¹ I think it should be added that instinctive impulse, as well as affective or emotional thought, are attributes of man deriving from the central part of the brain, that is inherited from our remote ancestors: the paleoencephalon. An entire issue of the Courrier of UNESCO was recently (January, 1976) devoted to studies on this subject. Completing the thought of a psychologist, we could add: We know we will die (left hemisphere); we do not believe it (paleo encephalon); and we cannot imagine it (right hemisphere). A ternary classification of thought would be the consequence of these experimental studies, justifying the hypothesis of a ternary division in ideas that I proposed in my work l'Homme microscopique (Flammarion, Ed., 1966); in an article in Diogenes (No. 22, Summer, 1958); and in an article in the journal Leonardo (Maxwell, Ed.).

² What students of prehistory, in the absence of symbolic cultural signs, call culture: paleolithic culture, neolithic culture, etc.

³ Here we do not pretend to judge the internal coherence of mathematical theories, a question best left to specialists in the field.

⁴ We recall the descriptive comment of Samuel Butler in his Notebooks mentioning the frightful occurrence of a superb theory, excellent in all respects, savagely assassinated by an ugly little fact.

⁵ Moreover, there is indirect confrontation through the intermediation of a developed organism.