(1) No y is identical with Caesarto which David Brightly objected that
(2) Some x was identical with Caesar
(3) Some x is not identical with any y
For (1) to be true it's clear that the range of the quantified expression 'no y' cannot be all men who ever were. Rather the present tense 'is' modifies the quantifier 'no man' restricting the ys in (1) to the presently existing men. Similarly in (2) the past tensed 'was' modifies the quantifier 'some x', restricting the xs to the men who ever were, ie, no restriction at all.Well that’s true, and that’s one solution proposed by some of the scholastics, who thought that the present tense of the main verb of the sentence restricts (Latin: restringit) a common term like ‘man’ to suppositing (i.e. ranging over) presently existing men (praesentibus).
What’s wrong with that solution is the present tense that we have to use when we say what things are in the domain or range of quantification. David says that using a verb in the past tense allows the quantifier it to range over all the man that ever were. The problem is the implied present tense of the ‘ranging’. How is it that the quantifier ‘ranges’ – present tense – over past men, men who longer exist? Surely it can’t. Nor can the domain now ‘contain’ all such men. It used to contain them, but now it doesn’t. So the second premiss (2) cannot be true. There cannot be any x that was identical with Caesar, because however wide the domain or range of quantification, the domain exists in the present. It has to exist in the present because we say that it is the range of our quantification, and to say that we must use the present tense.
Anthony is closer when he says that the real problem is presentism, but there are problems with presentism also, which I will talk about later.