Chapter I (part 3)

______ Since the remotest antiquity the question of our relation to the true causes of our sensations has constituted the main subject of philosophical research. Men have always felt that they should have some solution for this question, some answer for it. And these answers have vacillated between two poles, from the full negation of the causes themselves, and the assertion that the causes of sensations are contained within ourselves and not in anything outside of us—up to the recognition that we know these causes, that they are embodied in the phenomena of the outer world, that these phenomena constitute the cause of sensations; and that the cause of all observed phenomena lies in the movement of "atoms," and the oscillations of the "ether." It is believed that if we cannot observe these motions and oscillations it is only because we have not sufficiently powerful instruments, and that when such instruments are at our disposal we shall be able to see the movements of atoms as well as we see, through powerful telescopes, stars the very existence of which were never guessed. ______ p. 15 In modern philosophy Kant's system occupies a middle position in relation to this problem of the causes of sensations, not sharing either of these extreme views. Kant proved that the causes of our sensations are in the outside world, but that we cannot know these causes through any sensuous approach—that is, by such means as we know phenomena—and that we cannot know these causes, and shall never know them . Kant established the fact that everything that is known through the senses is known in terms of time and space, and that out of time and space we cannot know anything by way of the senses; that time and space are necessary conditions of sensuous receptivity (i.e., receptivity by means of the five organs of sense). Moreover, what is most important, he established the fact that extension in space and existence in time are not properties appertaining to things , but just the properties of our sensuous receptivity; that in reality, apart from our sensuous knowledge of them, things exist independently of time and space; but we can never perceive them out of time and space, and perceiving things and phenomena thus sensuously, by virtue of it we impose upon them the conditions of time and space, as belonging to our form of perception. Thus space and time, defining everything that we cognize by sensuous means, are in themselves just forms of our receptivity, categories of our intellect, the prism through which we regard the world—or in other words, space and time do not represent properties of the world, but just properties of our knowledge of the world gained through our sensuous organism. From this it follows that the world, apart from our knowledge of it, has neither extension in space nor existence in time; these are properties which we add to it. Cognitions of space and time arise in our intellect during its touch with the external world by means of the organs of sense, and do not exist in the external world apart from our contact with it. Space and time are categories of intellect , i.e., properties which are ascribed by us to the external world. They are signal posts, signs put up by ourselves because we cannot picture the external world without their help. They are graphics by which we represent p. 16 the world to ourselves. Projecting outside of ourselves the causes of our sensations, we are designing those causes in space, and we picture continuous reality to ourselves as a series of moments of time following one another. This is necessary for us because a thing having no definite extension in space, not occupying a certain part of space and not lasting a certain length of time, does not exist for us at all. That is, a thing not in space, divorced from the idea of space, and not included in the category of space, will not differ from some other thing in any particular; it will occupy the very same place, will coincide with it.