Inductive reasoning is a type of reasoning that moves from specific to general. There are two types of inductive argument that constitute legitimate support for a general general conclusion. One is complete induction where one examines all possible relevant case. The other is working from a representative sample. Thus in making an argument inductively concerning why the drinking age should be higher, you would start by doing the research to prove that people who drink at a younger age harm either themselves or others and then argue on the "harm principle" that there is justification for curtailing individual liberty by raising the drinking age.