Inductive Logic

established by repeated observations. A Secondary Induction is the conclusion of a syllogism of which one premise is a primary induction, and the other premise is the statement of an observed fact. When, for example, it has once been admitted, as a primary induction, that specific gravities are constant, a single experiment upon a newly discovered metal is sufficient to establish its specific gravity to the satisfaction of the scientific world. The single observation is combined deductively with the primary induction, thus:? All specific gravities are constant; The specific gravity of this piece of Rubidium is 1.5; Therefore, the specific gravity of Rubidium is always 1.5. This illustration shows in an interesting manner how induction and deduction are combined. There is discovery here, but it is not reached by anything peculiar in the method of inference; that is simply deductive. But each of the premises records a discovery made by observation ; hence the syllogism is inductive. It hasbeen objected to such syllogisms, that the universal proposition could not be affirmed unless we already knew the conclusion, and that consequently there is only an apparent, and not a real advance in knowledge. The reply is, that no reasoning can ever make a substantial advance in knowledge ; to give knowledge is the function of intuition and observation alone. Reasoning can only display explicitly what was already involved implicitly. There is, however, in this case w...