Evolutionary Causation

Evolutionary Causation

Evolution is a causal process. But it is a causal process unlike any other. It is a causal process in which the effect vastly exceeds the cause, and indeed (in a loose sense) contradicts the cause. The most obvious point is that the effect is much more complex than the cause: from natural selection operating over simple entities, ever more complex entities evolve. At the origin of the causal chain leading to humans we have simple bacteria; and there is no infusion of complexity from outside, except that provided by genetic mutation and natural selection. The evolutionary causal process takes us from simplicity to complexity, dramatically so. Evolution also takes us from mindlessness to minds—from matter to consciousness. Nothing psychological directs the evolutionary process, but something psychological emerges from it. The effect is mind, but the cause is mindless. It is the same with purpose: there is no purpose to evolution by mutation and natural selection (despite the misleading connotations of that phrase), but the result is animals endowed with purpose. Teleology is caused by non-teleology; efficient causes produce final causes. Animals desire and intend things, but evolution does not. Similarly, animals—some of them—have foresight and plan ahead, avoiding future catastrophe; but evolution has no foresight and is not deterred by future catastrophe. Evolution could drive all animals to extinction and not lift a finger to avert that consequence—just as it has driven countless species extinct (nor does it lament those vanished species, as we might). Evolution is blind in its operations, but it produces animals that are not. Evolution is also amoral, wasteful, cruel, and indifferent; but it produces at least one species with a moral sense (and maybe more). Indeed, it produces moral beings that deplore the very process that led to them: we would change nature’s methods if we could. We recoil at the very process that leads to our ability to recoil. Our moral nature is not nature’s nature, but the opposite of it. Finally, evolution has no comprehension of anything–no understanding or intelligence or insight–yet it causes creatures that have comprehension of many things, including the evolutionary process and its lack of comprehension. Thus we can say that animals (especially humans) are caused by a process alien to themselves: animals have characteristics that are not found in their (remote) evolutionary causes, and which are at variance with their causes. The causality is a kind of paradoxical causality—as if it gives rise to things opposite to itself.

The same can be said of embryological causality, which is in many ways just like evolutionary causality. The embryological process takes us from the simple, mindless, purposeless, blind, amoral, and uncomprehending to the opposite of these traits—to a being with the negation of each of them. The process itself is one of mechanical self-assembly, guided by nothing, not even a blueprint, purely local in its methods of protein synthesis; yet it produces a being endowed with a rich set of traits. The causality is again paradoxical, anomalous, surprising, hard to believe, miraculous-seeming. It has the look of creating something from nothing. But it is entirely natural, governed by the laws of physics and chemistry, just like evolution.

No such paradoxical causality is assumed in creationist models of evolution or embryogenesis. According to those theories, the cause of creatures with the traits listed is another creature with the traits listed: God is precisely a being with complexity, mind, purpose, foresight, morals, and comprehension. Creationist causation is non-paradoxical (paradoxically!), since the cause has the very traits found in the effect. But that theory is known to be false, while evolution by natural selection is known to be true—so we are saddled with the kind of causation it involves. And notice that it is not just that the causation is emergent or generative; it actually involves negating the defining features of the cause—that is, producing traits that are at variance with the nature of the cause. It is just as if nature were contradicting herself.

It might be said that evolutionary (and embryological) causation is not as special as I am making out. Isn’t the early history of the universe likewise causally “peculiar”? After all, the universe was once all dispersed gas and only gradually did gravity create solid discrete bodies—stars, planets, galaxies, etc. Didn’t physical causality produce the solid and massive from the vaporous and weightless? Well, no, it didn’t, because all that gas was simply dispersed matter, with the standard properties of matter—mass, volume, electric charge, and gravity.[1] The universe never went from non-mass to mass or non-gravity to gravity. There was no paradoxical emergence, no something from nothing, just the working out of what already existed—basically, material aggregation by gravitational force. Even the production of the elements inside stars proceeded by the pre-existing laws (gravitational compression). It is only when we get to the evolution of life that the surprising kind of causality kicks in; then the universe discovers a new kind of causal process, with vastly greater generative power. Mutation and natural selection, genes and self-replication, prove to introduce a new kind of causation, capable of far more impressive feats than any observed hitherto—even if they are far more local and parochial, as well as less physically powerful (it takes only sunlight to fuel the whole process). The causation involved in the expanding universe operates on a much larger and more general scale than the expanding of life on earth, but it is far less impressive than evolutionary causation in its innovative power. The cause-effect mismatch of the latter is not mirrored in the former. Evolution is causally prodigious.

It would be good to have a label for the two types of causation, but none currently exists. We might borrow from Kant’s discussion of the analytic-synthetic distinction and press into service “ampliative” and “augmentative”. Thus non-evolutionary causation might be described as “ampliative causation” because it merely spells out what was already present: it adds nothing essentially new, though it can yield non-trivial transformations in the universe (stars, elements, black holes, etc). By contrast, we have “augmentative causation” in which radical innovations occur, even the kind of oppositions I have described. Evolution and embryogenesis involve augmentative causation—as a synthetic judgment for Kant involves going beyond the content of the subject in the predicate. Or we could speak of “conservative causation” versus “creative causation”, or “easy causation” versus “hard causation, or “mechanical causation” versus “innovative causation”. Of course, it might be maintained that the two types of causation really collapse into each other, because what I am calling a special type of causation really reduces to the other type. Either the evolved traits I listed do not really exist (“eliminativism”) or they can be reduced to properties that obey the ampliative type of causation (“reductionism”). I have not claimed to refute such a position here; my point has been that evolutionary causation is special on the assumption that the traits in question exist and cannot be reduced away to properties found in the evolutionary causes that don’t presuppose them. That is, I have assumed that mammals, for example, instantiate a range of traits not found in bacteria (mind, purpose, morals, etc). Given that, we need to recognize two basic kinds of causation in the universe (though they may be interwoven in complex ways).

I strongly suspect that this distinction lies behind an historical puzzle concerning the discovery of the theory of evolution (indeed I formulated the distinction while trying to solve that puzzle). It wasn’t until the nineteenth century that Darwin (as well as others) came up with the correct theory, though there was nothing to prevent earlier thinkers from discovering it, even going back to the ancient Greeks. The question was how to explain biological adaptation, and the answer is blindingly obvious once formulated; yet no one thought of it. It was quite possible to come up with the theory from the armchair by a priori reasoning, and it is not the kind of counterintuitive and difficult theory that (say) quantum theory and relativity theory are. All we need are the notions of chance variation and differential survival. The theory really could have been invented by Aristotle or Descartes well before Darwin’s time—so why wasn’t it? In fact, Darwin himself did not endorse it from the armchair but had to amass huge amounts of empirical data before he could accept the theory—the data forced the theory on him. Why the reluctance to accept what seems so blindingly obvious? (Selective breeding alone should have given the game away long before.) Something seems to have been blocking people from seeing it—and more than just piety and tradition.

My suggestion is that it was the nature of the causation involved that made the theory invisible for so long: people just assumed that the cause of animal (and human) existence had to conform to the usual kind of conservative ampliative causation. Hence the easy attraction of the creationist picture: it didn’t involve counterintuitive paradoxical-looking causation, but just regular causation in which cause and effect match each other. It turns out that this view of causation was too restrictive, as we now understand, but it is not surprising that there would be resistance to it at a gut level. The production of life had to be a causal process of some sort, but the kinds with which we are familiar respect the conservative principle, so it had to be that kind of causal process. We have certainly never observed the kind of creative causation manifest in the evolutionary process, simply because it takes place over such a long span of time. The idea that things like humans, with their distinctive traits, could be caused by a blind mechanical amoral process, originating in things like bacteria, was just too much of an affront to habitual assumptions about how causality works. And indeed it is still difficult to make sense of the causal process involved, precisely because it seems to entail getting something remarkable from nothing very much. It is thus very surprising that Darwin’s theory is true—something to marvel over (mind from mindlessness, morality from amorality). This explains why it was so hard for Darwin and others to recognize its truth. If someone had come up with the basic idea centuries earlier, it would have struck them as preposterous: how could chance variation in mindless entities, combined with blind natural selection, have caused the creatures we see today? We have found out, however, that the impossible is actually true—if I may exaggerate a bit. So it is not inexplicable that Darwin’s theory lay hidden for so long, despite its simplicity and a priori availability—unlike Newton’s theory that required enormous feats of mathematical reasoning and pure genius. No one came up with Darwin’s theory for so long because it seemed causally impossible—quite unlike the traditional creationist story (despite its falsity). Even today I suspect that many people resist Darwinism simply because of their habitual intuitions about causality, formed by ordinary observation, not because of any immovable religious commitment. People came round to the heliocentric hypothesis much more easily, because it did not challenge their intuitive notions of causality. But if what I am suggesting here is right, it is much harder to persuade people of evolution because of the causal picture it implies. To put it more positively, in order to overcome resistance we need to address ourselves directly to the question of causality and face it head on. The theory should be advertised as empirically correct but causally counterintuitive, or at least causally surprising. Simply passing over the causal question in silence, without facing it squarely, leaves people uneasy and perplexed. We need to accept that when species evolved a new species of causation evolved.[2]

[1] An exception might be made for the instant of the big bang in which it is said that matter, space, and time came to exist with extreme rapidity. Putting aside the question of whether that is the right thing to say, my comment is that if this is indeed so then causation at this early stage had the kind of innovative power I am attributing to evolutionary causation. Thereafter, however, physical causation followed a far more conservative trajectory.

[2] This is not to deny that evolutionary causation is grounded in ordinary physical causation (compare mental causation); it is just to say that the macro causal process of evolution involves the production of kinds of entities not present before. Teeming life comes from monotonous non-life—animals from atoms, men from molecules.