1274) explains why Avicenna explores it the way he does...

1274.explains why Avicenna explores it the way he does: What spurred him to this was that in the assertoric syllogistic Aristotle and others sometimes used contradictories of absolute propositions on the assumption that they are absolute; and that was why so many decided that absolutes did contradict absolutes. When Avicenna had shown this to be wrong, he wanted to give a way of construing those examples from Aristotle (Tusi (1971) Sharh al-Isharat 312.5-7).

Revisionist Avicennan Logicians By and large, the Revisionists adopt most of Avicenna's distinctions and stipulations. But - on their preferred reading of the proposition - they reject, among other inferences. If every J is possibly B, and every B is necessarily A, it doesn't follow that every J actually becomes B such that it is necessarily A.

Kâtibî does not ampliate the subject term to the possible (so that it would be understood as every possible B is necessarily A), nor does he read each proposition as being embedded in a necessity operator. Rather, he understands the possibility proposition as follows: there are Js, and whatever is at one time J is possibly B. This means that Kâtibî and the other Revisionists have a modal syllogistic that differs significantly from Avicenna's.

The way the Revisionists put this difference is as follows: Our statement every J is B is used occasionally according to the essence ( hasab al-haqîqa ), and its meaning is that everything which, were it to exist, would be a J among possible individuals would be, in so far as it were to exist, a B; that is, everything that is an implicand of J is an implicand of B.

And occasionally [it is used] according to actual existence ( hasab al-khârij ), and its meaning is that every J actually ( fî l-khârij ), whether at the time of the judgment or before it or after it, is B actually ( fî l-khârij ). The distinction between the two considerations is clear.

Were there no squares actually ( fî l-khârij ) it would be true to say a square is a figure under the first consideration and not the second; and were there no figures actually other than squares, it would be correct to say every figure is a square under the second consideration but not the first (Kâtibî (1948) Shamsiyya 91.1-4, 96.12-14).

In fact, the Revisionists are prepared to accept the Avicennan inferences given an essentialist reading of the propositions, but this is a half-hearted concession never pursued in their treatises.

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