Naturalism — the Ivy League version of materialism — is popular among the learned. But can it substitute for philosophy?

In a talk first given to the Philosophy of Science Association meeting in 2008, University of Michigan philosopher Lawrence Sklar explains,

Naturalists tell us to rely on what science tells about the world and to eschew aprioristic philosophy. But foundational physics relies internally on modes of thinking that can only be called philosophical, and philosophical arguments rely upon what can only be called scientific inference. So what, then, could the naturalistic thesis really amount to?

Lawrence Sklar, “I’d Love to Be a Naturalist—if Only I Knew What Naturalism Was,” Philosophy of Science, Vol. 77, No. 5 (December 2010), pp. 1121-1137

Sklar isn’t opposing naturalism in principle. But, taken all by itself, it is a form of absolutism. That — naturally, if you like — prompts questions from thinking people. He starts us off with some:

What is there in the world? And what is it like? “Let science be your guide.” Let’s call this “naturalism.” This slogan has both a positive and a negative side. The positive side is the assertion that the results of science are adequate to answer all of our ontological questions. The negative side is the denial that there is anything to rely on outside of science that can be a guide to our ontology.

Sklar, “If Only I Knew”

The stakes are high. From a naturalist perspective, anything that isn’t a science finding isn’t knowledge.

What happens when we try to make naturalism work?

In an essay that takes its examples from issues in physics, Sklar identifies a number of practical problems with adopting that view — trust science only. For example,

But what about the notorious problem of the transience of our best accepted theories? We have the famous induction from past experience that accepted theories have their day in the sun and then are discarded in favor of improved science. And we have the quite persuasive arguments that the changes from older to newer fundamental theory often are radical in nature and force us to dismiss the ontology posited by the older theory as even some approximately correct description of the world. Worse yet, our current fundamental physics consists of a number of theories that cannot all be true since they contradict one another.

Sklar, “If Only I Knew”

It’s not just that fundamental theories in science may be wrong. They may even be incomprehensible:

But now comes the kicker. We often don’t have the faintest idea what entities and properties are being posited by our foundational physical theories. It is just those fundamental theories that are notorious for leaving us befuddled as to what kind of a world they are talking about. Our foundational theories usually exist in a scientific framework in which they are subject to multiple, apparently incompatible, interpretations. And given the interpretation you pick, your view of what the theory is telling us about the basic structure of the world can be radically unlike that of someone who opts for a different interpretation of the theory. And this is nothing new to foundational physics. Throughout the history of the science the foundational theory preferred at the moment has always been subject to the problem of multiple interpretations.

Sklar, “If Only I Knew,”

As a natural development, the need for interpretation can greatly change what the theories are understood to be and what they imply.

If so, the problem is not that naturalism (“Let science be your guide”) — taken all by itself — leads to a nihilistic universe. It may do so. But it can also lead to an incomprehensible one.

The uncertain triumph of science

We are urged by some to take heart because science will one day triumph over all of this and we will have hard and fast answers. But, given the history, perhaps this is science’s triumph. We know vastly more about the universe than in centuries past but it remains incomprehensible, if seen only from a science perspective.

For example, the greatest difficulty comes from that newer branch of fundamental physics, quantum mechanics:

The theory that screams out loudest for interpretation is, of course, quantum mechanics. And some of the proposed interpretations are quite wildly different from those we have been looking at in their structure. Positing many worlds to deal with measurement, or positing local hidden variables and instantaneous nonlocal causation to deal with entanglement, enriches the unobservable structure of the theory rather than thinning it down.

Sklar, “If Only I Knew”

In short, we are asked to believe in many worlds (the multiverse) and instantaneous non-local causes in order to make quantum theory make sense. But how does that differ substantively from being asked to believe in miracles?

Of course, the naturalist will retort that the multiverse is considered science but miracles are not. And so? Being considered science does not, by itself, provide any evidence for a multiverse. At this point, the distinction between multiverse and miracles appears self-interested and unjustified.

As Sklar sees it, science is — and must be — intertwined with philosophy. Philosophy may determine choice of theory. If so, naturalists can only really trust naturalist science. Thus they will always seek to use science’s resources to make it an expression of naturalism.

So when science media sound like naturalist sermons, that’s what they are. And that is a philosophical choice, not a necessity.