Contains 1,001 entries that explore issues of philosophy, psychology, and the physiology of the brain, touching on topics such as sleep, bilingualism, criminology, language, and the workings of the nervous system, and includes biographies of major authorities on the workings of the mind.

This informative and conceptually stimulating target article is very useful. I merely query whether the term “illusory contours” is appropriate for gap filling; “illusory surfaces” seems better – and “fictional surfaces” better still. These seem to be rule based rather than knowledge based, suggesting indeed the importance of distinguishing rules (analogous to syntax in language) from knowledge (equivalent to semantics) for classifying perceptual phenomena.