What Are Sam Harris’s Metaphysical Presuppositions?

Post Author: Bill Pratt

It is impossible to ground a theory about the source of objective moral values and duties without recourse to metaphysics. Philosopher David Oderberg reminds us that it is “impossible to know how the world ought to go, more specifically how one ought to act (or what makes a state of affairs or action good, or worthwhile, praiseworthy, etc.) without prior knowledge of how the world is.” Metaphysics tells us how the world is.

So what are Sam Harris’s metaphysics? How is the world, according to Sam Harris?

Rather than argue for his metaphysical view, Harris, for the most part in his book The Moral Landscape, merely presupposes that his ontology is correct.  Harris’s worldview can be best described as metaphysical naturalism, which is roughly the view that what exists is that which can be described by physics, chemistry, and biology.  Harris reveals that he is a metaphysical naturalist in several ways.

First, recall his thesis summary statement: “Conscious minds and their states are natural phenomena, of course, fully constrained by the laws of Nature (whatever these turn out to be in the end).” Second, Harris claims that the well-being of conscious creatures “must lawfully depend upon events in the world and upon states of the human brain.”

In one particularly telling passage, Harris asks the reader to imagine a world where only two people existed, a fictional Adam and Eve.  How might the moral landscape look in that situation?

In fact, there are, by definition, paths that lead to the worst misery and paths that lead to the greatest fulfillment possible for these two people— given the structure of their respective brains, the immediate facts of their environment, and the laws of Nature. The underlying facts here are the facts of physics, chemistry, and biology as they bear on the experience of the only two people in existence.

For Harris, the ontological foundation of ethics consists in brain states, the physical world surrounding human beings, and the natural laws which constrain the physical world.  Again, all of these aspects of reality fit comfortably under the label of metaphysical naturalism.

Might Harris allow other aspects of being into his metaphysics?  How about the notion of a Creator-God?  Harris rules out the existence of God almost immediately in his book as he explains that one of his primary goals is to provide a moral theory which has no need of God.

What about immaterial human souls?  For Harris, the existence of a soul, which is “metaphysically independent of the brain, seems untenable given that damage to the relevant neural circuits obliterates these capacities in a living person.” In other words, neuroscience has shown that the “soul,” and thus consciousness, really just is neural circuits.

How about the existence of metaphysical principles such as nature, form, or essence?  Harris seems to disavow the existence of essences when he says, “I am certainly not claiming that moral truths exist independent of the experience of conscious beings— like the Platonic Form of the Good— or that certain actions are intrinsically wrong.”

It seems that Harris’s ontology allows nothing beyond what physics, chemistry, and biology reveal.  It remains to be seen whether Harris’ metaphysical views can provide an adequate ground for the good.