## What Proofs and Truthmakers are About

#### August 12, 2016

I was originally scheduled to give a talk entitled “What Proofs are About” at the About Aboutness Workshop at the University of Melbourne on Saturday, July 16, 2016, but my plane back to Melbourne was delayed and I didn’t get to present the paper then.

So, I’m presenting it at the Melbourne Logic Seminar instead.

Abstract: This talk is a comparison of how three different approaches to subject matter treat some pairs of statements that say different things but are (classically) logically equivalent. The pairs are

1. $$p\lor\neg p$$ and $$\top$$
2. $$p\lor(p\land q)$$ and $$p$$
3. $$(p\lor\neg p)\lor(q\lor\neg q)$$ and $$(p\lor\neg p)\land(q\lor\neg q)$$.

I compare and contrast the notion of subject matter introduced in Stephen Yablo’s Aboutness (Princeton University Press, 2014), truthmakers conceived of as situations, as discussed in my “Truthmakers, Entailment and Necessity,” and the proof invariants I have explored in recent work.