Handbook of the History of Logic: - Fordham University Faculty

204 Terence Parsons
proposition (for it to be true). Likewise, one must be discussing possible
pink donkeys in the second; otherwise the proposition would be false. This
ampliation is caused by the modal words ‘can’ and ‘necessarily’.
4. Supposition for impossible but conceivable things, caused by words that
“pertain to the soul”:
A chimera is believed to be an animal.
A bishop wants a donkey which is a stone. 55
Authors disagree about the truth values of these cases, but they seem to agree
with the semantic mechanism. Certain verbs such as ‘believe’ or‘want’ are naturally
used with terms that appear to supposit for things that are not possible.
Since it is impossible for a chimera to exist, one must take the first proposition
to contain supposition for not just actual or possible chimeras, but for impossible
ones (if there are any) too. Some authors reject this ampliation because they hold
that there are no impossible things, and so terms cannot supposit for them. For
simplicity, I will interpret these latter authors as agreeing with the semantic principle
that in such contexts the correct semantics is to let the terms supposit for
absolutely all things that they signify, 56 and this will include impossible things if
there are any. The sentences will then be taken to have different truth values for
those who disagree about whether there are any impossible things. For example,
Buridan does not accept impossible beings; so he would consider the first proposition
above to be false; since chimeras are impossible, there aren’t any chimeras
to have beliefs about. The subject term is ampliated to supposit for impossible
things, but since there aren’t any impossible things, the subject is empty and the
sentence is false.
The following subsections will discuss temporal ampliation by tenses, ampliation
to the merely possible by (alethic) modal words, and ampliation to all things
whatsoever by verbs which indicate an act of the soul. These all have a semantic
account that is uniform across tenses and modals. It has two parts.
One part is how elements of a proposition affect what terms supposit
for: A present tense (on an ordinary verb) restricts the terms to suppositing
for the presently existing things that they presently signify; a
past tense on an ordinary verb ampliates the subject term to supposit
for both presently and formerly existing things that it signifies or signified,
and ampliates the predicate term to supposit for the things that
it will signify; and similarly for the future tense, and for modal words,
and for verbs pertaining to the soul.
55 Note that the subject term is not ampliated in this example, since it occurs with a present
tense non-modal verb. The verb pertains to an act of the soul, and this affects the supposition
of terms that come after it, but the subject of such a verb is not thereby ampliated.
56 Not just verbs that pertain to the soul do this; semantic words such as ‘signify’ and‘supposit’
ampliate terms following them so that they supposit for everything that they signify. See section
5.5.