kant. Because space and time provide the forms in which alone our faculties of knowledge can recognise the world, he takes for granted that time and space are forms which are only to be found in our faculty of knowledge, and correspond to no sort of connection in the real world. In his "Prolegomena to every future Metaphysic," Kant compares in one place the concept of space with the concept of colour. This comparison appears to us very apt; it by no means, however, proves what Kant wants to prove. If cinnabar appears red to me, that is certainly conditioned by the peculiarity of my visual organs. Outside them there is no colour. What appears to me as colour is called forth by waves of ether, of a distinct length, which affect my eye. Should anyone wish to treat these waves in relation to the colour as the thing in itself, which in reality they are not, then our power of vision would not be a power to see the things as they are but power to see them as
