The deductive reasoning reviewed so far is, of course, not the only kind of reasoning that has been studied. In this chapter and the next we shall look at two important, and closely related, forms of thinking: hypothesis testing and induction. Hypothesis testing is also related to the forms of deductive thought we have considered in the preceding chapters: for instance, a scientific, medical, or other hypothesis could be put into conditional (if p then q) or quantified (all A are B) form, and its implications checked against the observed facts. Thus, some authors consider the selection task as a hypothesis-testing problem. Hypothesis testing is also related to causal reasoning, and to the philosophy of science.