…ful method in logic, when you’re trying to figure out if two models are elementarily (logically) equivalent or not. This may be of special interest to philosophers of science, since the ’empirical equivalence’ of two models is much better characterized by elementary equivalence than it is by isomorphism. At any rate, I’ve written a friendly introduction to this method (PDF). Here’s a little of what you’ll find there. Ehrenfeucht-Fraisse games invo…
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…your business model runs completely counter to the aims of the academic community, for this reason: academic publishing is not like commercial publishing. Stop conflating the two. I know of nary an academic that is publishing for the bling. So, stop thinking of us as obscure niche counterparts to J. K. Rowling. Scholarly authors would be crazy to write books for the tiny (or often non-existent) monetary compensation. They do it to disseminate inf…
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…nd the Cosmos where Ashtekar is director. Our discussion was about the arguments underpinning the evidence for time asymmetry in fundamental physics. Our discussion has finally come out in a special issue of Studies in History and Philosophy of Modern Physics: Roberts (2014) Three merry roads to T-violation (philsci-archive) Ashtekar (2014) Response to Bryan Roberts: A new perspective on T violation (arxiv) Roberts (2014) Comment on Ashtekar: Gene…
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…posts! The following posts received either a lot of traffic or a lot of comments (or both) in 2009. Where the material conditional gets its truth conditions. A simple explanation to aid students of classical predicate logic. Hyper-intelligent fish and black hole thermodynamics. A thought on the well-known analogy between hydrodynamics and black hole thermodynamics. Can Time Unfold in the Wrong Direction? An argument that yes, it can, according to…
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…I call this the ‘Jesuit law’ of free fall. There was no agreed upon experimental evidence in the 1640’s that could verify one law and falsify the other. (Each side claimed to have experiments that vindicated their law, and disproved their competitor’s law.) However, a clever theoretician might still try to use purely theoretical means to prove one side false. The Challenge. Prove that the Jesuit law is false, without assuming Galileo’s law. Some…
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