So far I've argued that the move from J1 to J2 leads to a contradiction, that it yields a straightforward counterexample, that it falls foul medieval theories of modes of supposition, and that it confuses being a specific man with having a less specific property. I've also explained the origin of the name the identity theory of predication and showed that—based on the text Ms. Lichtenstein cited in support of her claim—Buridan did not believe that “A is B” could be re-interpreted as “A is 'identical' with B”, but was talking about terms suppositing for the “identical” thing. 

Ms. Lichtenstein has flatly ignored the first three arguments, which I left alone because I was pointed to an article about a nominalist's theory. The last, that the very article she cited and—somewhat boastfully—quoted from contradicts the claim that medieval logicians permitted the move from J1 to J2 has also been ignored. What's more, the W. V. article just cited also contradicts the claim that the identity theory of predication is the theory that permits translating “is” to “is identical with” (albeit in slightly different language than the Klima article), and certainly that it permits translating "John is a man" to "John is identical with Manhood".

Do you actually read these articles before you link them, or do you hope that if you post enough of them, mixed with foul, pointless smears, that no one else will? If you're going to post about this again, please do so while addressing the topic of the original post and the arguments given in relation to it.

The only point I wish to make, however, is that John's ideas are controversial (whatever he asserts to the contrary) -- even medieval logicians debated these issues endlessly -- and they are still being thrashed out by logicians --, as the above sources indicate. 

It's not controversial that moderate realists about universals (see the "truism" line) would have found the move from J1 to J2 absurd for the reasons I mentioned, nor that Ockham would have found the claim absurd for the reason I mentioned he would have, nor that Buridan would have. The medievals disagreed over many things (which is why I gave each argument in terms of a specific position), but this isn't one of them.

Poe's whole reason for his original question, I suspect, is that the only way the move from J1 to J2 even makes sense is if you assume that medieval logicians were complete morons, who would have missed an obvious mistake that doesn't, for example, show up in any of their metaphysical arguments.

Last edited by John West (10/21/2015 9:43 am)

A few cautious words: I know of no mainstream Scholastic philosopher who would have accepted the logical and metaphysical conclusions which follow from the account Rosa gives - at best it sounds a like some of the parodies and reductios Abelard presented of his 'extreme realist' opponents.

However one philosopher who may well have found such views congenial is the great John Scotus Eriugena, who developed and an elaborate form of dialectical idealism with strong panentheistic elements. Now it's no secret that Hegel was influenced by Eriugena as well as later panentheists like Bruno - so one can certainly trace a link between Hegel's metaphysics of identity and the (very early) Middle Ages, however it would be wrong to look for it in Scholastic logical treatise.

Last edited by DanielCC (10/21/2015 3:44 pm)

Thank you for those comments. I am going away for a couple of weeks, but will respond when I get back.

Last edited by Rosa Lichtenstein (10/22/2015 8:30 am)

Well, anyone interested in the thread can go to the top, read the comments, and read the links. The articles cited refer to scholastic logicians as upholders of the theory that you claimed is the same as the insane theory you attack in your article. Those scholastic logicians' theories are, however, different from the theory you attack in your article. 

The theory you attack does seem to make sense for the neo-platonist John Scotus Eriugena. Eriugena's influence on Hegel is also, apparently, well documented. So, he's probably your culprit. He was also technically a medieval logician (but not a scholastic).