Introduction

The aim of science is to understand reality. An academic discipline, philosophy of science, is devoted to explicating the nature of science and its relationship to reality, and, perhaps predictably, both are controversial; for an excellent introduction to the issues see Chalmers (1999). In practice, however, most scientists explicitly or implicitly assume a view of scientific methodology based on the philosophy of Karl Popper (Popper 1959, 1963), in which one or more non-contradictory hypotheses about some domain of interest are stated, the validity of the hypotheses is tested by observation of the domain, and the hypotheses are either confirmed (but not proven) if they are compatible with observation, or rejected if they are not.

Where do such hypotheses come from? In principle, it doesn't matter, because the validity of the claims they make can always be assessed with reference to the observable state of the world. Any one of us, whatever our background, could wake up in the middle of the night with an utterly novel and brilliant hypothesis that, say, unifies quantum mechanics and Einsteinian relativity, but this kind of inspiration is highly unlikely and must be exceedingly rare. In practice, scientists develop hypotheses in something like the following sequence of steps: the researcher (i) selects some aspect of reality that s/he wants to understand, (ii) becomes familiar with the selected research domain by observation of it, reads the associated research literature, and formulates a research question which, if convincingly answered, will enhance scientific understanding of the domain, (iii) abstracts data from the domain and draws inferences from it in the light of the research literature, and (iv) on the basis of these inferences states a hypothesis to answer the research question.