Abstract
The use of introspection is unavoidable even in psychological research on animals. Difficulties may arise from the absence of reliable introspective data; it is suggested that this could be the case for the so-called “reward system”. In other circumstances confusion comes from using introspection without being aware of it: speaking and thinking have for many years been considered as the same operation, but the reason for this belief is not clearly documented and it may be suspected of being only introspection. Amongst other evidence, a careful and conscious use of introspection demonstrated by auto-analyses of former aphasic patients strongly suggests that language and thought are quite distinct entities.