Friday, December 16, 2011

Ockham's Fregean moment

I am working on chapter 67 of Ockham's master work, where I find something that reminds me of Frege.  Ockham is talking about 'material supposition'.  This is a mode of supposition where a word stands for itself.  It's rather like when a word is enclosed in quotation marks (which the medievals didn't have), except the whole point of quotation marks is that we create a new word to stand for the unquoted word, and so the word precisely doesn't stand for itself.

Ockham claims that there are situations when a word signifies something that it does not materially supposit for. His example is the sentence "animal is predicated of man", in Latin: animal praedicatur de homine.  Note the word 'homine', which is the ablative case of the word 'homo'.  This is important, for Ockham's sentence is true because 'a man is an animal' is true, which in Latin is homo est animal.  Note the nominative case of 'homo'.  So when we say "animal is predicated of man", we mean that animal is predicated of homo, not homine.  But we can only say that using the word homine, at least in Latin.  (Or perhaps the same is really true in English, except the ablative of the word 'man' is the same as the nominative?)  Thus the quoted homine signifies itself, i.e. homine, but supposits for its nominative homo. (Hope that makes sense).

That seems trivial.  But it seems remarkably close to Frege's famous puzzle about the concept horse.  Frege held that simple propositions like 'Red Rum is a horse' are composed of Object and Concept.  The object is signified by the object word "Red Rum" and is thus Red Rum himself.  The concept is signified by the predicate " - is a horse".  Let's call that the concept Horse.  But now the puzzle.  The sentence "the concept Horse is a concept" is also a simple sentence, where the term "the concept Horse" occurs in subject position.  So it signifies an Object, according to Frege.  And so is not a Concept.   Thus, the concept Horse is not a concept.  Frege admits this is odd.
It must indeed be recognised that here we are confronted by an awkwardness of language, which I admit cannot be avoided, if we say that the concept horse is not a concept, whereas, e.g., the city of Berlin is a city, and the volcano Vesuvius is a volcano.
This seems remarkably similar to Ockham's puzzle about homine, although it would take some work to tease out the underlying basis of it, if any.

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Blogger J said...

Again you're overlooking the point that term logic doesn't deal with individuals. So like your first variable! (and Frege's system odd anyway)

10:29 pm  

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