Abduction: a philosophical scam

A philosopher will often fool himself into believing he had made a valuable contribution to knowledge by making up a fancy word. In many cases, the word conceals confusion and gets in the way of simply rejecting a bad idea and moving on. Abduction is one of those words.

The Stanford Encyclopedia on abduction, linked above, sez:

Abduction or, as it is also often called, Inference to the Best Explanation is a type of inference that assigns special status to explanatory considerations. Most philosophers agree that this type of inference is frequently employed, in some form or other, both in everyday and in scientific reasoning.

The entry then gives an example:

One morning you enter the kitchen to find a plate and cup on the table, with breadcrumbs and a pat of butter on it, and surrounded by a jar of jam, a pack of sugar, and an empty carton of milk. You conclude that one of your house-mates got up at night to make him- or herself a midnight snack and was too tired to clear the table. This, you think, best explains the scene you are facing. To be sure, it might be that someone burgled the house and took the time to have a bite while on the job, or a house-mate might have arranged the things on the table without having a midnight snack but just to make you believe that someone had a midnight snack. But these hypotheses strike you as providing much more contrived explanations of the data than the one you infer to.

This sort of thing is not inference. It’s called guessing and criticism. You notice the stuff on the table. You guess that your housemate might have made a snack and not cleared the table. You guess that a burglar might have broken in and made a snack. But the burglar would have done other stuff like ransacking the house and stealing. If the house hasn’t been ransacked and nothing is missing, then the burglar guess doesn’t explain what happened at all. The burglar guess is ruled out by criticism. If you found out that your housemate interrupted a burglar having a snack you might reconsider since that would explain the lack of ransacking. This process of guessing and criticism is concealed by the term abduction.

Abduction also smuggles in the idea that ideas can be confirmed or justified. From the start of section 2 of the encyclopedia entry:

Precise statements of what abduction amounts to are rare in the literature on abduction. (Peirce did propose an at least fairly precise statement; but, as explained in the supplement to this entry, it does not capture what most nowadays understand by abduction.) Its core idea is often said to be that explanatory considerations have confirmation-theoretic import, or that explanatory success is a (not necessarily unfailing) mark of truth.

An idea is either true or false. You can use an argument to point out a problem for an idea. In the example of the snack stuff on the table, the lack of ransacking for the burglar theory. But the argument doesn’t show that anything is true or make truth of some particular idea more probable, or make it better in any way. It just creates a problem for an alternative idea.

Some people complain that this is too restrictive. They might think you can apply an idea without it being true. For example, there is no theory of gravity compatible with quantum mechanics. So QM has a problem. Should we never use it?  But QM is used in the semiconductor industry to help design computer chips. So then the rejecting stuff that is criticised idea seems too rigid. But we can explain why QM should work for chips even though there is no QM theory of gravity. Gravity interacts very weakly with the chips compared to other forces. So you would have to put the chip in a very strong gravitational field before a quantum theory of gravity would be relevant to its performance. So the criticism of using QM on computer chips has been answered and we can keep doing it. More generally, the solution to alleged strict restrictions imposed by criticism is to look at the criticism as an explanation and consider the relevance of that explanation to the problem you are trying to solve. If the explanation behind the criticism is irrelevant then the criticism has been answered.

Anyway, abduction is a scam. Philosophers use it to fool themselves into thinking they understand knowledge and have good ideas about it when they don’t.