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

- \(p\lor\neg p\) and \(\top\)
- \(p\lor(p\land q)\) and \(p\)
- \((p\lor\neg p)\lor(q\lor\neg q)\) 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.

I’m *Greg Restall*, and this is my personal website. ¶ From August 2021, I will be the Shelby Cullom Davis Professor of Philosophy at the University of St Andrews.

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