How would you reply to this argument that scientism is not self-refuting:
"Scientism has been always been successful in the past; any supernaturalistic explanations used by our progenitors have been replaced by naturalistic explanations. Never has a supernaturalistic explanation superseded a naturalistic one. Since the predictions of scientism have always been later confirmed directly by the evidence, this amounts to a good inductive argument for scientism. So Craig is wrong that scientism cannot be scientifically proven because scientism's own success and adoption by scientists serves as evidence for its truth."
Basically, the person I quoted is a friend of mine who treats scientism itself as a scientific theory and argues that it is inductively warranted and evidenced. Hence, he alleges that it is not self-refuting. He also thinks that this strategy can be extended to evidentialism (I found this out when I tried explaining Reformed Epistemology to him). He rejects your other argument against scientism that science cannot account for mathematical truths (because he is an empiricist about mathematics and logic), morality (he is a nihilist), and aesthetics (he is a nihilist about that too). The most disturbing thing is that I have seen other self-styled empiricists on the Internet run similar arguments to these. How should I respond these types of assertions?
Neel, your friend is confusing scientism (an epistemological thesis) with naturalism (an ontological thesis). Scientism is the view that we should believe only what can be proven scientifically. In other words, science is the sole source of knowledge and the sole arbiter of truth. Naturalism is the view that physical events have only physical causes. In other words, miracles do not happen; there are no supernatural causes.
These theses are obviously different. A person could accept other sources of knowledge besides science, such as rational intuition, and still be a naturalist. Similarly, one could hold to an epistemology of scientism and yet be a non-naturalist. For example, the late W. V. O. Quine, who held that physical science is our only basic source of knowledge, freely admitted, “If I saw indirect explanatory benefit in positing sensibilia, possibilia, spirits, a Creator, I would joyfully accord them scientific status too, on a par with such avowedly scientific posits as quarks and black holes.”i Thus, scientism does not imply naturalism, nor does naturalism imply scientism.
So leaving aside for the moment the question of naturalism, what problems are there with scientism? There are two which are especially significant. First, scientism is too restrictive a theory of knowledge. It would, if adopted, compel us to abandon wide swaths of what most of us take to be fields of human knowledge. Your friend admits this with regard to moral and aesthetic truths. On his view there is nothing good or evil, right or wrong, beautiful or ugly. But is it plausible to think that there are no aesthetic or moral truths? On your friend’s view there’s nothing wrong with torturing a little girl to death. Why should we accept such a conclusion simply because of a epistemological restriction? Isn’t this a signal that we need rather to broaden the scope of our theory so as to encompass other types of knowledge? Your friend says he will treat logical and mathematical truths as merely empirical truths. Good luck! Truths like “If p implies q, and p, then q” or “2 + 2 = 4” are to all appearances necessary truths, not merely empirical generalizations. And what about science itself? Science is permeated with assumptions that cannot be scientifically proven, so that an epistemology of scientism would destroy science itself. For example, the principle of induction cannot be scientifically justified. Just because A has always been succeeded by B in the past provides no warrant for inferring that the next A will be followed by B. For we could be at the beginning of a chaotic series of As and Bs whose initial segment is ordered ABABAB. So trying to provide “a good inductive argument for scientism” is hopeless, since it must presuppose the validity of inductive reasoning.
Secondly, scientism is self-refuting. Scientism tells us that we should not believe any proposition that cannot be scientifically proven. But what about that very proposition itself? It cannot itself be scientifically proven. Therefore we should not believe it. Scientism thus defeats itself. Your friend’s proffered argument for scientism is not an argument for scientism but for naturalism. He’s arguing that the assumption that there are only natural causes operative in the world has achieved extraordinary success in contrast to the assumption that there are supernatural causes as well. That has no relevance to the epistemological question before us. It is at best an argument against miracles. Actually, it’s much weaker than that: it is at best an argument for methodologicalnaturalism, that is to say, the view that in doing natural science we should assume that all physical events have only natural causes. The methodological naturalist needn’t be a metaphysical naturalist, that is to say, he needn’t deny that miracles occur or that supernatural entities exist. He contends merely that they are not the concern of science. Science just is the search for natural causes or explanations of phenomena. This methodological thesis is one which a great many, if not most, Christian scientists agree with. So your friend’s argument really doesn’t amount to much.
As Michael Rea has shown in his incisive book World without Design (Clarendon Press, 2002), the only defensible form of epistemological naturalism (a.k.a. scientism) is that it is a methodological decision to follow a research program which takes the physical sciences to be the only basic source of knowledge. As such it cannot be justified. It just represents the naturalist’s personal decision to adopt a certain research program. Anyone else can with equal right adopt a different research program which may accept additional sources of knowledge in addition to the physical sciences.
One final note about your friend’s argument for naturalism: of course, no supernaturalistic explanation has ever superseded a naturalistic one! That’s guaranteed by science’s assumption of methodological naturalism. It prohibits supernatural explanations from even being included in the pool of live explanatory options. Thus it’s impossible for a supernaturalistic explanation to supersede a naturalistic one! Only for theorists who are willing to challenge the assumption of methodological naturalism, like creation scientists or advocates of Intelligent Design, is there the possibility that a naturalistic explanation might give way to a supernaturalistic explanation. They argue that it should in the case of biological complexity. But because they are working with a conception of science outside the mainstream (namely, they reject methodological naturalism), it’s highly unlikely that their view will ever become the paradigmatic view of science, no matter what the evidence.
I note as well that in nearly two thousand years no naturalistic explanation has managed to supersede the resurrection of Jesus, a supernaturalistic explanation if there ever was one, of the facts concerning the fate of Jesus of Nazareth.