During his recent debate with William Lane Craig on the topic “Is there Evidence for God,” physicist Lawrence Krauss claimed that only empirical data is an acceptable form of evidence. Given our culture’s proclivity toward empiricism and naturalism, I doubt that most found Krauss’ epistemic principle controversial. I think it is highly controversial, however.
First, to say empirical data alone counts as evidence is to relegate the entire discipline of philosophy to the ash heap of epistemic irrelevance.
Second, it seems to have escaped Krauss’ attention that his epistemic principle is itself a philosophical claim, not an empirical finding. Indeed, what empirical evidence could he offer in its support? None. There is no empirical evidence to justify his principle. How, then, could someone like Krauss persuade those who do not accept his philosophical principle that they ought to accept it? He would either have to appeal to philosophy to show that the principle is rational, or acknowledge that there is no reason someone should accept his principle. If the former, then he violates his own principle because he is using philosophical reasoning as evidence. If the latter, there is no reason to accept his principle, and thus no reason to think empirical data alone counts as evidence.
Thirdly, it is obvious that empirical data is not the only kind of evidence available. If it were, then the vast majority of what we consider historical knowledge must be considered mere speculation since little of what we know about history can be proven empirically. The same is true of moral values, logical laws, and mathematical principles. Clearly we have knowledge of these things, and yet we lack empirical evidence for them. Indeed, empirical evidence is not even possible for such things. As such, I find no basis for Krauss’ incredible claim that only empirical evidence is valid in regards to the debate over God’s existence.