- Correct reasoning or the study of correct reasoning and its foundations.
- The relationships between propositions (supports, assumes, implies, contradicts, counts against, is relevant to . . . ).
- The system of principles, concepts, and assumptions that underlie any discipline, activity, or practice.
- The set of rational considerations that bear upon the truth or justification of any belief or set of beliefs.
- The set of rational considerations that bear upon the settlement of any question or set of questions.
The word “logic” covers a range of related concerns all bearing upon the question of rational justification and explanation. All human thought and behavior is to some extent based on logic rather than instinct. Humans try to figure things out using ideas, meanings, and thought. Such intellectual behavior inevitably involves “logic” or considerations of a logical sort: some sense of what is relevant and irrelevant, of what supports and what counts against a belief, of what we should and should not assume, of what we should and should not claim, of what we do and do not know, of what is and is not implied, of what does and does not contradict, of what we should or should not do or believe.
Concepts have a logic in that we can investigate the conditions under which they do and do not apply, of what is relevant or irrelevant to them, of what they do or don’t imply, etc. Questions have a logic in that we can investigate the conditions under which they can be settled. Disciplines have a logic in that they have purposes and a set of logical structures that bear upon those purposes: assumptions, concepts, issues, data, theories, claims, implications, consequences, etc.
The concept of logic is a seminal notion in critical thinking. Unfortunately, it takes a considerable length of time before most people become comfortable with its multiple uses. In part, this is due to people’s failure to monitor their own thinking in keeping with the standards of reason and logic. This is not to deny, of course, that logic is involved in all human thinking. It is rather to say that the logic we use is often implicit, unexpressed, and sometimes contradictory.« Back to Glossary Index