Thursday, October 05, 2006

The Formality of Logic

As announced on the Leiter blog, Josh Dever has created a page with links to PhD dissertations. It includes a very interesting dissertation by John G. MacFarlane which is entitled "What does it mean to say that logic is formal?". Particularly interesting is Chapter 4 on 'Kant and the formality of logic'. He argues that Kant invented formal logic and did so because of his transcendental idealism. "Not only did Kant invent logical hylomorphism, but he invented it because his transcendental idealism required it!" (p. 126)

I also like what he says about his historical approach. In justifying this approach to the study of logic MacFarlane modifies the well-known Kantian slogan so that it says: "intellectual history without conceptual analysis may be empty, but analysis without history is blind." (p. 26)


Blogger Andreas said...

MacFarlane writes, "Kant seems to have been the first modern philosopher to demarcate logic (or a significant portion thereof) by its formality." (79) MacFarlane uses his taxonomy of formality, introduced in the previous chapter, to argue that "the sense of formality at issue here is 3-formality: abstraction from all semantic content of the representations used in thought." (87f).

So, the point is that Kant was the first modern philosopher to emphasize that logic "delivers no knowledge of fact — not even of the most abstract and general facts (facts about identity or existence, for example)." (88).

The interesting question, I think, is how this is connected to another important aspect of what people ordinarily mean in saying that logic is formal, namely that logic is topic-neutral, i.e. that logical consequence (or validity) is supposed to be insensitive to content. Probably, one will get an answer to what MacFarlane thinks of this by close-reading the sections introducing the distinction between the three notions of formality.

Actually, in my present state of information, I believe that Aristotle already knew that logic was topic-neutral. But he probably did not think that logic does not deliver any knowledge of facts.

2:30 pm  

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