Discussion Grounds

Luke,

Greetings. I think you have described the situation well. Neither of our definitions is fully adequate. I see now that if one takes my (B) and (C) as conjunctive with (A), one ends up with heuristic explanation, which is adequate in many cases; but what we’re after is what is true, not what’s merely useful.

Your (A*) revision of my (A) is an improvement, and I suppose we could improve it still further with (A**):

(A**, Heuristic) By knowing x, where x is relevant to y’’s causal background, we understand y better than by not knowing x.
[(B) and (C) must conjunctively accompany (A**)]

or

(A***, Ultimate) By knowing x, where x is true and x is relevant to y’s causal background, we understand y better than by not knowing x

The second of these obviates the need to include either (B) or (C). What I like about it is that it emphasizes that explanation is more about increasing causal (as you rightly pointed out) understanding than it is about anything else. For the record, I accept Aristotle’s four-fold approach to understanding causation: material, formal, efficient, and final. This clashes with some scientific reductionists’ view that for many phenomena there are only material and efficient causes. I am not predicting we will have a disagreement over that, and I suggest we not try to sort this out in advance (unless you happen already to agree with Aristotle on this). If the disagreement arises, let’s deal with it then.

I think we have it sorted out well enough to progress, though I want to add these two remaining items to the list of explanatory virtues:

7. Explanatory scope: a good hypothesis will explain a wide range of data (a wider range than rival hypotheses)

8. Explanatory power: a good hypothesis is one that supports the epistemic probability of the evidence

In many cases the test (epistemic virtue 1) of hypotheses must be in the form that’s suitable to inference to the best explanation (IBE). With IBE, in the absence of other tests, one looks at the other explanatory virtues and determines which of two or more rival hypotheses better meets those virtues. There is, for example, no “test” for either the existence or non-existence of God as “test” is commonly understood. There is no “test” for the actuality of claimed historical events. There is, however, evidence in the world, in experience, and in documents, and there are rival hypotheses; and the test must be in the form, which of the rival hypotheses better explains the evidence?

In Letters 9, 10, and 11, I presented a set of phenomena, evidences relating to the human condition, and I suggested that Christianity explains them better than does atheism. I did not formalize it according to these explanatory virtues, since we had not developed the list yet. Would you like me to do that now, or is the case I’ve made on this point already in a form that you are ready to respond to?

Regards,

Tom