Inquiry

Inquiry is any process intended to increase knowledge, settle uncertainty, or address a problem. A theory of inquiry explains the different kinds of inquiry and how each kind reaches its goal.

Theories of inquiry often examine three types of reasoning. Deduction, as described by Aristotle, works when three terms are arranged so that the last is fully contained in the middle, and the middle is fully contained in or excluded from the first. This arrangement yields a perfect syllogism. For example, if A applies to all B, and B applies to all C, then A necessarily applies to all C. Induction establishes a relation between one extreme term and a middle term by using the other extreme.

For instance, proving that A applies to B by using C is how inductions are carried out. Abduction, or reduction, occurs when it is clear that the first term applies to the middle, but it is not obvious that the middle applies to the last term, yet this connection is at least as probable as the conclusion. Alternatively, it occurs when there are few intermediate terms between the last and the middle.

In both cases, the process brings us closer to knowledge. Aristotle gave examples: if A is "what can be taught," B is "knowledge," and C is "morality," then it is evident that knowledge can be taught, but whether virtue is knowledge is unclear. If the link between B and C is at least as probable as the link between A and C, then abduction brings us nearer to knowledge. Another example: if D is "to square," E is "rectilinear figure," and F is "circle," and there is only one intermediate term between E and F—that the circle becomes equal to a rectilinear figure by means of lunules—then we approximate to knowledge.

Inquiry in the pragmatic paradigm

In the pragmatic paradigm, associated with Charles Sanders Peirce, William James, John Dewey, and others, inquiry is closely tied to the normative science of logic. Peirce drew from classical logic and Kant, refining his ideas alongside the early development of symbolic logic by Boole, De Morgan, and himself, to address the nature and conduct of scientific reasoning. Borrowing concepts from Aristotle, Peirce examined three fundamental modes of reasoning in inquiry: abduction, deduction, and induction. Roughly, abduction generates a likely hypothesis or initial diagnosis in response to a phenomenon or problem.

Deduction clarifies, derives, and explicates the consequences of that hypothesis. Induction tests the predictions against the data. The classical and pragmatic treatments divide inference into three parts, differing from accounts that recognize only two.

These three processes typically operate in a cycle, systematically reducing the uncertainties that initiated the inquiry, and, if successful, leading to increased knowledge or skills. In pragmatic thought, everything has a purpose, and the purpose of inquiry is to reduce doubt and reach a state of belief, which is usually called knowledge or certainty. The three kinds of inference form a cycle that must be understood as a whole; none makes complete sense in isolation.

For example, abduction generates guesses that deduction can explicate and induction can evaluate. This places a constraint on hypotheses: they must be the kind that can submit to reason and be defeated by reality. Similarly, each type of inference fulfills its purpose only within its proper role in the whole cycle. Though these processes may be studied separately, the integrity of inquiry places strong limits on their effective use.