Introduction to Fuzziology
Vlad Dimitrov · Studies in fuzziness and soft computing · 2002
In a broad sense, fuzziness is the opposite of precision. Everything that cannot be defined precisely (that is, according to some broadly accepted criteria or norms of precision) and everything that has no clearly described boundaries in space or time is considered a bearer of fuzziness. In a narrow sense, fuzziness relates to the definition of fuzzy sets [1] as proposed by Zadeh in 1965: sets, the belongingness to which is measured by a membership function whose values are between 1 (full belongingness) and 0 (non-belongingness).