A term used by Charles Peirce to denote the process of inquiry in which a hypothesis is formed or generated;
The result of such a process – the conclusion reached or the assumed guess, respectively, is called retroduction and hypothesis.
The word “abduction” has more than one meaning and is ambiguous.
Related: Ambiguity
These meanings are often confused or merged. In one case, the term means an act of coercion or non-compliance with someone or something; in semiotics, it concerns the discovery of some law or other factor that would understandably represent a phenomenon.
In addition, abduction, as in Peirce‘s semiotics, is primarily a logical (rather than psychological) process. While psychology is a descriptive science, logic is a normative science.
Most of Sherlock-Holmes’s so-called deductions are, strictly speaking, abductions – guesses about what’s going on. These are guesses, carefully delineated and then carefully checked. In classifying abduction as judgment, Peirce argues that, along with deduction or induction, abduction lends itself to logical analysis and evaluation; it can be broken into pieces or pieces, it can also be valued in the light of its function (explaining the mysteries in a credible way).
Abduction differs from the other two forms of judgment.
The deduction is the logical operation in which we separate the necessary consequences from some purely hypothetical situations (for example, if it is true that A is greater than B and B is greater than C, then it follows that it is also true that A is greater than C).
Induction is the operation in which we test hypotheses in terms of the consequences of deduction; abduction is where hypotheses are made in the first place. In other words, deduction proves that something must be the case; induction shows that something is in fact the case; and abduction, in turn, suggests that something could be the case. (CP 5.171).
Although the consideration of abduction as a form of judgment suggests that for Peirce it is logic, it should not be taken simply as a recipe for making unshakable guesses. For example, there are several ways to improve the odds of playing “Twenty Questions”; one such way is to go from the general to the particular. The logic of discovery, in Peirce’s sense, is that at least it is nothing more – but it is nothing less than a set of rules and processes by which we increase our chances of guessing correctly.
