The problem with trying to eliminate metaphysics from science is that, as the French philosopher Émile Meyerson argued a century ago, history never exhibits such a tidy distinction between “metaphysics” and “science.” Newton invoked divine intervention to explain his concept of an invisible force acting instantaneously across great distances, considered space to be an attribute of God, and dedicated much of his life to alchemy.

In 1781, Immanuel Kant announced that metaphysics, once queen of the sciences, had been dethroned.

Natural science was the usurper. This is the Enlightenment’s own Creation story: metaphysics was banished for having unlawfully tasted the fruit of the tree of knowledge, making room for scientific knowledge. We have not shaken this myth.

The idea that science and metaphysics are totally distinct — what Stephen Jay Gould called non-overlapping magisteria — is comforting. Scientistic thinkers, such as the New Atheists, take comfort in the notion that their knowledge is purely empirical (and not metaphysical). The religious, meanwhile, take comfort in the notion that religious truths are immune to empirical disconfirmation — precisely because they are metaphysical and not scientific.

But the truth is messier.

The fact is the queen was never dethroned, but merely disguised. Metaphysics, as Kant knew, could never be eradicated, only redirected. Like the monarch who welcomes constitutional reform in lieu of revolution, the queen of the sciences subjected herself to a new law: the mercurial tribunal of experience. Experimental science became the new face of metaphysics — and this meant that metaphysics became something quite different.

Once upon a time we asked philosophers for answers to certain questions: “what is time?” “is the universe eternal?” At that point, science and philosophy were not distinct disciplines; physics was philosophiae naturalis, subordinated to metaphysics or theology — what Aristotle called “first philosophy.” ‘Scientia,’ after all, simply means ‘knowledge,’ knowledge of the surest sort, and it was through philosophy that one attained it. Philosophers had plenty of answers: “time is the moving image of eternity” (Plato) “time is the measure of motion” (Aristotle), “time does not exist” (Chrysippus). Philosophers still have answers, about which they still disagree, including whether philosophy can or even ought to answer such questions.

So we stopped asking philosophers when scientists promised something more. Scientific explanations — “time is the fourth dimension of a semi-Riemannian manifold,” “the universe began rapidly expanding from a state of high density approximately 13.8 billion years ago” — have many virtues that philosophical answers do not. They exhibit precision (thanks to their mathematical nature) — in particular, they are precise even about uncertainty — fecundity (thanks to their predictive power and technological implications), and partial consensus (thanks to agreed upon experimental procedures).

But that’s not all: for better or for worse, such explanations now provide the backbone for our modern metaphysical image of the cosmos.

How can this be? We learn in elementary school that scientific theories are formulated according to the “scientific method:” a presuppositionless inquirer formulates a hypothesis based upon pure observations and goes on to verify it via experiment. Hypotheses are just a necessary evil in a procedure that, unlike the “soft” sciences or the humanities, eschews extra-empirical reasoning in favor of strictly “verifiable” claims. But this, like many things we are told in elementary school, is a fairy tale.

Nevertheless, the fairy tale is persistent. When college-level physics students learn the classical laws of motion, they are often told that Aristotle’s theory of motion was blatantly wrong because it was based on pure reasoning rather than observation. The implication is that “our” theory of motion is correct because it is based on observations. (Let’s leave aside the fact that, in this case, “our” theory means the Newtonian theory, which is, nowadays, understood to be an approximation at best).

Of course, in saying that Aristotle didn’t make observations, the teacher commits an historical error. Aristotle took all knowledge to be rooted in sensation and gathered an enormous range of empirical data himself. But, more importantly, the teacher commits a philosophical error. As Thomas Kuhn pointed out, mere observation confirms Aristotle’s theory of motion to a great extent. In ordinary circumstances, heavy bodies do fall faster than light ones. Aristotle was not wrong because he failed to make observations; he was so because he only made observations.

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