As far as what “gives a rule to abduction”, as Peirce styled a question I found echoed in minds of inquiry from W.S. McCulloch to Noam Chomsky, Peirce had already given the answer in the form of his maxim of pragmatism, which sets the bar that any concept or thesis must pass in order to serve the purpose of inquiry.
That’s the short answer for anyone who’s heard this story before and needs but the slightest jog of memory. But the circumstance that stirred me to pipe up this time around arose in a dispute between folks who probably haven’t heard that line before and who seemed to be laboring under all sorts of misconceptions about Peirce’s perspective on the logic of science as it applies to the nature of physical theory.
So there I merely tried to make the following points:
- The abductive step is by no means the whole of inquiry. Its end lies at the end of the steps that come after.
- The abductive step is sui generis and does not reduce to any mix of deductive or inductive reasoning, for example, Bayes’ theorem or its application to probabilities.
There are other points having to do with (3) the creative role of abductive reasoning in concept formation, (4) its inaugural role in breaking ground for the initial formation of conceptual frameworks and theories, (5) its catalytic action at times when paradigms get mature or unstable or otherwise ripe for shifting. But sufficient unto the day, as they say.