>>>"Luis: 'Putnam presents what he considers to be invalid arguments by Quine' Harv: 'Many exceptions. For example, Putnam is clear that he is presenting Quine's argument.' "
Putnam: "Quine defined a 'tautology' (i.e., a logical truth in propositional calculus) to be an instance of a schema all of whose substitution instances are true. (As an example, think of the schema 'p . p.q'). But this Quinian definition is unsatisfactory for several reasons..."
Putnam: "Moreover, Quine’s definition of truth-functional validity as “truth of all substitution instances” – that is, truth-in-L of all substitution instances – is not extensionally correct in all cases."
>>>"I didn't see any clear argument against ontological commitments per se."
Putnam: "Quine rejected (equivalent optional languages), not as an impossible formalization of mathematics, but as one makes ontological commitments unclear. In other words, unless you formalize mathematics in precisely the kind of logic to which his criterion of ontological commitment applies, then, you are somehow cheating! The very idea that the modalities have (or may have) hidden 'ontological commitments' shows just how deep the Platonist bug had bitten Quine by this time..."
You need a little (perhaps a lot) more time to digest Putnam. You might even more time to review our own posts:
>>>"Luis, it was you who said 'just doing our best to prevent cognitive phenomena from becoming fixed mental paradigms'."
Harv: "Just doing our best to prevent cognitive phenomena from becoming fixed mental paradigms is impossible since everything we know we are committed to. For example, are you committed to biological evolution having occurred? .>>" ( http://www.astronomy.net/forums/god/messages/21184.shtml )
Try again. With a little more time to read Putnam, you'll see that in the following excerpt, you are making my point for me:
"***Is this ‘truth’ something you, a human, have inferred?***
***If so, and it is an inference, how can you claim it as something you "know"?***
My claims are based on an internalist explanation as a means to reconcile my internal experience to what I believe must be happening externally. This inference is so strong that I just believe these ontological commitments are a correct ontology.
*** If not, and it is a fact, then how did you manage to escape that human limitation you posited thus: "True objectivity by a human is not possible"?***
I didn't escape it, I just came to realize the importance of faith."
In other words, "Ontology" is faith. Your mind is fooling itself, because it needs the vehicle Putnam describes in his fourth lecture. Ontology is way you escape from the overwhelming feeling that I cannot really know anything. And though I refrain from telling myself "I know this," I am overwhelmingly confident there is no underlying "Ontology" behind everyone's assertions.