In a comment Bill V explains about 'untensed' verbs:
Only an anti-presentist would claim this because he sees 'exists' as tenseless here. The presentist sees 'does exist' as tensed and regards the assertion as clearly false. Caesar does not exist yet Caesar was a Roman. What the anti-presentist asserts is
If x does not exist*, then no predicate is true of x.That is
If not (x exists*), then no predicate is true of x.which expands to
If not (x exists or x existed), then no predicate is true of x.Or, in other words,
If x doesn't exist and didn't exist, then no predicate is true of x.And who would disagree with that?
So (metaphilosophical message coming) the dispute is not about the nature of reality at all. We all agree on that. It lies in the language used to express it.
Next up: Relations between non-existent (but not non-existent*) objects.
And more explanation appears further down the thread.
Now I have trouble with this. I grant that talk of abstractions, especially mathematics, use the present tense forms of 'to be' and 'to exist', viz, 'is' and 'exists', and this could be said to be a 'tenseless' usage. There is no call for tense in the unchanging world of numbers and patterns. But Bill wants to talk about the changing concrete world in an untensed way. Well, OK, but be on the lookout for pitfalls.
Let me use 'is* 'and 'exists*' to denote untensed usages of 'is' and 'exists'. My claim is that 'is*' and 'exists*' may look like verbs, and to an extent function as verbs, but they are not verbs. They are in fact shorthand, replacement schemes, or for computer geeks, macros. When Bill asserts
what he appears to mean is
Roughly, any sentence of the form '...is*...' is to be expanded to the disjunction '...is... or ...was...' We can now see why 'is*' has no past tense form---it's already in there! Only roughly, because there is a nasty interaction with negation we need to take care of.
Let's rewrite Bill's example. We need to take care with the negations. He says
Peforming the macro expansions of the 'exist*' and 'is*' we get
And expanding the parentheses we get
Indeed it does not follow.
The notion of quasi-verbs as macros goes a long way to explain the presentism/anti-presentism controversy. Those of the presentist persuasion, such as myself, eschew these so-called 'tenseless' constructions, whereas anti-presentists cling to them. Here's an example from Bill's latest.