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Naturalism and its Discontents

KELLY JAMES CLARK

Every philosopher has taken his stand on a sort of dumb conviction that the truth must lie in one direction rather than another.

William James

Introduction

In 1922, the philosopher Roy Wood Sellars proclaimed, "We are all naturalists now" (1922, vii). If by "we" Sellars meant fellow philosophers or academics, his triumphant declaration, though untrue then, is closer to being true now. At the turn of the 21st century, naturalism is the reigning orthodox assumption of most faculty in most universities across the English-speaking world. In the discipline of philosophy, philosophers increasingly identify themselves as naturalists.

What exactly is naturalism? Naturalism, we will learn, admits of no single, simple definition and comes in a wide variety of shapes and sizes (depending, for example, on its commitment to the natural sciences). After distinguishing ontological or metaphysical naturalism from the considerably more modest methodological naturalism, I will discuss the historical development of ontological naturalism, as well as arguments for or against naturalism generally. Before concluding, I will take moral goodness and badness as a case study of the problems and prospects for ontological naturalism.

What Is Naturalism?

It is impossible to offer a single precise definition of "naturalism," one that captures everything that goes by the name. Defined too narrowly, it leaves out wide swaths of human thought and experience; defined too broadly, it includes many things that naturalists hope to exclude. A better approach, then, is to consider various understandings of naturalism, as well as naturalism's historical development and recent rise. As we will see, naturalism has been understood in a great many ways. Given the diversity of understandings, we will cast our nets widely and consider the many different views and ideas that fall under the banner of "naturalism," while noting uniting features that (at least most) naturalists share.

Naturalists, as might be expected, give pride of place to the natural world, to nature, and are dubious or even dismissive of claims that go beyond the natural world: so-called "supernatural" claims. These include most importantly the belief that God exists, but also beliefs in other sorts of non-natural or spiritual entities, such as ghosts and, for most naturalists, the human soul or spirit (as an entity that is independent from the brain), as well as non-natural or spiritual powers such as qi and astrological forces. So naturalists are typically atheists who reject, among other things, mind-body dualism. As such, naturalism is an ontology: it makes claims about what exists (and, perhaps more importantly, what does not). This view is frequently called metaphysical naturalism.

This rough formulation doesn't tell us too much about the commitments of ontological or metaphysical naturalists. Nevertheless, there is one way in which it is helpful. That is, we can think of naturalism as standing in opposition to allegedly "spooky" - spiritual or theistic - understandings of the world and reality. Naturalists, then, reject any appeals to divine or supernatural entities or powers in their explanation of the world. Examples include, as we've seen, the claim that God created the universe and everything it contains and that human persons are a composition of soul and body. Naturalism came to prominence as an alternative to theism as a way of explaining the world.

As with all philosophies and philosophers, there is disagreement among naturalists. What precisely is "the natural world"? Some claim that it consists ultimately of subatomic particles (Rosenberg 2011), the ultimate and indivisible material reality. If the world were constructed out of material atoms, then naturalism would be synonymous with materialism (the view that everything is matter). But science has gone beyond (or "beneath") atoms in its understanding of nature. Perhaps nature is made up not of atoms, but instead of matter and energy, or matter/energy in its various manifestations and relations. Or perhaps matter is reducible to waves or packets of energy, or even some sort of mental stuff. The point is, we don't really know just what constitutes the natural world (and thus we don't really know what lies beyond the limits of the natural world).

To be sure, naturalism is not by definition materialistic. Logical positivism, which arose out of philosophical naturalism, rejected attempts to go beyond the domain of human experience. Positivism's severe empiricism restricted knowledge (and knowledge-based reality) to sensory experience (usually called "sense data") and logical constructions of sense experience. Physical objects were considered no more than bundles of sense data. A chair, for example, is not a solid, enduring physical object (out there, in the mind-independent world); a chair, instead, is a collection of actual and possible experiences or sensations. Since experience is mental, reality for the positivist is mental. In short, for the logical positivist, naturalism (when allied with strict empiricism) entails idealism (the idea that reality is fundamentally mental).1

It's also hard to know what counts as supernatural. Most naturalists would say that God, spirits, angels, demons, and souls are supernatural entities. But, beyond these, there is little consensus. What about such apparently non-natural, immaterial things as numbers, moral facts, merely possible beings (such as unicorns or fictional characters), and other abstract entities (like the concepts "red" and "true")? Where in the natural world do we find "Murder is wrong," Pegasus, or "2 + 2 = 4" (or the number 2)?

On these matters, as well as many others, naturalists themselves disagree. Even some atheist philosophers resist the temptation to naturalism. They don't believe in God or gods, all right, but they do believe in such non-natural, immaterial entities or facts as numbers and morality, so they don't believe they can in good conscience call themselves naturalists. Some naturalists, on the other hand, believe that immaterial entities such as numbers and other abstract entities are part and parcel of the natural world (or will eventually be shown to be so).

For the discussion that follows, we will (with provisos along the way) understand naturalism in the metaphysical or ontological sense that everything that exists is included in the natural world; there are no supernatural entities. We will from now on call metaphysical or ontological naturalism, unless otherwise noted, "Naturalism."

Naturalism and Science

Some contemporary Naturalists go further, holding that scientific inquiry is the way of knowing in general and that the finally established results of science (especially physics) determine our view of reality. According to these Naturalists, the sciences are the only guide to understanding reality. Wilfrid Sellars, in a playful paraphrase of Protagoras, writes: "Science is the measure of all things, of what is that it is, and of what is not, that it is not" (Sellars 1963, 173). Such Naturalists have a correspondingly low regard for nonscientific forms of inquiry, such as those that appeal to intuition or tradition, or to religious experience and texts. Because such Naturalists believe science is the sole guide to understanding reality, they think we should apply the methodology of science to all domains of inquiry. Recent debates in metaphysics divide over those who think metaphysics should be studied/advanced independent of any considerations of science and those more naturalistically inclined who think metaphysics should take its cues from science.2

Scientific Naturalism constitutes a role reversal for traditional approaches to philosophy, which have relied on a priori theorizing about the nature and extent of reality. Philosophy comes first in the order of inquiry, on this traditional view, and science comes second; accordingly, philosophy has authority over science. But philosophy is no longer considered the queen of the sciences, sitting in judgment over scientific claims; philosophy is often now believed to be the servant of the sciences, taking its dictates as the sober and ultimate truth about the nature of Reality. Science, on this view, has authority over philosophy. Philosophy may help us understand the foundations and methods of the sciences, which scientists employ in their various practices, but science sets the limits and nature of human inquiry. Philosophy, on this view, simply accedes to the dictates of science.

Privileging science has much to commend it: there is no other domain of human inquiry that has been so remarkably successful in understanding the world and achieving rational consensus. Tradition, authority, and Holy Writ, for example, have failed to produce the rational consensus that we find in science (or any rational consensus whatsoever). Even those who affirm this or that text as Scripture find themselves with substantial disagreement as to what their Scripture teaches. Science or scientific inquiry offers what religion promised but has failed to offer: a method of inquiry for attaining rational consensus.

More than consensus, though, science also seems to be uniquely capable of attaining the truth: the universal law...