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Teleology Rises from the Grave
Stephen Asma says biology needs to understand the purpose – the ‘telos’ – of organisms and systems.
In 1790, in his Critique of Judgment, Immanuel Kant famously predicted that there would never be a “Newton for a blade of grass.” Biology, he thought, would never be unified and reduced down to a handful of mechanical laws, as in the case of physics. This, he argued, is because we cannot expunge teleology (goal-directedness), that is, the idea of purpose, from living systems. The question ‘What is it for?’ applies to living structures in a way that has no counterpart in physics.
Most Anglo-American philosophers, historians of science, and theologians have completely misunderstood his argument. Their usual narrative goes like this: Kant said there would be no Newton of biology; along comes Charles Darwin (1809-1882), the Newton of biology, who shows that natural selection explains adaptation without appeal to purpose; fast-forward to the present, and we are now the inheritors of a mechanical biology, and only religious cranks still bleat on about teleology. There it is, clear and simple. And wrong.
There are a few different teleology traditions, but the Anglo-American conversation has been blithely unaware of all but the dumbest and loudest version. This is the one which claims that adaptation in nature must be the result of a supreme Designer because chance alone cannot account for gills in water, lungs on land, complex eyes, cell flagella, etc, and that’s why a mechanical science will be incomplete. This, in a nutshell, is the natural theology [arguing for God from nature, Ed] tradition of teleology. It goes back to Plato’s Timaeus, but its heyday was in the eighteenth and early nineteenth centuries. Even Darwin, before he went on his famous voyage on the HMS Beagle, read and admired the natural theology of William Paley, who likened nature to an elegant watch. A system of parts that fit other parts precisely and has a function of telling time – a watch – presupposes a designing intelligence – a watchmaker.
Darwin killed the design argument. His theory of chance variation and natural selection drove a stake though its heart. Rather, the accumulation and spread of heritable traits by the mechanical operations of genes, proteins, geology, climate, and so on, slowly shape organisms to fit their environments, making them appear designed. In philosophical jargon, Darwin changed a priori design – God’s plan – into a posteriori adaptation. Excellent popular-science postmortems of natural theology include Richard Dawkins’ Blind Watchmaker, Daniel Dennett’s Darwin’s Dangerous Idea, and Jerry Coyne’s Why Evolution is True.
A very small but vocal minority never got the obituary notice. They never accepted that Darwin staked the heart of natural theology, and they carry on that tradition, calling it Intelligent Design (ID). Like Doctor Frankenstein, ID folks keep trying to stitch together a body out of the corpse of natural theology and revitalize it. Here’s the problem. Whenever anyone mentions the word ‘teleology’ or ‘purpose’ in biology, the Darwinian orthodoxy get out the pitchforks and chase the fiend down. Some concepts of teleology have nothing to do with religion; yet they get caught up and exterminated anyway in the confusion.
Other teleology traditions include (i) Aristotelian teleology, (ii) holism, (iii) unity of nature, (iv) conatus/vitalism, (v) autopoiesis, and various nuances within each category. The popular anthropomorphic tradition of natural theology gets mixed together with these other traditions. So, let’s sift them, and see if there’s anything there compatible with Darwinian naturalism.
Teleology Rising © Woodrow Cowher 2018. Please visit woodrawspictures.com
Aristotle saw goal-directedness in nature because natural processes always unfold toward some goal; acorns develop into oak trees. Also, parts of organisms are simultaneously for the sake of their wholes: bone tissue is for the sake of bone, blood is for the sake of circulation, and teeth are for the sake of chewing. Aristotle refers to these ends/goals as final causes, defining a final cause broadly as ‘the end, for the sake of which a thing is done.’
Aristotle’s teleology is difficult for us to appreciate because hundreds of years of Medieval theology misinterpreted it as saying God’s mind put the goals into nature. That was not Aristotle’s view, despite generations of Schoolmen who tried to ‘baptize’ him. Then after the scientific revolution, people came to think of nature as a giant machine, and like all machines the goals would need to be installed by some kind of designing mind. Again, this was not Aristotle’s view. Instead, he thought of teleology as a feature of nature in the same sort of way that we think of gravity: as an impersonal, undesigned, aspect of matter.
Aristotle was pretty critical of the simple versions of evolution that he saw in Empedocles and Democritus, because he thought that material bits could not clump together into sustainable organisms unless matter had the organism’s recipes built into nature, in terms of his final and formal causes. So Aristotle saw teleology as a way of describing the regularity of biological procreation, behavior and anatomy. If he had known about DNA, he probably would have slapped his forehead and said, “So, that’s how the information shapes matter!” But notice, we still have Aristotle’s final cause question: How does a common stuff (his was matter; ours is DNA, or stem cells) get differentiated into diverse organs and organisms? The DNA alone is not enough to explain this, and after we cracked the genome we realized that we needed to study development more carefully, so we’re finally discovering hox genes and epigenetic processes that regulate all that DNA potential into actual organs, structures and behaviors. Those regulatory causes only recently targeted by biologists were the aspects of life that Aristotle called ‘teleological’.
Unlike natural theology, Aristotle’s ‘methodological’ teleology is not incompatible with Darwinism. Aristotle just thought that you can’t do biology by talking only about whirling atoms; you also need to discover why this organ or behavior fits with the animal’s structure/function and environment. That question only reverts to divine psychology if you’re a natural theologian; but for both Aristotle and Darwin it reverted to the unique natural living conditions of the organism.
Setting aside his temporal teleology (acorns becoming oak trees), let’s concentrate on the holism tradition that Aristotle created. The holism tradition of teleology claims that biology cannot be reductionist but must instead recognize the causal relationships of cells inside tissues, inside organs, inside physio-systems, inside organisms, inside environments. The Medieval metaphysicians pursued this avenue, calling it mereology, the study of the relationships between parts and wholes, but they derailed the inquiry by trying to determine which of these nested levels was the true ‘essence’ of the thing. Eventually Anglo-American analytical philosophy became reinterested in holism in the twentieth century, but only as a logic problem. Continental philosophy, on the other hand, has had a longstanding obsession with biological holism. Goethe, Kant and Hegel were deeply interested in the way that biological form seemed to govern simpler physio-chemical processes, and they tried various ways of understanding the organization of nature without appeal to natural theology.
Why can’t biology succeed by dissecting everything down to chemistry? Because we often can’t understand a biochemical process without understanding what it’s for. We need to know what beneficial effects it has for the organism. No one in chemistry would claim that the carbon loses electrons ‘for the sake of’ becoming carbon dioxide; but in biology we have to acknowledge how (unless it’s a vestigial trait or a spandrel) a specific trait or behavior is for the survival of the organism or its population. So all the biochemical processes that result from breathing oxygen are a way of running an organism for fast chemical reactions in its cells. Sexual reproduction, for another example, also has advantageous selection effects, increasing offspring fitness through variation and hybrid vigor. This adaptive effect explains why the mutation of sexual reproduction was selected for and why it persists. It is a methodologically teleological explanation.
For holists, this attempt to find ‘the end, for the sake of which a thing is done’ applies to the structures as well as to the processes of biology. So a leaf is unintelligible without understanding something about trees, and hence the purpose of the leaf; a heart is incomprehensible without the circulation system; a brain makes little sense except in the body of a creature that can move, and on and on. Eventually these teleological wholes are referred to the ultimate purpose or goal, which Aristotle, sounding very Darwinian, describes as “the most natural of all the functions of living creatures, namely to make another thing like themselves.”
The holism school wants us to remember, amidst all the real successes of reductionistic science, the validity of higher levels of causation and explanation. Holism is a kind of causal pluralism, gently reminding the atomic and genetic determinists that organisms and ecologies are not just epiphenomena of these phenomena.
Real or Sham?
Teleological statements are explanatorily robust in biology, but are they real or sham explanations? Kant argued that reason cannot help but project purpose into biology, and we should accept modest teleological claims as ‘regulative principles’ of thought. By this logic, it’s scientifically respectable to claim that hollow bird bones are for the sake of flight. The mind can’t stop there, according to Kant, and naturally goes on to project a whole system of purposes into the biosphere. But it can quickly get silly: grass is for the sake of cows, cows are for the sake of human food, and so on… Like Voltaire in Candide lampooning the idea that “all is for the best in the best of all possible worlds,” Kant lampoons the hyperbolic teleologists who claim that mosquitos help humans wake up and stay active, and tapeworms must aid digestion for their victims. The trick in biology is to keep the local teleology, but throw out the global or cosmic stuff.
When we’re doing biology, Kant argued, we need to subordinate simple physics/chemistry explanations to functional teleological explanations. We need both levels of causation and explanation, and one level does not reduce to the other. Many biologists and philosophers, following Kant, have argued that we can pretend that things are for the sake of goals, but that this pretence is just methodologically helpful (‘instrumental’), and not referring to anything real. Can we, however, go beyond the purely instrumental justification to the kind of teleology that is an explanation of how things really are? Yes and no.
If a neuroscientist were to ask me why I do philosophy, I might say something like, “Certain neural pathways were sculpted in my developing brain, such that cingulate, prefrontal and parietal area activity easily trigger my hedonic dopamine system, causing me to like doing philosophy.” When my friend asks me why I do philosophy, I’m likely to say something like, “Solving conceptual puzzles and reflecting on profound stuff is deeply satisfying for me.” When the Dean of my college asks me the same question, I’m likely to trot out something like, “Philosophy improves critical thinking and shapes students into better citizens of our democracy.”
These explanations are not in competition with each other. One of these accounts is not the correct one, usurping the others, or reducing them to mere figments. They are all compatible, and they are all true. Likewise, if geneticists give a molecular account of human skin color differences, and evolutionary biologists give an adaptive account of skin color, they are not competing to be the correct explanation. Here are three different but compatible correct accounts of skin color:
(a) A purely mechanical account of small changes in the melanocortin 1 receptor gene (MC1R) tells us how melanin concentrations can produce darker or lighter skin.
(b) A person living in an intensely sun-soaked region will survive better if their skin is darker because carcinogenic UV-B radiation is blocked by increased melanin pigmentation.
(c) Around 1.2 million years ago, which is about 300,000 years after our ancestors lost their body hair, group migrations started new environmental selective pressures. Lighter skin evolved in less sunny regions, allowing necessary vitamin D production, and darker skin evolved in the populations of very sunny regions.
Notice that the first, biochemistry explanation, may work fine without teleology, but the other two, adaptive explanations, are strongly teleological – not in the sense that skin cells foresaw the goals eventually arrived at, but in the sense that the distribution and persistence of these phenotypes and their genes only make sense if they are ‘for the sake of’ survival (excepting the usual caveats about spandrels or founder effects).
The Unity of Nature
Kant recognized that the human mind can’t help projecting purpose into nature. But, contrary to many interpreters, this is not a free pass for Intelligent Design. Close study of his position reveals a nuanced alternative teleology. In addition to the instrumental teleology that seeks to link specific structures to functions (sharp teeth to carnivore diet, skin color to solar environment, sweat glands for thermoregulation, etc.), we must assume, he argues, a more universal teleology in all of nature in order to do science in the first place.
We need to tread carefully here because this issue is frequently misunderstood by both the foes and friends of teleology. The argument is: how could we expect nature to give us answers to our questions unless there was some rational or logical aspect in nature that could be interpreted by our rational minds? That is to say, science assumes some fit between our rational minds and nature’s structure, otherwise the former could not comprehend the latter. This ‘expectation of fit’ unifies all nature into a single domain of possible exploration. Kant further suggests that an encompassing ‘principle of purposiveness’ – an expectation that we’ll get answers to ‘what for?’ questions about the natural world – constitutes this unity of nature, and says “we must necessarily assume that there is such a unity without our comprehending it or being able to prove it.” (Critique of Judgment, Dover Publications translation, p.15).
This is a fascinating thesis, but almost everyone has made too much of it. This unity-of-nature assumption is necessary for us to continue doing science. But the theorem will always be vague, lacking in predictive power, incapable of proof, perhaps even incapable of true comprehension. In fact the most that Kant can say about the content of this assumption is, “There is in nature a subordination of genera and species comprehensible by us”, adding that there is “a harmony of nature with our cognitive faculty” (ibid, p.16). That’s it.
The important take-away from this unity-of-nature tradition is that it’s not really about nature. That’s its frustrating genius. For Kant, nature’s comprehendible structure is instead a function of our hardwired minds. If Kant’s right, then seeing nature as purposeful, at least to this extent, is built into our cognitive faculties.
Conatus & Vitalism
Baruch Spinoza (1632-1677) saw nature in fairly mechanical terms, but he recognized that living things do share a simple goal-oriented tendency; they strive to survive. He called this animating principle of living systems their conatus (‘striving’), and considered it the very essence of all creatures. It’s nothing like the teleology of the natural theologians, but it is a recognition that organic nature has an essential goal-directed imperative within it that cannot be captured by purely billiard-ball causality.
In the hands of some later theorists, the conatus became an occult metaphysical force. Following Blumenbach, Kant seemed to think that a ‘formative force’ (bildungstrieb) worked inside matter to cause the seeming miracles of animal reproduction. Many embryologists of the nineteenth century also assumed a vital (‘life’) force because they couldn’t imagine how an undifferentiated organic blob could slowly become an articulated fetus. Push-and-pull physics didn’t turn unstructured mush into highly structured working parts and integrated wholes, so the fetus was either fully articulated inside the mother and just grew larger with nutrition (preformationism), or it was an amorphous blob that sequentially took on form via a vital force (epigenesis).
The vitalist tradition was very popular, even after Darwin’s revolution. The idea of an occult invisible force that guides animal embryogenesis was congenial to solving the origin-of-life mystery too, and many used this deus ex machina to kill those two birds of the birth of life. Darwin tried a mechanical replacement for the vital force, but it couldn’t be corroborated. Famous embryologist Hans Driesch (1867-1941) even proffered an empirical vitalism, using the evidence that no matter how much he mutilated a developing vertebrate zygote, it still stayed on course, as if an invisible outside force guided the process.
Modern genetics and the science of stem cells have clarified the mystery of embryonic development for us, and occult embryology has rightly gone the way of phlogiston. However, the intuitive questions of the conatus/vitalism tradition are yet unanswered in modern biology, although some legitimate empirical work has emerged to better isolate the means of biological striving. For example, instead of thinking about conatus as a property of all living systems, neuroscientists today (like Jaak Panksepp) have discovered something like a brain-based ‘ conatus’ system in mammals: in the same way that all vertebrates possess a fear system, they also engage in seeking behavior – and recently neuroscience has isolated a foundational motivational drive that underlies diverse searching behaviors (hunting, foraging, procreation). In plain English, we call it desire. It is often classed with the emotions, but it is really a master emotion, a motivational system that organisms enlist in order to find and exploit resources in their environment. It energizes mammals to pursue pleasures or satisfactions, but it is not the same as pleasure. It is that growing, intense sensation of heightened attention and the increasing feeling of anticipation, as if you are just about to scratch a powerful itch.
Well before the Darwinian revolution people noticed the inexplicable weirdness of matter’s self-organization (autopoiesis). Yes, environmental conditions dispose of, or edit out, organisms and populations with deleterious traits, but do we need a better science of the step whereby these organisms come into being in the first place? From body plans to brains, matter crystalizes and canalizes into repeatable structures. Do we need a better science of form or self-organization itself to understand how this happens?
Many thinkers, like Darwin’s friend Richard Owen or the American naturalist Louis Agassiz, thought that the development and anatomy of animal form represented the incarnation of divine ideas in physical matter. The common vertebrate structure that we share with dogs and fish reveals, according to these thinkers, an archetype or leitmotif that God installs in nature. Then mutation and natural selection go to work to spin out biological variations on the theme. This unverifiable speculation is no longer a scientifically respectable position, but it remains a popular assumption for theistic evolutionists. Still, the question of organization has not fitted neatly into neo-Darwinism. Some smart twentieth century thinkers, such as Darcy Thompson, Stephen Jay Gould, Stuart Kauffman, and William Wimsatt, have suggested (and modeled) ways that material systems tend toward specific workable structures. There’s nothing occult about this. Instead it’s an attempt to articulate the logic or the mechanics of a middle level between genetics and organism selection. Kauffman, for example, has shown that systems of dynamic materials will coalesce around predictable states according to logical rules. He and others have suggested that some ‘self-organization science’ will need to join natural selection in giving us a more accurate understanding of the development of biological form. Like vitalism before it, some of this research seeks to address the development of complexity in animal embryology or in the origin of life. This ‘self-organization science’ tries to understand the way that micro processes are regulated by relative macro states over time, so it treads in means/end territory. It has become scientifically respectable by assuming a materialistic naturalism – everything occurs through physical processes – but it is nevertheless a recent descendent of an older teleological tradition.
My short history of alternative teleology traditions should help us recognize that biological goal-directedness is not dependent on mind, that is, on divine design or occult prescient forces. Following Kant’s ‘instrumental’ teleology, I have shown that one can be anti-reductionist about biology without nesting holism in mind. The order of both knowledge and the process is incorrectly reversed in such mind-dependent philosophy. So against the philosophers who think mind precedes biology, I submit that biological teleology actually precedes the sophisticated purposiveness of human consciousness. That is to say, the conscious mind emerges out of more primitive forms of biological conatus or seeking, not the other way around. And the biological goal-driven aspect of life is not a form of vitalism, but an accidental marriage of rudimentary nervous system, sensory-motor system, homeostasic systems in the organism, and ecologies of limited resource. Nor are these factors working to render the universe susceptible to the birth of consciousness, whatever that means.
Therefore there are perfectly legitimate forms of biological teleology that do not have conscious mind lurking behind them.
© Prof. Stephen T. Asma 2018
Stephen Asma is Professor of Philosophy and Distinguished Scholar at Columbia College Chicago. He works on the philosophy of the life sciences. His new book is Why We Need Religion (Oxford, 2018).