If in the disclosures which Kant's wonderful acumen gave to the world there is anything true beyond the shadow of a doubt, this is to be found in the Transcendental Aesthetics, that is to say, in his doctrine of the ideality of Space and Time. On such solid foundations is the structure built that no one has been able to raise even an apparent objection. It is Kant's triumph, and belongs to the very small number of metaphysical theories which may be regarded as really proved, and as actual conquests in that field of research. It teaches us that Space and Time are the forms of our own faculty of intuition, to which they consequently belong, and not to the objects thereby perceived; and further, that they can in no way be a condition of things in themselves, but rather attach only to their mode of =appearing=, such as is alone possible for us who have a consciousness of the external world determined by strictly physiological limits. Now, if to the Thing in itself, that is, to the Reality underlying the kosmos, as we perceive it, Time and Space are foreign; so also must multiplicity be. Consequently that which is objectivated in the countless phaenomena of this world of the senses cannot but be a unity, a single indivisible entity, manifested in each and all of them. And conversely, the web of plurality, woven in the loom of Time and Space, is not the Thing in itself, but only its =appearance-form=. Externally to the thinking subject, this appearance-form, as such, has no existence; it is merely an attribute of our consciousness, bounded, as the latter is, by manifold conditions, indeed, depending on an organic function.