From an evolutionary point of view there is a continuous gradient of intelligence (in the larger sense of the term), from lower life forms with no intelligence at all to higher life forms that exhibit consciousness and mental states. Presumably this is quantitative and continuous, since animals with higher mental states evolved from beings with lower or no mental states.

For a materialist this isn't a problem, since mental states are in the same category as eyes or wings or whatever advanced anatomical provides and evolutionary advantage to the species.

On the other hand a dualist faces a problem, because they would have to explain at which point in the evolutionary process (or for that matter in the development of an embryo) does the ontologically distinct mental state appear.

For a dualist solution to the mind body problem to be compatible with the theory of evolution, it seems that a dualist has two options:

  • A) Assign mental states to all orders of life, and assert that even such creatures as amoebas and viruses have mental states.
  • B) Provide an explanation for how mental states suddenly start to appear at some level in the hierarchy of creatures equipped with neural tissue, and possibly explain where that level is (when we go from unicellular to multi-cellular creature? From invertebrates to vertebrates? From animals with asexual reproduction to animals with sexual reproduction? Is it restricted to mammals? Primates?)

My questions are:

  1. Are there any options for dualism to be compatible with the theory of evolution other than the two I mentioned?
  2. How have contemporary dualists dealt with evolution theory? Given the success of evolution as a theory, it seems to me that any serious dualist would have to address the evolution/dualism issue.
  3. Is dualism compatible with the theory of evolution at all? Both A and B seems far-fetched to me.
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    There is no such gradient in the evolution theory:"The discipline makes no general distinction between changes leading to populations of forms less complex or more complex than their ancestors, and in such terms the concept of a primitive species cannot be defined consistently." Animals with "higher" mental states do not necessarily evolve from animals with "lower" mental states. Evolutionary adaptation can just as easily proceed through "degradation" of intelligence, and everything else. en.wikipedia.org/wiki/Devolution_%28biology%29
    – Conifold
    Commented Jun 10, 2015 at 3:33
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    @Conifold There is a short humorous novel written by Kurt Vonnegut called "Galapagos" where the theme of the book is the devolution of mankind. Commented Jun 10, 2015 at 7:23
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    @Swami Vishwananda Even earlier H.G. Wells described "degenerated" Eloi in Time Machine. en.wikipedia.org/wiki/Eloi
    – Conifold
    Commented Jun 10, 2015 at 23:07
  • I'd agree that mind-body dualism is not compatible with evolutionary theory. There would no way for the desire to survive to have an effect on the behaviour of the organism. For all his reputation Descartes conjectured that they form a unity, and this would be a third term in the equation. Let's face it, the biologists have a long way to go to explain how wanting to survive can have an effect on our behaviour.
    – user20253
    Commented Aug 29, 2017 at 17:58

9 Answers 9


The "gradient of evolution" does not exist, biological evolution neither has to be monotone in "complexity", nor does it have to be continuous. "The idea... is based at least partly on the presumption that evolution" requires some sort of purposeful direction towards "increasing complexity". Modern evolutionary theory, beginning with Darwin at least, poses no such presumption and the concept of evolutionary change is independent of either any increase in complexity of organisms sharing a gene pool, or any decrease..." The issue survives the demise of its premise however, and gets even harder for a dualist under option B), because now evolution may at some point produce neural tissues that support mental states, then "degrade" them until they no longer support them, then "progress" them again, etc.

Fortunately for dualists, A) vs B) is a false dilemma, known colloquially as the chicken and the egg. Neither the chicken, nor the egg came first, and yet at some point in the past there were neither eggs, nor chickens. They co-evolved and differentiated through intermediate stages. Darwin already had to deal with these kinds of arguments, when opponents suggested that something as complex as the human eye "could not possibly" evolve through random mutations. Because separate parts could not serve any advantageous purpose without the whole already in place. Of course, just like the chicken and the egg, human eye did not evolve by parts. Now these arguments are unified under the term "irreducible complexity", which the eye, or the mental states, supposedly have.

But once the magic of "mental states", modeled on human ones, is dispelled the far fetched alternatives disappear, and a solution becomes obvious. It's not that mental states have to be assigned to all orders of life, it's that there is a long scale, at the top of which we clearly have mental states, and at the bottom we have something that can no longer be called "mental states". Here is a simple analogy, one-cell organisms clearly do not have a nervous system, some multi-cellular ones have nerve cells, but not a system, but even single cells have a capacity to "feel" their environment and react. All a dualist has to do (not that I find it attractive) is assign "something" to all life, or perhaps even to all matter, that in a very advanced form turns into "mental states". And postulate that "mental" evolution shadows biological one. Teilhard de Chardin does something like that in the The Phenomenon of Man, and he by the way is also sympathetic to the original premise that evolution leads to increasing complexity. His culminates in the "unification of consciousness", the so-called Omega Point.

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    I never said that evolution needs to be monotone. However, it seems to me almost trivial that it has to be continuous. Something like the eye or the wing of a bird cannot have just suddenly appeared over the course of a few generations. Between the human eye and the photosensitive cells of lower order creatures, there had to be intermediate stages. Regarding "All a dualist has to do (not that I find it attractive) is assign "something" to all life, or perhaps even to all matter, that in a very advanced forms turns into "mental states"." Isn't this just vitalism? Commented Jun 11, 2015 at 0:13
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    @Alexander S King "Vitalism is an obsolete scientific doctrine that "living organisms are fundamentally different from non-living entities", if anything this is anti-vitalism: everything is dualistic, living or non-living. Panpsychism would be closer, but without the traditional anthropocentric ideas about what "psyche" is supposed to be. One might even declare behavior of quantum particles "influenced" by the "something". The reason such things seem ostensibly far fetched is because of implicit self-projection that elevates "mental states" to something special, and then special to humans.
    – Conifold
    Commented Jun 11, 2015 at 2:36
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    @Alexander S King "Continuity" in evolution is understood as the absence of saltations (leaps) and catastrophes, so-called gradualism, "which holds that profound change is the cumulative product of slow but continuous processes". However, "Saltation was originally denied by the "modern synthesis" school of neo-Darwinism which favoured gradual evolution, but has since been accepted due to recent evidence in evolutionary biology." en.wikipedia.org/wiki/Saltation_%28biology%29#History Catastrophes also can happen and did happen, albeit rarely, e.g. mass extinctions.
    – Conifold
    Commented Jun 11, 2015 at 2:48
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    @AlexanderSKing: Evolution can be continuous, gradual, and it can be abrupt. With such a rich encoded control mechanism as we have, the genes (very discrete) and their environment (very continuous gradients of concentrations of this and that) it's not either-or, it's both. Worth noting that with high complexity, such as our genes and their expression, a small random change can (although it's unlikely, but can) have a large apparently very complex effects, by effectively activating a different set of well-functioning genetic sub-programs, so to speak. Read "A New Kind of Science". Be patient. Commented Jun 15, 2015 at 1:10

Options (A) and (B) exhaust the possibilities for question 1:


  • every living thing has a dual nature (A), or
  • only a proper subset of living things have a dual nature (B).

you could even generalize "living things" to "things" and you'd still have the same pair of possibilities.

For question 3 panpsychism seems compatible, the various creatures in evolutionary history had varying levels/qualities of consciousness, but all were, and are, conscious.

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    The assumption of hierarchy, and the assumption that all of a species or none of a species are mental in (B) surely means (A) and (B) do not exhaust the possibilities for question 1. Conifold takes out the first supposition below, and I take out the other one. Given that there are two additional answers not covered by the 'only' two options, I am not sure why this is still an answer folks vote for.
    – user9166
    Commented Aug 29, 2017 at 19:29

There is a theory, in neuroscientist David Eagleman's Incognito, which is not addressed to your question, but does provide an alternate solution to it.

If we envision matter as a receiver (like a radio receiver), and spirit as a broadcast (like radio waves), then if having a spirit (being able to receive the broadcast) is evolutionarily advantageous, it could be selected for in evolution.

Even outside the radio theory, a human being could be highly optimized for "housing" spirit, whatever that means. If spirit carries consciousness and/or morality along with it, it could provide a huge evolutionary advantage. This works best if there is a smooth continuum between having no spirit and having lots of spirit; but even if "has spirit" is a strict boolean condition, it's still conceivable it could have happened by accident, and then have been highly advantageous.


Dualism merely states that existence is fundamentally made of two forms of substance, typically named "matter" and "mind." Any theory with these two traits as the foundation of existence qualifies as dualism. Thus there are plenty of ways to define dualistic theories which are consistent with evolution.

One of the larger challenges I have found people have with such consistency is that evolution is a scientific theory, and science and measurement go hand in hand. However, measurement and mind go together like oil and water. Consider IQ tests, which are oft criticized as only recognizing one form of thinking, or MBTI, whose efficiency has been questioned because it lacks bimodal distributions which its typification entails. As a general rule, measuring mind has been fraught with difficulty for thousands of years. Accordingly, do not be surprised when it is difficult to measure the claims of a dualist theory. Half of what they define is the unmeasurable.

To give an example of such a theory that I find helpful for shaking up ideas, consider a worldview where anything can have intelligence, even rocks. All you need is for a mind to elect to bind itself to a material object. However, powerful minds tend to elect to bind (for some definition of "bind") themselves to material entities which have the capabilities to manifest their will. Thus there is a general pattern of the most capable material beings, H. sapiens, being imbued with the most powerful intelligences. However, every now and then an intelligence may choose to bind to a "lower" creature, such as a dog, resulting in above average animals.

Is this the "true" world view? I don't know. It's entirely possible it is, but its real purpose was to define a dualist worldview which is fun to explore. For example, artists often claim that the canvas or the materials "spoke to them," and such claims have a 1:1 corresponding behavior in this worldview. Drugs can "shake your mind loose of its material body," and many religious patterns map into it. It is decidedly unmeasurable, but it should be a good reference point for arguing that dualism and any scientific theory can be treated as compatible.

It also shows a third potential answer, as an alternative to A and B: C) the relationship between mind and evolution is one of a statistical correlation, and thus not fitting into any simple monotonic gradient.

  • a) did you mean two kinds of substances (by writing "two forms of matter")? there are other different kinds of dualism. b) property (rather than substance) dualists like chalmers would deny that either IQ tests or intelligence have anything to do with the dual nature of the mind - a robot may get a high IQ score. c) what do you mean by minds electing to bind to stuff making them "above average"? what does that even mean? can you add references to literature on that claim, and any of the other claims?
    – nir
    Commented Jun 15, 2015 at 3:08
  • out of curiosity, are you a reductionist or a dualist?
    – nir
    Commented Jun 15, 2015 at 3:09
  • a) I should have written that, corrected. b) As for the IQ test, the purpose of bringing it up was an example of "science and measurement go hand in hand." All too often anyone who suggests anything besides a physicalist reality is immediately subjected to demands of measurable differences, especially when tying things into scientific conepts. c) A superior mind binding to "lesser" body would resut in something which appears to be lesser, but for some reason seems smarter. The entire goal of that section was to give an example of an approach which did not fit into the A or B columns...
    – Cort Ammon
    Commented Jun 15, 2015 at 4:01
  • ... which had enough interesting points to be at least worth an exploration. You will note that I do not claim anywhere that this point of view is "right," merely "helpful for shaking up ideas." The worlview I showed is clearly not sufficient on its own, but I have found it helpful as a backdrop for adding one's own ideas.
    – Cort Ammon
    Commented Jun 15, 2015 at 4:04
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    @nir I recently learned of the possibility of non-dualist, non-reductionist positions: Emergentism and supervenience physicalism. Commented Jun 15, 2015 at 17:09

This is an answer to question one:

Are there any options for duality and evolution other than the ones I have mentioned?

Although evolution in the contemporary scientific project lacks 'purpose'; Aristotle when he discussed evolution in both Physics, and Metaphysics dismissed evolutionary theory as incomplete as he regarded this as a flaw; one can regard Hegels Philosophy as addressing this (in vague and crude terms) the universe attains increasing self-awareness. In this context, the 'gradient of evolution makes sense'.

Hegel answers the problem of duality here by taking it all the way back to the origin: where being and non-being are different but also identical.

The following is a discussion of 'evolution' of life in Aristotles Physics:

In section II.4: Is chance also a cause? some opinions on this:

Chance and spontaneity are also counted as causes...[but] some people claim that there is a determinate cause for everything which is said to be a cause or a spontaneous event.

Aristotle, in his discursive style, a precursor to the academic style today, introduces the possibility of chance being a cause; and he offers an example:

They say that the rotation is a spontaneous event - that the motion which separated things out and established the orderly nature of the world began spontaneously.

Compare this to the contemporary notion of the universe arising by a quantum fluctuation; a mechanism for said spontaneous event.


But this should occasion surprise: at the same time as holding nature or intelligence or something (ie something other than chance) responsible for the existence and generation of animals and plants - since things do not come from particular seeds by chance, but an olive-tree comes from one kind of seed and a man from another.

He considers this as not fact, as such; or beyond contesting; he introduces the possibility that chance plays a part during the life of natural kinds; and not at the beginning:

In section II.8. final causes are crucially important in nature

By the same token, if someone's grain is ruined on the threshing floor, this does not mean that the rain fell for the purpose of ruining the grain: it is just a coincidence. So what is wrong with the idea that the parts of natural things are like this as well?


Take teeth, for instance: what is wrong with the idea that the front teeth neccesarily come through sharp and suitable for biting, and the back teeth flat and good for crushing food?

This in contemporary language is called Lamarkism - a competing theory to Darwins at the time of Darwin; but he questions this theory which posits a purpose.

Why should there be purpose behind this? Why should it not just be an accident?

And what goes for teeth can go for other natural kinds.

And the same question could be asked about any other part of the body which seems to have some purpose. So, where every part turned out to be just as it would have been if it had some purpose, the creatures survived because, spontaneously, they happened to be put together in a useful way.

By chance, the animals form 'useful' ie fit, for a 'purpose', ie it's environment construed broadly; which they 'survived'.

But everything else has been destroyed and continues to be destroyed, as Empedocles says, of his 'cow-like creatures with the heads of men'.

And what has not survived, ie not 'fit' for 'survival' is (tautologically) destroyed; he implicitly ascribes the doctrine to Empedocles; he now introduces the notion of 'defect' of error, ie mutantcy

...In the beginning, then, any combination like those 'cow-like creatures' which were incapable of achieving some definite end, must have arisen because of some defect in their source

Consider the puzzle of the 'chicken and egg' - what came first, has a resolution given our knowledge of genetics. The chicken must develop true from the egg; thus it is in the egg or 'seed' that a 'defect' or error in the genetic code can occur; now consider that Aristotles says:

Beside seed must come first, creatures cannot just spring straight into existence

ie the fruit of the seed breeds true from the seed; hence mutantcy can only occur there, that is in the seed.

Finally after stating the evolutionary theory of Aristotle, he states:

It is ridiculous for people to deny that there is purpose if they cannot see the agent of change without any planning...

So he re-opens the question of purpose after first critically evaluating the 'Lamarkian' theory which posits a purpose in a certain sense; and then positing a 'Darwinian' type theory which demolishes said purpose through selection and survival of the fittest.

  • Were Aristotle and Hegel discussing the evolution of species as understood in the context of Darwin? That's what I am asking about. My understanding was that Hegel at least was talking about a more general form of historical/social progression, not the specific evolution of biological species. Commented Jun 15, 2015 at 1:30
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    I've expanded my answer to show how Aristotle takes evolution into account, in the Darwinian sense; I'd suggest that Hegel considered as a progression of social/historical phenomena is a reading by the left/right Hegelians, rather than Hegel himself - who is closer to Neo-platonists tradition. Commented Jun 17, 2015 at 21:36
  • Thanks. New question. Given this discussion by Aristotle, why was Darwin considered such a shock in his time? Most of the ground seems to already have been laid for his theory. He just tied the knots. Commented Jun 18, 2015 at 1:20
  • @king: good question - it might be worth asking the question as new question as we're expected to keep discussion in comments to a minimum...or take it to chat, unfortunately chat doesn't appear on my mobile. Commented Jun 18, 2015 at 12:19
  • His main achievement as far as I recall is that he provided the evidence to back the theory up ie his expeditions to the Galapogos Islands and the studies of finches; still Aristotle was well known as a naturalist; and I'd speculate that he had observational evidence. Commented Jun 18, 2015 at 22:07

Our culture's favorite dualist, Descartes, mediates your two options for an answer to question 1 with the 'pineal gland' theory.

Minds are not necessarily connected to bodies. We need to account for the souls of the dead. But minds find an attraction to mechanisms in the material world that convey their intentions. So the brain, or some specific part of it, is a sort of hook that binds a mind to a body and provides control over that body by the mind. (His proposal for the physical manifestation of the hook was not the whole brain, but the pineal gland at the center of the brain. DMT aficionados agree, on the basis of visionary consultations with "See Urchins", but almost everyone else finds this silly.)

Descartes assumes that with the hook left unoccupied, the body would be inert. But we do not have to assume this, and later Cartesians have played with the idea. Hooks might be attractive to minds, but that does not imply that every hook will necessarily be occupied, or that animation implies thought. There might, in fact, be "philosophical zombies".

Forking from there, in a reincarnationist direction, not only human brains might present hooks. Animals might present more or less effective hooks at different levels of intellectual capacity with the clarity of the reception and the nature of the control afforded varying up and down the scale of intelligence. Of course, presenting a good hook, if it provides you with a whole new dimension of information which you can use to survive, would be an evolutionary advantage.

If you adopt this kind of casually decoupled dualism, where the two worlds interact opportunistically rather than at an essential level, there is no conflict between the idea that intelligence, which evolves, and consciousness, which should remain immune to material manipulation, are not necessarily the same thing. Intelligence may be a sort of behavioral wrapper around a hard core of ideal mind, fitting more or less closely according to its material construction. And the wrapper might sometimes, or even most of the time, exist without its core.

(At its wacky extreme, this gives rise to a sort of Gnostic Calvinism in some varieties of Witchcraft, where the humans that are not attuned to the NeoPlatonic realm are just animals, unchosen by God. I find it hilarious that the new religions just recreate the old.)


Karl Popper, and John Eccles, in The Self and Its Brain, outline an evolutionarily compatible model for dualism.

Popper identifies the evolutionary advantage of consciousness with the ability to mediate between world 1, -- matter, and world 3, ideas. Being able to form a hypothesis, then test it in virtual space, rather than risking life and pseudopod in the experiment, is a huge evolutionary advantage. He postulates that it could have developed in bacteria, producing the full continuum of your option A. Or could have emerged later in life's development, correlated with large neurostructres, and thus option B. Popper leans toward A. He identifies intentional behavior, hypothesis forming, and learning, in single celled creatures.

You dismiss the continuum of life model for consciousness. But Popper is not the only researcher who sees consciousness in all of life. Nicholas Humphreys, in Seing Red, spells out in detail how he thinks single celled creatures developed consciousness. Lynn Margulis also considers bacteria to be conscious. These other two are not dualists, but that is irrelevant to the point.


From a materialist point of view, I'm made of exactly the same things, quarks and leptons, as the mug on my desk. The proportions and configurations and numbers differ, but not the basic building blocks. There is not a shred of evidence that my body contains something physically different. Yet one of those combinations of quarks and leptons has mental states, and one, as far as I can tell, doesn't.

You also mention the progression from egg and sperm, which seem unlikely to themselves have mental states, to an adult human.

Therefore, evolution has nothing to do with this. We have progressions of configurations of the same stuff, whatever that is, in which one end has mental states and the other end doesn't appear to be.

We can have materialism or panpsychism, which are nice easy explanations. We also can hypothesize that some configurations of matter can match up with mind and some can't. We can make an analogy from software: the mug on my desk can't run programs, while my phone can, and they're fundamentally the same sort of stuff.

It isn't necessary for dualists to specify exactly where mind (or whatever) can join up with matter. Like many things, we can tell what's at one end or the other, but we can't pick out a good dividing line.


Just an idea : Another way to deal with dualism and evolution may be to see evolution as a dualism itself. Indeed, if you accept evolution, you already accept a naturalized dualism : You accepted the fact that a form of matter evolves differently than the rest of the universe. Only living matter is sensitive/able to natural selection. We are witnessing here a naturalized dualism, where both sides of the dualism is called nature.

A (Assign mental states to all orders of life, and assert that even such creatures as amoebas and viruses have mental states.)

would become

A' (Assign mental states to all orders of life, and assert that even such creatures as amoebas and viruses is mental states.)

In other words, mental state is somewhat not a dualism but more a simple reading of our materialist dualist condition.

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