 Cook Wilson did not contribute to logic. His inclination was at any rate conservative. For example, there was for him no room even to try and make a case for an alternative logic, since he held the Aristotelian principles (the principle of syllogism, the law of excluded middle and the principle of contradiction) to be “those simple laws or forms of thoughts to which thought must conform to be thought at all. Thought therefore cannot throw any doubt on them without committing suicide” (ETA, 17 &amp; SI, 626). Cook Wilson also rejected new developments in symbolic logic from Boole to Russell. He was not as such adverse to the “symbolization of forms of statements”: when criticizing Boole’s he alluded to “an improved calculus of [his] own” (SI, 638), which he called “fractional method” (SI, 662). But he did not publish it and all we have is the beginnings of an outline (SI, 192–210). His main objection to Boole—a common one at the time—was to the algebraist’s use of equations, perceived as an intrusion of mathematics in logic (SI, 635–636). (See the whole chapter (SI, 635–662).) And the little he knew of mathematical logic, Cook Wilson ferociously opposed. He did think of syllogistic as “a science in the same sense as pure mathematics” (SI, 437), but he was opposed to the very idea of logical foundations for mathematics because he believed that logical inferences are exhausted by syllogistic and, “mathematical inference as such is not syllogistic” (SI, xcvi). This is a misunderstanding, common at the time, of the expressive power of quantification theory as developed among others by Gottlob Frege and C. S. Peirce, of which he was clearly insufficiently cognizant, if not plainly ignorant.