Reason usually has three different meanings. (1) It can signify the mind, or an agency used in thinking. For example, we may ask someone to use reason rather than emotions. (2) Reason also refers to the evidence for a belief, opinion, or judgment. We may demand a reason for a person’s belief that someone is a thief. (3) Reason may refer to a process of arriving at a decision or a conclusion. For instance, we may say that a jury was reasoning correctly when it decided a defendant was guilty.
Reasoning can be inductive or deductive. People use inductive reasoning when they see a puddle of water and infer that it has rained recently. Inductive reasoning is not conclusive. The evidence only makes the conclusion probable. See Inductive method .
People use deductive reasoning when they assert that oxygen is present in a place because life is present there and because life requires oxygen. Deductive reasoning shows what else must be true if the initial beliefs are true. See Deductive method .