It was often claimed that the justification for teaching Latin as a subject was that it trained the mind and developed thinking skill. It could be argued that if content subjects failed to teach thinking because the important of the content obscured the thinking process, then a subject in which the content was irrelevant would teach thinking because attention could be focused only on the process. But although the subject might be irrelevant, it was the complex rules of the subject that determined the correctness of an answer, not the amount of thinking involved. Once again knowledge was more important than thinking.

The problem of transfer is always present. As a demonstration of deductive thinking Euclidean geometry is superb. A few axioms are built into theorems. The theorems are then applied to solve problems. I doubt if there has ever been a philosopher or a teacher who has not wished for a thinking system as controlled and as perfect. But, alas, excellence at geometry is of little help in solving problems outside architecture and engineering.