I’m already getting pushback against my free online book Mind-Body Problems: Science, Subjectivity & Who We Really Are. Tom Clark knocks me for not giving more credit to straight-forward materialism, or naturalism, as he prefers to call it. Meanwhile, Deepak Chopra, while defending an anti-materialistic view, compares my pluralistic approach “to giving every player in a junior soccer match a trophy.” Good one, Deepak! See “Discussion” for these and other comments.

It was precisely because people have divergent views of the mind-body problem that I decided to write a book about it. The mind-body problem is the knottiest of all mysteries. It encompasses puzzles such as consciousness (which David Chalmers calls “the hard problem”), free will, the self, morality and the meaning of life (which Owen Flanagan, a subject of my book, calls “the really hard problem”).

Another way of posing the mind-body problem is simply by asking, Who are we, really? Sages as diverse as Buddha, Plato, Kant and Douglas Hofstadter (to whom I devote a chapter of Mind-Body Problems) have offered answers to this question. In the early 1990s, Francis Crick said that science had finally given us the tools to solve the problem once and for all. In his 1994 book The Astonishing Hypothesis, he spells out the implications of his ultra-materialistic creed:

“You,” your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules. As Lewis Carroll’s Alice might have phrased it: “You’re nothing but a pack of neurons.”

Crick implied that science would solve the mind-body problem by investigating the physiological underpinnings of mental phenomena, just as it solved problems like speciation, heredity and metabolism. I once thought Crick was right, but I've changed my mind, he's wrong. In Mind-Body Problems I argue that science cannot provide a single, objectively true solution to the mind-body problem, because our responses to the problem will always be at least partially subjective, a matter of taste as well as truth.

This is a crucial point, so let me elaborate on it. Some mind-body questions can in principle be empirically resolved. For example: How do we see, hear, remember? Scientists can pinpoint neural operations underpinning these functions in humans and other creatures and reproduce them in machines. At some point, the answers might become so compelling that reasonable people call them true.

But why, when we see, hear and remember, do we have conscious, subjective feelings? And what things, besides human brains, are conscious? When we ask these questions, we crash into the solipsism problem. I can’t even be sure that you are conscious, so forget about determining whether bacteria, cuttlefish or smart phones have an inner life. That is sheer speculation, which cannot be empirically resolved. (See my 2017 post “Jellyfish, Sexbots and the Solipsism Problem.”)

As a result, theories of consciousness will always ask us to take a lot on faith. Like, Only we humans are conscious, and we’re a lot less conscious than we think we are. Or, Everything is conscious, including bed bugs, compact-disk players and even dark energy. We end up choosing one story over another for subjective reasons, because we find it beautiful or consoling, because it helps us make sense of our lives.

Morality, like consciousness, can be investigated empirically. Scientists such as evolutionary biologist Robert Trivers (whom I profile in Mind-Body Problems) have proposed theories about the origins of our moral instincts. Researchers can identify genes and neural activity associated with altruism and empathy, aggression and sociopathy. But scientists cannot tell us what is right and wrong. They cannot deduce ought from is.

You might think philosophers, who have a hard time competing with scientists in the realm of what is, have got a handle on what ought to be. But many philosophers have decided that “moral rule” is an oxymoron. There are exceptions to every ethical rule, even one as seemingly absolute as not killing kids, which my country does all too often. So forget getting definitive judgments on lying to a friend or cheating on your spouse.

Next up, the meaning of life. What is life’s purpose, its point? What makes you feel good, and helps you keep going when you feel bad? Here again, science can be helpful. Scientists can search for neural and genetic causes of negative and positive emotions, and they can test the efficacy of medications, psychotherapy, electromagnetic therapies, meditation, brain implants and other ways to improve mood.

But science cannot dictate what makes life worth living, and we answer that question in wildly disparate ways. You fantasize about spending a year on a silent retreat seeking enlightenment, or building an orphanage for kids with AIDS in Tanzania, or looking for genes that cause schizophrenia. I would rather work on a mega-merger that nets me $100 million, which I celebrate by partying with my pals on my 100-foot yacht. Nothing is more a matter of taste than the meaning of life.

Neuroscientist Christof Koch, Crick’s long-time collaborator (and another subject of my book), insists that the mind-body problem will yield an objective solution. He claims that soon researchers will construct a consciousness-meter, which renders judgments as objective as those of thermometers and barometers. The consciousness-meter would indicate whether a given thing is conscious, and how conscious it is.

But I doubt we will ever have a consciousness-meter that resolves consciousness-related arguments to everyone’s satisfaction. Scientists cannot build a consciousness-meter until they reach agreement on what physical conditions are necessary and sufficient to produce consciousness. And scientists cannot reach agreement on those conditions unless they have a means of solving the solipsism problem, that is, a consciousness-meter.

Even if we somehow invent such an instrument, we still won’t solve the mind-body problem, because we need more than an objective measure of consciousness. We need objective measures of goodness and meaningfulness, too. We need a morality-meter, and a meaning-meter. Let’s throw in a beauty-meter too, because aesthetic judgments also affect our choice of mind-body theories.

We will always have to rely on our flawed, subjective human judgments when we try to figure out who we really are and should be, as individuals and as a species. The lack of objective measures of consciousness, morality and meaning has a big upside. If we cannot discover a final, objectively true solution to the question of who we really are, we can keep exploring ourselves, imagining ourselves, inventing ourselves forever.

Further Reading:

Mind-Body Problems (free online edition)

Mind-Body Problems (abridged Kindle edition)

Mind–Body Problems: My Meta-Solution to the Mystery of Who We Really Are

Jellyfish, Sexbots and the Solipsism Problem

The Mind–Body Problem, Scientific Regress and "Woo"

Is Consciousness Real?

Can Integrated Information Theory Explain Consciousness?

Meta-post: Horgan Posts on Brain and Mind Science

See also “Mind-Body Problems and Psychedelic Tales,” my conversation on Meaningoflife.tv with Russian artist/writer Nikita Petrov.