Discussion Grounds

Tom,

Despite the fact that inference to the best explanation is far less developed than deductive logic,¹ it looks like we’re honing in on some agreement over what it means to say that some hypothesis or theory is the best explanation of some phenomenon. We might say that:

x is the best explanation of y if it is the case that:

(A) if x were true, then by knowing x we would better understand x’s causal background than by not knowing x [i.e. x is a potential explanation of y],

and if it is also the case that

(B) x possesses the following explanatory virtues to a greater degree than any other known potential explanations of y: testability, consistency with background knowledge, past explanatory success, simplicity, ontological economy,² informativeness, predictive novelty,³ explanatory scope, and explanatory power.

Is that agreeable?

There is much left to say about the value of each of our explanatory virtues, but we can address those points as they come up in our debate.

You’re right to guess I only accept material causes and efficient causes. I don’t think it will be very interesting for you to argue that Christianity offers a better explanation for the telos of humanity than naturalism does. In the same way, it wouldn’t be very interesting for you to argue that Christianity offers a better explanation of souls than naturalism does. As much as possible, each of us are going to have to appeal to evidence from our shared ontology if we are going to have a chance at persuading the other. That is usually the project of natural theology and natural atheology, anyway.

Tom, in order to keep our debate manageable, I hope you can start with one particular phenomenon of the human condition – one on which we agree – and then argue that Christianity provides a better explanation for that phenomenon than naturalism does. You can do the same with other phenomenon of the human condition in the future if you like.

1. For example, see Peter Lipton, “Inference to the Best Explanation“ (2000). Lipton’s “What Good is an Explanation?” (2004) is also useful. [↩]
2. I changed “ontological simplicity” to “ontological economy” just so that it was better distinguished from the explanatory virtue simply named “simplicity.” [↩]
3. I added this one because I doubt you’ll disagree with it. I’m using the term as Richard Swinburne uses it in Is There a God? (1997). Predictive novelty refers to a theory’s ability to predict previously unknown facts. For example, Einstein’s theory of gravity predicted as-yet unobserved phenomena that Eddington later observed to be true. [↩]