As the name indicates there are at least two parts to the hypothetico-deductive (h-d) method: a hypothetico part in which a hypothesis or theory, arising from whatever source, is proposed for test, and a deductive part in which test consequences are drawn from the hypotheses. Unmentioned in the name of the method is a crucial third part in which consequences are deduced and compared with experiment or what we can observe. e consequences pass or fail when the comparison is made. In some cases the hypothesis might be invented to account for some already known fact(s); it is then tested by deducing further consequences from it, which are then subject to test. An important question arises about how the pass or fail verdict is transmitted back to the hypothesis; this creates problems for the h-d method, as will be seen. e test consequences need not be obtained only by deduction; if the hypotheses are statistical then the consequences are inferred by non-deductive, or inductive, reasoning. So a better name might be the hypothetico-inferential method, to cover both cases of deductive and non-deductive inference.