"I am conscious [said Kant] of my identical self in relation to all the variety of representations given to me in intuition, because I call all of them _my_ representations.... The thought, 'These representations, given in intuition, belong all of them to me,' is just the same as 'I unite them in one self-conscious.'... Synthetical unity of the manifold in intuition, as given _a priori_, is therefore the foundation of the identity of apperception itself, which antecedes _a priori_ all determinate thought. But the conjunction of representations into a conception is not to be found in objects themselves ... but is on the contrary, an operation of the understanding itself, which is nothing more than the faculty of conjoining _a priori_, and of bringing the variety of given representations under the unity of apperception. This principle is the highest in all human cognition." So, to the _existence_ of any _distinguishable object_, there must _pre-exist_ the element of mind in the phase of _self_-consciousness as well as _sub_-consciousness. Both must enter the object. Hence, when Kant talked of "_the objective unity of self-consciousness_"--another of his profoundest deductions--he meant literally that "the synthetical unity of apperception," as well as "the synthetical unity of apprehension," is _materialized_ in all _conceivable things_. To form the sense-effects of a stone into a single "intuition," they must be merged in a synthesis of apprehension; but to _set_ the intuition as thus created--to make it remain _itself_ in the midst of _others_, it must be merged with them in a higher synthesis--a common connective consciousness, which, distinguishing them in itself, re-presents them as distinguished. It was here that Kant reached his famous "_Categories_," which are merely reflexes of the pure synthetical unity of mind, as forming the unity of all things and of all connection among them. The principle of mind, beginning, as we have seen, even with the instinctive mind of sense, is a spontaneous self-activity, receptive, reflexive, and resumptive of its doubles. By being the first, it unifies any and every manifold of sense-effects; by being the second, it _re_-presents the product--throws it _out_; by being the third, it apprehends the externalisation, and a percept is born. Apperception, or full consciousness, is the same self-activity, self-reflex, self-sight, transformed into "understanding." Thus, mind is essentially a _triad_ as well as a _unit_. But, if so, it must reflect itself to conception as a "_Quantity_"--a sum of its own phases; and in these phases, it is a "Unity," a "_Plurality_," and a "_Totality_."