(1) _Quantity_ has for a universal schema _the series of time_ or number, which represents the successive addition of one and one of the same kind. I can only represent to myself the pure understanding conception of greatness, except as I bring into the imagination a number of units one after another. If I stop this process at its first beginning, the result is unity; if I let it go on farther I have plurality; and if I suffer it to continue without limit, there is totality. Whenever I meet with objects in the phenomenal world, which I can only apprehend successively, I am directed to apply the conception of greatness, which would not be possible without the schema of _the series of time_. (2) _Quality_ has for its schema _the content of time_. If I wish to represent to myself the understanding conception of reality, which belongs to quality, I bring before me in thought a time filled up, or a content of time. That is real which fills a time. If also I would represent to myself the pure understanding conception of negation, I bring into thought a void time. (3) The categories of _relation_ take their schemata from _the order of time_; for if I would represent to myself a determinate relation, I always bring into thought a determinate order of things in time. Substance appears as the persistence of the real in time; causality as regular succession in time; reciprocal action as the regular coetaneousness of the determinations in the one substance, with the determinations in the other. (4) The categories of _modality_ take their schema from _the whole of time_, _i. e._ from whether, and how, an object belongs to time. The schema of possibility is the general harmony of a representation with the conditions of time; the schema of actuality is the existence of an object in a determined time; that of necessity is the existence of an object for all time.