What is "illusionism"

n. 1 The performance of magical tricks. 2 The theory of dealing with illusions. 3 The doctrine that the material world is an illusion. 4 The use of illusionary effects in sculpture and art.

Illusionism in art history means either the artistic tradition in which artists create a work of art that appears to share the physical space with the viewer or more broadly the attempt to represent physical appearances precisely – also called mimesis. The term realist may be used in this sense, but that also has rather different meanings in art, as it is also used to cover the choice of ordinary everyday subject-matter, and avoiding idealizing subjects. Illusionism encompasses a long history, from the deceptions of Zeuxis and Parrhasius to the works of muralist Richard Haas in the twentieth century, that includes trompe-l'oeil, anamorphosis, Op art, Abstract Illusionism, and Illusionistic ceiling painting techniques such as di sotto in sù and quadratura. Sculptural illusionism includes works, often painted, that appear real from a distance. Other forms, such as the illusionistic tradition in the theatre, and Samuel van Hoogstraten's "peepshow"-boxes from the seventeenth-century, combine illusionistic techniques and media.

Illusionism is a metaphysical theory first propounded by professor Saul Smilansky of the University of Haifa. It holds that people have illusory beliefs about free will. Furthermore, it holds that it is both of key importance and morally right that people not be disabused of these beliefs, because the illusion has benefits both to individuals and to society. Giving up a belief in hard incompatibilism, argues Smilansky, removes an individual's basis for a sense of self-worth in his or her own achievements. It is "extremely damaging to our view of ourselves, to our sense of achievement, worth, and self-respect".

Neither compatibilism nor hard determinism are the whole story, according to Smilansky, and there exists an ultimate perspective in which some parts of compatibilism are valid and some parts of hard determinism are valid. However, Smilansky asserts, the nature of what he terms the fundamental dualism between hard determinism and compatibilism is a morally undesirable one, in that both beliefs, in their absolute forms, have adverse consequences. The distinctions between choice and luck made by compatibilism are important, but wholly undermined by hard determinism. But, conversely, hard determinism undermines the morally important notions of justice and respect, leaving them nothing more than "shallow" notions.

Smilansky's thesis is considered a radical one, and other philosophers disagree with it. Professor Derk Pereboom of Cornell University, for example, disagrees that hard incompatibilism necessarily does away with self-worth, because to a large extent that sense of self-worth isn't related to will at all, let alone to free will. Aspects of worthiness such as natural beauty, native physical ability, and intelligence are not voluntary. Professor James Lenman of the University of Glasgow (at the time) takes a similar line, arguing that Smilansky's expression of the problems is overstated. The problems that he presents are less fundamentally metaphysical than simply practical in nature.