It is the phenomenon of an expression to expand (not restrict) the class of objects for which a term supposits or refers. E.g. in 'Some man is white', the expression 'man' supposits for presently existing men. However, in 'Some man was white', the same expression now supposits for previously and presently existing men because of the tensed verb 'was'. Likewise, modal verbs cause ampliation to possible objects.
One might think ampliation is required to get the right truth conditions for tensed statements. E.g., if "Some man (who no longer exists) was white" is true just in case there was a man who was white, and that that's true just in case there is (tenselessly) a man who was white (e.g. Socrates), then the domain needs to include past men (assuming that man no longer exists).
Roughly, it corresponds respectively to the de dicto/de re distinction. I say "roughly" because in the composite sense, necessity is taken as a sentential predicate rather than a propositional operator. For example, there are two senses of 'The number of planets is necessarily eight', namely:
Priest and Read claim that for Ockham, while there is a tensed analog of the divisive (de re) modal form, there is no analog of the composite form. This holds even for a modal and tensed sentence of the same form in natural language (as with 'Some white thing can be black' and 'Some white thing was black'). In other words, "the predicate of a tensed sentence has unambiguous supposition", in the sense that it always supposits for what was in a past-tensed sentence. This strikes me as strange for a presentist like Ockham. However, PR will go on to claim that it has its advantages.
First, the standard account gives 'Some A is possibly B' the logical form 'Something is such that it is possibly A and possibly B'. But this looks wrong. An assertion of 'Some politician could have been a lawyer' does not mean that there is something that could have been a politician and could have been a lawyer, for we all satisfy that. It means, rather, that there is a politician and that person could have been a lawyer.
Second, the ampliative account, according to which tensed sentences are given disjunctive truth conditions, makes it too easy for tensed sentences to be true. E.g. 'Some man was white' means that some present or past man was white, and that can be true even if no presently existing man was white. But clearly relative to some (possible) contexts, an utterance of 'Some man was white' means that some presently existing man was white, and hence can be false if no presently existing man was white.
This is a peculiar claim to make. It's not actually clear what the ampliative account yields here since 'Napolean' is a singular term, not a general one like 'man', but let us suppose that it means the same as 'Some "Napoleanizer" was never in France'. (In the Klima reading for this week, he notes that Buridan remarks that you cannot speak about ampliation for singular terms.) The disjunctive account yields that the sentence is true iff some present or past Napoleanizer was never in France. Since one's cat does not qualifier as a Napoleanizer (being an abbreviation and that unique picks out Napolean, the person), it is not true just because there is a cat called 'Napolean' who has never been to France. What they say would be true if the sentence were 'Someone called 'Napolean' was never in France', but that is quite different from 'Napolean was never in France'.
Milleans about proper names hold that the meaning of a singular term is nothing over and above the thing it names. This provides a simple account of the meaning of singular terms but faces a good number of difficulties. For instance, this naive Millean account assigns the same meaning to 'Santa Claus' and 'Pegasus', assuming that these names fail to refer (which oen might reject).
If dinosaurs don't presently exist but 'dinosaurs' can supposit for them, it seems that they must exist in some sense, i.e. eternalism, the doctrine that past, present and future things exist, is true (given a parallel treatment of the future tense).
This is topic of debate and many think that we cannot. We can see, however, that Klima is thinking of singular terms like 'Wyman' as disguised descriptions ('The thing that is Wymanizing') which may explain why he thinks we can. But even in the case of artificial descriptions like this, how are we to guarantee that, in any world where the discription is satisfied, it is uniquely satisfied? It seems we can only through an identity with some singular thing which we would have to be able to name in the first place, so that a definition of 'The thing that is Wymanizing' would look like 'The unique x such that x is a person and....and x is identical to Wyman'. And how could we do that without Wyman actually existing?
Buridan makes it clear that we cannot be thinking of nonbeing, since nonbeing is nothing and therefore cannot be understood. What he does not make clear, however, is how it is we can think of or understand something that does not exist, but may have or could exist. In the case of someone who did exist, we could appeal to the concept of the person which exists mind-dependently and independently of the person. We can think of Quine in virtue of having a concept of Quine under which Quine once fell.
Not very! He is still committed to the claim that we can refer to and signify things that don't exist, which is thoroughly Meinongian view!