That every noumenon is a mental sign is a matter of course; the noumenal world is ideal. But we maintain that these mental signs represent real qualities of the objective world; they have a meaning; the things represented by them are actual features of reality. Kant denies this. To him the noumenal world is purely noumenal. To Kant there is no space outside the space-conception, and so he declares that space is ideal; it is not an objective quality of things. However, we maintain, that our space-conception describes, i. e. depicts, or represents space, our space-conception is ideal, yet space is not ideal but real; it is an objective quality of the world. Kant’s view is dualistic, or at least necessarily leads to dualism, and it appears to rest on an unpronounced dualistic assumption. Kant treats “the subject” as something quite distinct and separate from “the object.” If he had borne in mind that the subject is always at the same time an object, he would have treated both subject as well as object as mere abstractions of one and the same reality. Resting upon this erroneous presupposition, Kant’s most consequential mistake, in our opinion, was his conception of what he called “the ideality of time and space.” If time and space were purely ideal, purely mental, purely subjective, then indeed, the things as they are would forever remain unknown to us, then indeed the thinking mind would be as if shut up within a hollow globe out of which it could never escape, then indeed the world would be divided into two parts, the objective world, and the subjective world; and the gap between both could never be bridged over. The thinking mind would have within itself a noumenal world built upon the subjective elements of sense-impressions. This subjective world would possess no objective value, it would not describe realities, and the objective world would thus be unknowable, inscrutable, and mystical. The idea of a thing in itself found another support in a mistaken conception of the unity of certain things, especially of organisms. The unity of a combination of parts is not merely the sum of the parts, it consists in their peculiar combination which makes an harmonious co-operation possible. This unity is an additional element; it is an entirely new creation which exhibits features not contained in any of its parts. There is no latent watch contained in a heap of little wheels and cogs, the watch is created through the combination of these wheels and cogs. The unity of a thing is its form, consisting in a special arrangement of its parts; and this form although not material is nevertheless real. The materialistic conception overlooks the importance of form; but the spiritualist and also the transcendentalist materialise it as some spiritual substance, as entities or independent existences. They are in this way as much materialistic as the materialist.