doubtful whether the techniques used can be abstracted to general cognition. Another mathematical program, called Geometry, was celebrated for making an insightful discovery of an original proof that an isosceles triangle has equal base angles. The proof is based on seeing the triangle in two different ways. However, the program generates all possible ways of seeing the triangle, not even knowing that it is the same triangle. Hofstadter concludes with some methodological remarks on the Turing Test. In his opinion it is still a good definition and he argues that by interacting with a program, a human may be able to have insight not just on its behaviour but also on its structure. However, he criticises the use that is made of it at present: it encourages the development of fancy natural-language interfaces instead of the investigation of deep cognitive faculties. Editions References 1995 non-fiction books Cognitive science literature Books by Douglas Hofstadter Analogy Books about metaphors