consistently with the word's etymology ("perfect" = "finished"). That is perfect which lacks nothing. This is how the term has been used in ontology (a perfect being), ethics (a perfect life) and medicine (perfect health). In these fields, the concept is understood variously as ideal model or as actual approximation to the model. Also called "perfect" is that which completely achieves its purpose. Christian Wolff gave examples from biology (perfect vision) and technology (a clock that runs neither slow nor fast). Here "perfection" is less fictitious model than actual approximation to the model. That is "perfect," which completely fulfills its functions. In social discourse, one speaks of a perfect artist, engineer or carpenter. The term is used similarly in art criticism, when speaking of perfect technique or of the perfect likeness of a portrait. Here again, "perfection" is either ideal model or approximate realization of the model. In aesthetics and art theory, perfection is ascribed to what is fully harmonious — to what is constructed in accordance with a single principle (e.g., the Parthenon, the Odyssey). In business and manufacturing, perfection is one of the principles underlying lean thinking. Except for the first, mathematical sense, all these concepts of "perfection" show a kinship and oscillate between ideal and approximation. However, the expression "perfect" is also used colloquially as a superlative ("perfect idiot," "perfect scoundrel," "perfect storm"). Here perfectum is confused with excellens of an approving, admiring or condemnatory kind. Perfection has also been construed as that which is the best. In theology, when Descartes and Leibniz termed God "perfect," they had in mind something other than model; than that which lacks nothing; than that achieves its purpose; than that fulfills its functions; or than that is harmonious. See also Christian perfection Perfect competition Perfect fifth Perfect flower (bisexual flower) Perfect fourth Perfectionism Perfection (law) Three perfections (Chinese art) Notes References Władysław Tatarkiewicz, O doskonałości (On Perfection), Warsaw, Państwowe Wydawnictwo Naukowe, 1976. An English translation of Tatarkiewicz's book (On Perfection), by Christopher Kasparek, was serialized in Dialectics and Humanism: the Polish Philosophical Quarterly, vol. VI, no. 4 (autumn 1979), pp. 5–10; vol. VII, no. 1 (winter 1980), pp. 77–80; vol. VII, no. 2 (spring 1980), pp. 137–39; vol. VII, no. 3 (summer 1980), pp. 117–24; vol. VII, no. 4 (autumn 1980), pp. 145–53; vol. VIII, no. 1 (winter 1981), pp. 187–92; and vol. VIII, no. 2 (spring 1981), pp. 11–12. Kasparek's