Fuzzy logic, unlike classic or Boolean logic, suggests that in reality things cannot be presented in simple binary terms but rather as a set of degrees of truth similar to probabilities.
Idealism states that everything real is created by the human mind. The entities observed make sense only when conceptualised. Experience and consciousness are the basis of validity.
Phenomenology is a philosophical viewpoint that opposes objectivism but emphasises the importance of cognition. However, cognition is perceived as universal and its description is a priori to explanation.
Positivism considers sciences to be based solely on empirical observations and, therefore, immaterial entities cannot be studied. Furthermore, positivists consider only those statements that can be proven to be true or false as valid. Verification is essential and much emphasis is placed upon the logical structure of scientific theory and probability.
Post-structuralism, chronologically following structuralism before reacting against it, uses deconstruction as a method. Unlike structuralism, it is not reductionistic. Symbols have an unlimited number of signifiers, which can be read according to preference. Post-structuralism is not a strict school. Derrida, Foucault and Bourdieu are post-structuralists.
Pragmatism emphasises the importance of human action. According to pragmatists, knowledge is acquired through a series of transactions in which a researcher acts as an active agent. Pragmatism acknowledges the plurality of possibilities when explaining things. Furthermore, the aims of the research are always more important than the means of reaching them. Although pragmatists generally share these ideas there are also important differences in their thinking, especially when discussing the importance of reason and facts (cf. Goodman 1995).
Relativism states that all arguments and points of view are equally valid and truth or justification is relative to the individual.
Bhaskar (1979) advocated transcendental realism, a philosophical stand that defends the possibility of studying nonmaterial entities (e.g. state, marriage), which are not necessarily directly empirically observable. By separating natural and social objects and by studying them accordingly, social sciences can be viewed as a separate academic discipline. Furthermore, realism suggests that research is not totally objective but changes according to temporal and geographical backgrounds and increasing academic knowledge. Every research process is seen as a hermeneutic spiral, characterised by reflexivity.