Men of science are sometimes mistrustful of or at least impatient with philosophy. One of them, himself no stranger to hard thought, was one day heard to comment on his colleagues in another faculty and on their propensity to indulge in what he called "all this nonsense about thinking". Against this may perhaps be set a meeting of philosophers who decided to discuss the Second Law of Thermodynamics. When asked sardonically by a scientist whether they had disproved it, one of the philosophers replied: "No, we have concluded that it is not so much false as meaning­ less" . This curious appearance of cross purposes reflects something more than mere captiousness or misunderstanding. As to the "nonsense about thinking", it is perfectly true that an excessive formalisation of argu­ ments does not usually assist clear thinking very much. Plenty of people would be nonplussed by a formal logical exercise of the type: all A is B, Cis B: is C therefore A? But equate A to Frenchman, C to Germans and B to Europeans, and tht:y would never run the slightest risk of going astray.