  The “traditional logic” that Strawson discusses is much closer to that of nineteenth century logic texts than it is to the version that held sway for two millennia before  that.[28]  But even though he literally salvages a version of nineteenth century logic, the view he saves is unable to serve the purposes for which logical principles are formulated, as was pointed out by Timothy Smiley in a short note in Mind in  1967.[29]  People have always taken the square to embody principles by which one can reason, and by which one can construct extended chains of reasoning. But if you string together Strawson’s entailments you can infer falsehoods from truths, something that nobody in any tradition would consider legitimate. For example, begin with this truth (the subject term is non-empty):