What are we to make of how much more fruitful science is when it’s applied to what’s purely physical than to what’s alive? That could persuade us that’s what’s purely physical and what’s alive are fundamentally different and we need to study what’s alive with something other than science. Let’s call that (methodological) dualism. Or it could tell us they operate on basically the same purely physical principles, what’s alive is just more complicated and returns results more slowly. Let’s call that reductionism.

How dry and remote that sounds! But for me it’s supremely important. That’s because it makes all the difference to something else that’s supremely important to me—the quality of my conscious experience. Think of consciousness as running on a platform. Choice between reductionism and dualism is choice of what software the platform runs on. Is it reductionist, or dualist?

I choose to believe I have that choice, and I choose to be a dualist. First, it lets me believe consciousness draws on processes not limited by the laws of physics. And, through coming to understand those processes better, that I can make my conscious experiences richer. For me that’s ultimate meaning—my conscious experiences being richer.

You may say, what matters more is what’s true and that’s reductionism. But is that truly what matters more? At the end of your life imagine looking back and reflecting, “What’s really mattered to me all along has been what I’ve been conscious of. If I’d believed I could make my conscious experiences richer, mightn’t I have looked for ways of doing so?”

That’s point one: one has the choice of believing in either dualism or reductionism, and the choice is significant and important, both for each individual and for the culture at large. Point two is, how can we make that choice? What concepts do we have available to help us?

It’s the argument that’s most often repeated that carries the most weight. That’s an argument for reductionism. It goes like this: if there were processes active in the universe that science couldn’t study or detect, it would have discovered them by now. In other words, lack of scientific evidence for those processes proves they don’t exist. It’s a notoriously weak argument but it makes intuitive sense. It can be harder to make sense of arguments for dualism.  Here’s an example: we create information. But we’re alive. Could information exist on a lifeless planet, like Mars? Information implies that something could be other than it is or could be made to become other than it’s otherwise bound to be. But in a reductionist world that isn’t possible. Put that another way: would it be possible in a reductionist world for two alternative possible outcomes for a future event to be conceived of, or does an ability to conceive of possible alternatives imply dualism? I think this is a powerful argument for dualism but it’s a squirmy kind of logic. Elsewhere on this site I’ve given other reasons for choosing dualism, I’m afraid they may appear to have a similar squirmy logic.

In this arena of vapid logics there sits an 800 pound gorilla, that fastens down the scales in favor of reductionism. That’s the mechanism Darwin proposed for evolution, natural selection, since extended by association with genetic mutation—the modern synthesis. This--today’s scientific mechanism of evolution--involves only purely physical processes. It’s hard to dispute that anything created entirely by a purely physical process is going to be purely physical too. We evolved therefore, this argument goes, we are purely physical. No dualism.

This blockbuster argument in favor of reductionism is seldom brought up in debates but looms implicit overhead. If even we, with our supposed minds, are products of a purely physical mechanism, what need is there for non-physical processes at all? With this blockbuster proof in favor of reductionism, why extend even a courtesy consideration to arguments for dualism?

This is made explicit in “The Science of Can and Can’t” by Chiara Marletto, a self-described radical reductionist: “the laws of physics… put formidable constraints on everything in our universe: on all that has occurred so far and all that will occur in the future… Their dominion extends even beyond what actually happens in the universe to encompass what can, and cannot, be made to happen” from page one. On page five she introduces living things, focusing particularly on what she says defines them, their genes, that she refers to as recipes. On page 9 she claims “It is now well understood how those have come about. Darwin’s theory of evolution explains how living entities and their stupendous biological adaptations… have come about in the absence of a designer, under no-design physical laws… What Darwin’s theory tells us is how the recipes coding for complex biological adaptations have come about without being explicitly designed. This will be key to understanding what the recipes are made of.”

Marletto’s goal is to shift the science world’s attention from what science has already discovered to what it hasn’t yet discovered, but could, what she refers to as counterfactuals. In other words, if there are things science can’t yet explain, we’re better off looking at what science hasn’t yet figured out, but could, rather than in new directions. It’s a bold new attempt to redefine the debate from the bottom up. In it, Marletto makes truth of Darwin’s theory the foundational argument for reductionism. Presented in these terms, if Darwin’s theory were to be abandoned, so would the primary argument for reductionism.

Turns out, the modern synthesis mechanism for evolution is not as decisive an argument as it is given credit for. At thethirdwayofevolution.com evolutionists as eminent as Denis Noble, James Shapiro and Eva Jablonska testify to their growing doubts about Darwinism. Darwin himself subtitled his “On the Origin of Species” with the more accurate “… the Preservation of Favoured Races.“ Essentially natural selection works by making yes-no decisions on instances of randomly occurring variations, with an efficiency of around 1% (according to Ronald Fisher). This mechanism can select among limited choices, such as alleles--alternative forms of existing genes--resulting in selection among races. But the creation of a new gene would require an almost infinite number of yes-no choices, for one out of 20 amino acids in as many of 500 positions along a protein for example, far beyond the capacity of yes-no choices in finite space and time. Making natural selection the deciding factor in whether to go with reductionism or dualism is a risky bet. If natural selection turns out not to be the primary mechanism of evolution, I think the loss to science would shift the debate in favor of dualism. Then the field’s wide open. That’s exciting. Counterfactuality, not so much.

Shaun Johnston
I think reductive physicalism "means" there is no mental entity, it doesn't "teach " us that, there is no proof of it except for absence of evidence. And agreed it cannot prevent us from happiness, because it's just as theory, not a real process. But our communicating to one another about experiencing happiness does seem to tell against it, telling us the mind can monitor what it going on in consciousness which I think physicalism denies.
Yoram Har-Lev
One can deny mental consciousness and still be happy
Reductive physicalism teaches us there is no mental entity and our conscious perceptions are illusions. It does not prevent us from happiness as we are good at activating our repression feature. See Reductive physicalism