All Brain, No Soul?

Has Science Eliminated the Soul?

A soul, progressivists say, is an explanatorily useless appendage; it is excess ontological baggage better left at the bus station.1

It seems to me that part of what gives rise to this view is thinking that the materialist accounts of human nature and our mental lives are more successful than they really are. Granted, they are ontologically streamlined in virtue of having jettisoned souls and kept only brains, but it does not seem that they have actually been able to say how the brain gives rise to the richness of experience that has traditionally been attributed to the activity of the soul. How does that lump of gray and white matter do that? Have the materialists really cracked that nut, or are they exaggerating their success?

The “Hard Problem”

Perhaps one of the most effective critics along these lines is Australian philosopher David Chalmers. He distinguishes between the “easy problems” and the “hard problem” of consciousness. The easy problems, he says, are the ones surrounding the structure and operations of the brain and central nervous system. This is the stuff of brain studies, and our knowledge of those structures has increased rapidly and is now astounding. However, as Chalmers explains, even exhaustive knowledge of those structures will not explain the nature of consciousness itself. There is a feel to conscious experience. There is something it is like to be in pain, or to daydream, or to feel happy. Many philosophers and scientists believe that explaining everything involved in thinking at the level of the brain will automatically mean explaining everything there is to our mental and spiritual life. But Chalmers is unconvinced. He says:

Physical explanation is well suited to the explanation of structure and function . . . But the explanation of consciousness is not just a matter of explaining structure and function. Once we have explained all the physical structure in the vicinity of the brain, and we have explained how all the various brain functions are performed, there is a further sort of explanandum: consciousness itself. Why should all this structure and function give rise to experience? The story about the physical process does not say.2

God on the Brain

Brad Sickler

Bradley Sickler provides a timely theological, scientific, and philosophical assessment of the human brain, displaying the many ways in which the gospel informs a distinctly Christian understanding of cognitive science.

The problem of connecting mechanisms to mental life has at least two aspects. The first is the point Chalmers is making, that understanding all the physical structures underlying our mental life (assuming they do so) does not in any way explain the connection between those structures and the thoughts themselves. A thought is not like a collection of neurons. Pain is not like C-fibers firing. The mechanisms do not really do anything to explain the phenomena of conscious experience. Why should an arrangement of physical stuff like that create consciousness? Nothing in our understanding of the nature of matter or the constitution of our brains gives even the slightest hint at an explanation. At the end of the story, all a materialist has to say is, “Well . . . it just does.” It would not be predicted from even the most comprehensive understanding of the structures and mechanisms of the brain.

In fact, there is something suspicious about the whole enterprise of trying to reduce and explain the entirety of our mental lives in terms of chemical and physical processes. The hard problem focuses on the difficulty of such accounts and the slim prospects of bridging the explanatory gap between mental and physical. That is:

The task, in other words, should not lie with trying to fit the mental into the physical, but how to understand the physical in relationship to the mental. Arguably, the neuroscientist does not just have hints that she is thinking, feeling awe, and is engaged in neuroscience; she should be certain of this, and if she does not observe the thinking, feeling awe, and the active practice of neuroscience in the observable, “unambiguously chemical or electrical” brain events or any other “thoroughly physical” phenomena, that is good reason for her to believe that thinking, feeling awe, and so on are not identical with such physical events and phenomena.3

There is still simply no adequate scientific model linking the mental and physical, or explaining the emergence of the mental from the physical. Despite the correlations that everyone is fully aware of and always has been, this is an embarrassing and troubling lacuna. In the words of Christian philosopher Kelly James Clark:

After years of thought and effort, we still have no idea how the painful ache in our knees, the perception of the redness of a rose, or the sweet taste of honey arises from the brain chemicals or neural processes that are correlated with those conscious thoughts or feelings. . . . How do things with entirely physical properties cause or give rise to things with entirely mental properties? What is the relationship of the mental to the physical? We simply don’t know.4

But if the explanation is still so far from complete (or maybe hasn’t even been started), what is left of the argument against souls? Many scientists boast that they have solved the problem of consciousness by explaining all the mechanisms of the brain. We have seen that this is a false boast. But if there is a seriously hard problem that is not yet solved (and that seems to be the case), then furthermore it cannot be true that science has eliminated the soul.

Why not? Because eliminating the soul depends on solving the problem of consciousness as a necessary first step. The allegation is that we should no longer believe in souls because science has solved the problem of consciousness, leaving nothing for souls to do. As we indicated already, the soul-of-the-gaps argument is not why most people believe in souls, but even if it were, the failure to solve the hard problem means that consciousness has not actually been explained anyway. There could still be just as much explanatory work for the soul to do now as in Plato’s day. Despite all the progress in understanding the brain, its structure, and its functions, some things still elude explanation—the hard problem remains just as hard as ever.

Why Believe Something Exists?

Another problem lurks nearby. It is a more philosophical concern, but there may be an underlying presupposition about existence claims that needs to be thought through. In short, do we have reason for believing in the existence of something only if its existence is necessary for scientific explanation? That is, do we have the right to believe an entity exists only if we need it to do science? The unstated line of reasoning could be put succinctly this way: we do not need to assume a person is anything other than a body to do our best science, so there is no good reason to believe a person is anything other than a body.

We’ve just seen one problem with this kind of argument: the difficulty of living up to the extravagant promise to be able to explain our mental lives just by reference to mechanisms. But the other problem is that it is hard to see why the needs of science—and the needs of science alone—get to arbitrate our beliefs in this way. This prejudice closes the door on the possibility that we might have justified reasons for believing in the existence of something, even though the object in question (in this case, souls) has no scientific work to do. When we state it clearly, the premise is that the only possible good reasons for believing in something must be scientific.

It is hard to see why the needs of science—and the needs of science alone—get to arbitrate our beliefs.

But why should we think that? Why should we rule out, as a stipulation from the beginning, having good but nonscientific reasons for our beliefs—reasons like, for example, experience, memory, intuition, testimony, logical inference, or even divine design or divine revelation? I cannot see why we should share this prejudice, and I have never seen a convincing argument in defense of it. It is certainly not something science has concluded, nor could it be. Science could never show us that only science can determine existence claims. But if it is false that only science can determine existence claims—or even possibly false—then what is true, or at least possibly true, is that there can be nonscientific, justifiable reasons for believing in something even if it has no scientific utility whatsoever.

The upshot is that it’s not terribly relevant whether science has any use for souls. We can grant that the usefulness science has for an entity, or the extent to which scientists offer explanations of some entity’s nature, is sometimes important. Homunculi, phlogiston, caloric, the ether—these obsolete scientific notions have all been abandoned because they served no scientific purpose and mapped onto no observable objects. We need not question that it was (probably) right to discard them.5 But it is equally mistaken to conclude that every entity science does not need is therefore mythical. And again, that assumes something that has not really been shown anyway, that science has no need of the immaterial. Scientific usefulness is not the only criterion for determining whether belief in something is justified.


  1. Note that no one seems to want to take Ockham’s razor to its logical limits. If we did, we would all end up as solipsists, people who believe that only they exist and everything else is merely an aspect of their own minds. That thesis can be made to fit with all our experiences and all the available data, and it has the most ontological parsimony possible—the existence of just one single thing. The razor is only of relative and limited value.
  2. David J. Chalmers, The Conscious Mind: In Search of a Fundamental Theory (Oxford: Oxford University Press, 1996), 107.
  3. Charles Taliaferro, “The Promise and Sensibility of Integrative Dualism,” in Contemporary Dualism: A Defense, ed. Andrea Lavazza and Howard Robinson (New York: Routledge, 2014), 201–2.
  4. Kelly James Clark, God and the Brain: A Rationality of Belief (Grand Rapids, MI: Eerdmans, 2019), 19.
  5. Though, for the record, I’m not convinced there is no ether.

This article is adapted from God on the Brain: What Cognitive Science Does (and Does Not) Tell Us about Faith, Human Nature, and the Divine by Brad Sickler.

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