13. With regard to Date:
If "yesterday," "to-morrow," "last year" and similar terms denote parts of time, why should they not be included in the same genus as time? It would seem only reasonable to range under time the past, present and future, which are its species. But time is referred to Quantity; what then is the need for a separate category of Date?
If we are told that past and future- including under past such definite dates as yesterday and last year which must clearly be subordinate to past time- and even the present "now" are not merely time but time- when, we reply, in the first place, that the notion of time- when involves time; that, further, if "yesterday" is time-gone-by, it will be a composite, since time and gone-by are distinct notions: we have two categories instead of the single one required.
But suppose that Date is defined not as time but as that which is in time; if by that which is in time is meant the subject- Socrates in the proposition "Socrates existed last year"- that subject is external to the notion of time, and we have again a duality.
Consider, however, the proposition "Socrates- or some action- exists at this time"; what can be the meaning here other than "in a part of time"? But if, admitted that Date is "a part of time," it be felt that the part requires definition and involves something more than mere time, that we must say the part of time gone by, several notions are massed in the proposition: we have the part which qua part is a relative; and we have "gone-by" which, if it is to have any import at all, must mean the past: but this "past," we have shown, is a species of time.
It may be urged that "the past" is in its nature indefinite, while "yesterday" and "last year" are definite. We reply, first, that we demand some place in our classification for the past: secondly, that "yesterday," as definite past, is necessarily definite time. But definite time implies a certain quantity of time: therefore, if time is quantitative, each of the terms in question must signify a definite quantity.
Again, if by "yesterday" we are expected to understand that this or that event has taken Place at a definite time gone by, we have more notions than ever. Besides, if we must introduce fresh categories because one thing acts in another- as in this case something acts in time- we have more again from its acting upon another in another. This point will be made plain by what follows in our discussion of Place.