Wednesday 6 June 2007

A Suggestive Passage in Auriol

In Scriptum I.2.9, Auriol denies that the concept of being is univocal, saying instead that it is wholly ‘confused’ (lacking distinction). He reports the opinion of some others (including, apparently, Scotus):

‘quod conceptus entis includit conceptum substantiae et accidentium disiunctive, et sumus certi de aliquo quod est ens, quia vel substantia vel accidens disiunctive; ignoramus tamen quid sit determinate, sicut audito quod canis est in macello, statim sum certus quod est ibi piscis vel latrabilis canis, non sum autem certus determinate de uno vel de alio. Secundum hoc ergo conceditur quod est alius conceptus entis a conceptibus propriis, sicut disiunctum est aliud a determinato.’ (D.1, §116)

‘that the concept of being includes the concept of substance and of accidents disjunctively, and we are sure of something that it is a being, because <we are sure that it is> either a substance or an accident disjunctively; but we do not know which it is determinately – just as, on hearing that there is a dog in the butcher's, I am immediately sure that there is a dogfish or a barking dog there, but I am not sure determinately about one or about the other. Accordingly, therefore, it is conceded that the concept of being is different from proper concepts in the same way that disjunct is different from determinate.’

Now, this is not Auriol's own opinion. He denies the analogy with the lexical ambiguity in ‘canis’, and he argues that such a disjunct concept could not account for ‹God is a being›. But he does not bat an eyelid at the claim (however taken) that disiunctum is different from determinatum.

Disjunction in Mediaeval Logic

20th-century propositional logic allows ‘or-introduction’: the inference from P to (P v Q) for any Q. This rule is also explicitly stated in Robert Caubraith's Quadrupertitum (1510). But Peter Auriol's Scriptum (1316) denies the inference from ‹Antichrist will be› to ‹Antichrist will be or will not be›. The question is, why?

One answer might be that Auriol takes disjunction to be exclusive, so that (P v Q) is false if P and Q are both true. But although this would invalidate or-introduction as a rule of inference, it would not account for the Antichrist example, in which P and Q cannot both be true.

Another answer might be that Auriol takes ‹P or Q› to have an essential indeterminacy that renders it somehow incompatible with P – perhaps echoing Oswald Hanfling’s complaint in Philosophy and Ordinary Language (2000) that or-introduction falls foul of an ignorance condition: ‘Having been apprised of [P], I am no longer in a position to believe, or to know, that [either P or Q].’

My impression is that Auriol does somehow bind together disjunction and indeterminacy. I intend to investigate this connection.


I've started this blog as an experimental repository for notes on mediaeval philosophy, with no idea how useful, active, or long-lived it will prove to be. I've heard it said that academic blogging is inadvisable, either because people might steal your ideas, or because you might reveal traits that could put off potential employers. But I don't plan to use this blog as a therapeutic outlet, and I like to think of our corner of academia as a collaborative enterprise.