{{Merge|Accident_(philosophy)|date=July 2007}}

[[Aristotle]] made a distinction between the ''[[essential properties|essential]]'' and ''accidental'' [[properties]] of a thing. An '''accidental property''' is one which has no necessary connection to the [[essence]] of the thing being described.<ref>Metaphysics: Books Zeta and Eta http://www.sparknotes.com/philosophy/aristotle/section6.rhtml</ref><ref>Aristotle on Non-Contradiction, and the role of Aristotelian Essentialism http://plato.stanford.edu/entries/aristotle-noncontradiction/</ref>

A trivial example may help to illustrate the distinction. It is an ''essential property'' of bachelors that they are unmarried, but it is an ''accidental property'' of bachelors that they have brown hair. This is because it is logically impossible to find a married bachelor anywhere in this or any other possible world, and therefore the property of being unmarried is a necessary or essential part of being a bachelor. On the other hand, brown hair is a ''contingent'' or accidental property of bachelors since some bachelors have brown hair and others do not. Even if for some reason all the unmarried men with non-brown hair were killed, and every single existent bachelor had brown hair, the property of having brown hair would still be accidental, since it is the case that in some possible world, a bachelor could have hair of another color.

Aristotle addressed 10 different categories in his ontology, which could include categorization of different types of accidental properties.<ref>Predication and Ontology: The Categories http://faculty.washington.edu/smcohen/433/catlec.htm</ref>

== Notes ==
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[[Category:Classical Greek philosophy]]
[[Category:Aristotle]]