Human spontaneous non-demonstrative inference is not, overall, a logical process. Hypothesis formation involves the use of deductive rules, but is not totally governed by them; hypothesis confirmation is a non-logical cognitive phenomenon: it is a by-product of the way assumptions are processed, deductively or otherwise. (Sperber and Wilson, p. 69).
From a Peircean standpoint this raises the question of abductive reasoning and its role in the cycle of inquiry.
As I read him, Peirce began with a quest to understand how science works, which required him to examine how symbolic mediations inform inquiry, which in turn required him to develop the logic of relatives beyond its bare beginnings in De Morgan. There are therefore intimate links, which I am still trying to understand, among his respective theories of inquiry, signs, and relations.
There’s a bit on the relation between interpretation and inquiry and a bit more on the three types of inference — abduction, deduction, induction — in the following paper and project report.
- Sperber, D. and Wilson, D. (1995), Relevance : Communication and Cognition, Second Edition, Blackwell, Oxford, UK.