Inference to the Best Explanation

According to Ch 8. "Inference to the Best Explanation: The General Account" and Ch 9. "Inference to the Best Explanation: Examples" in John D. Norton, The Material Theory of Induction. ms

Two Step Model

(Constructed after an examination of many standard examples of IBE in science.)

Step 1. Preference for the Better Explanation

The favored hypothesis is adequate to the evidence, most commonly in the sense that it deductively entails the evidence.

The foils, that is, the alternatives, are judged inadequate in one of two ways:

Contradiction: The evidence at hand may directly contradict the alternative; or the evidence supplemented by specific background facts may contradict the alternative.

Evidential debt: to accept the alternative requires us to accept further assumptions for which we have no evidence.

The essential point is that the favoring invokes no explanatory notions.

Step 2. From Comparative to Absolute: Better is Best

The safest case arises when background assumptions assure us that the hypotheses or theories we have considered are exhaustive.

The most difficult case is the most common. It is when the inference from better to absolute best is made, even though the scientist have no clear grasp of the full range of hypotheses or theories possible.

Often this step is not taken explicitly.

Major Claims

No distinctively explanatory notions appear. There is no attribution of special inductive powers to some specific notion of explanation. Much of the important inductive work is carried by elimining the foil.

The present literature in IBE is degenerating as far as science is concerned. The examples are overwhelmingly ones concerning human action, where the role of the foil is minimal. They are poor models for abductive inferences in science. (Footprints in the snow vs origin of species)

Catalog of Case Studies

Abduction	Foil	Foil eliminated	Generalization from better to best
Darwin on the origin of species	Independent creation	Refuted by traits without function	Tacit assumption of exhaustive choice
Lyell’s uniformitarian geology	Geologies using presently unknown causes	Novel causes incur an undischarged evidential debt.	Known versus unknown causes is exhaustive
Thomson for cathode rays as charged particles	Cathode rays are processes in the ether.	Contradiction with experiment: Ether waves would not be bent by a uniform field	Tacit assumption of exhaustive choice
Lenard for cathode rays as ether processes	Cathode rays are processes in matter	Contradiction with experiment: cathode rays in evacuated tubes	Choice between matter and ether posed as exhaustive dilemma.
Einstein’s explanation of Mercury’s anomalous motion	Many. Modifications to Newtonian theory. Unobserved masses.	Contradiction with experience. Undischarged evidential debt.	Step not taken.
Cosmic background radiation from the big bang	Alternative cosmologies, especially steady state cosmology	Empirical failure	Taken tacitly
Lavoisier’s oxygen chemistry.	Phlogiston chemistry.	Contradiction. Matter has weight (gravity), but phlogiston has levity.	Fact (matter has weight) is one of many warranting facts.
Wave theory of light.	Newtonian corpuscular theory.	Undischarged evidential debt. Contradiction with experiment.	Complicated.