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.