Two basic types of reasoning underlie all of science—deductive reasoning and inductive or inferential reasoning. Deduction involves reasoning from a set of starting assumptions or general principles to a specific future observation. Induction requires reasoning from a limited set of observations to draw conclusions about things that have not been observed or to derive general principles. That is, induction (inference) is the process by which researchers attempt to learn what the general principles or scientific laws are.
Deduction will fail if one or more of the general assumptions is false. If one has the following starting assumptions:
- All cows give milk.
- Ferdinand is a cow.
The deduction that “Ferdinand gives milk” follows logically. If one were to observe Ferdinand and find out that he does not give milk, one ...