In March of 2013, a lengthy article appeared in The Weekly Standard with the simple yet provocative title, “The Heretic.” The piece was accompanied by an ominous painting of a suited man, securely fastened to a stake above an encroaching fire. Encircling the ill-fated “heretic” are a horde of darkened, hooded figures. Some observe the execution with stoic reservation while others taunt the victim and revel at the violent spectacle.

The scene, which evokes cultural tropes of medieval inquisitions and their supposed anti-intellectualism, ironically depicts the academic barrage raised against famed atheist philosopher Thomas Nagel by his philosophical and scientific peers. According to the article, Nagel had been found guilty of the crime of challenging the reigning naturalistic paradigm, venturing even to publish his latest work, Mind and Cosmos, with the provocative subtitle Why the Materialist Neo-Darwinian Conception of Nature is Almost Certainly False.^[1] The work triggered a horde of scathing reviews from intellectuals like Steven Pinker, Daniel Dennett, and Jerry Coyne—the latter summarily dismissing Nagel as a mere “teleologist” and, consequently, “anti-science.”^[2]

One might suppose from this salvo of academic rancor that the subject of teleology remains taboo in academic circles. Nothing could be further from the truth. In fact, nearly a decade prior, Mark Perlman declared teleology to be the “hottest topic in philosophy of biology, psychology and mind.”^[3] Nagel’s crime, it seems, was to attribute to natural teleology anti-materialistic implications.^[4] Nevertheless, Nagel dared to believe that, like the prodigal son, teleology might return home and once again be welcomed into scientific discourse. In this second part of this series, I look at this reemergence of teleology, particularly in modern philosophy of biology and the role of adaptations and proper functions. As will become clear, the whole field of biology rests on fundamentally teleological assumptions—a portentous omen against naturalism’s claim of scientific preeminence. Life, it seems, is irreducibly teleological, and it will take more than the metaphorical burning of heretics to prevent the increasing tide of teleological realism from breaking the shores of academic discourse.

A New Hope

As Étienne Gilson observed in 1984, “Rare are those mechanists who admit that there may be teleology in nature.”^[5] Mark Perlman echoes this sentiment, stating, “By the twentieth century, analytic philosophers were positively allergic to any mention of teleology or teleological function.”^[6] Many, even within academia, still live under this impression, yet statistics speak another story. The intellectual tides have shifted, and, by one now slightly dated count, the topic consumes 10-14% of the discussion in several major contemporary works from related fields.^[7] For instance, Francisco Ayala, as early as 1970, argues, “Teleological explanations are appropriate and indispensable in biology, and… are fully compatible with causal accounts, although they cannot be reduced to nonteleological explanations without loss of explanatory content.”^[8]

More recently, the famed work of Chilean biologists Francisco Varela and Humberto Maturana lists autopoiesis as a clear manifestation of an organism’s teleological unity. Since the individual systems are dependent upon the unity of the network, the investigator must understand each system as operating toward a common end. In a cell, for instance, each system relies upon the other systems for the attainment of their goals. Unlike machines, each part receives its identity only in relation to the whole. Due to these implications, Varela himself has since become a teleological realist.^[9] Finally, Michael Tkacz has argued persuasively that optimality modeling, the most common method of determining adaptations in modern biology, provides a “particularly clear and evocative examples [of] research programs in which final cause plays an explicit unifying role in explanation.”^[10]

Nothing in biology makes sense except in the light of teleology.

Georg Toepfer

The list could be compiled endlessly. For instance, David Oderberg has written extensively on why the concepts “organism” and “species” are, themselves, teleological since each one is defined by the unity preserved by essential, goal-oriented traits of creatures.^[11] Georg Toepfer’s work has reached a nearly identical conclusion, leading to the provocative statement, “With this understanding of ‘teleology’ in mind, it becomes possible to modify Theodosius Dobzhansky’s famous dictum ‘nothing makes sense in biology except in the light of evolution’… to: ‘nothing in biology makes sense except in the light of teleology’.”^[12] This summary fails to even touch on the work by Andreas Wagner, Denis Walsch, Michael Hanby, and innumerable other philosophers and biologists who all seem to be arriving at the same conclusion: life is goal-directed.

The Naturalists Strike Back

Unsurprisingly, naturalists have not been silent against this onslaught of support for teleological realism. These “teleonaturalists,”^[13] as they have been called, have one common goal: demonstrate that biological teleology is nothing more than a useful fiction—a heuristic that can be dispensed with at any given time. Yet saying that one form of language is reducible to another is one thing; demonstrating this reduction is another entirely. There have been numerous attempts at just this sort of reduction (far more than can be covered in this short post), so I will limit myself to just two of the more prominent positions.

The most common stance by teleonaturalists has been labeled the etiological view, first proposed in analytic form independently by Ruth Millikan and Karen Neander.^[14] The success of the theory in winning converts was so total, it was viewed as a rare instance of a “philosophical result.”^[15] In short, the position maintains that a trait’s “proper function”^[16] denotes nothing more than that trait’s contribution toward the survival of a reproductively established family. Thus, functionality derives from the historical role the feature has played in the evolutionary history of a group.

This seemingly commonsensical view has, however, sustained a volley of lethal hits. For instance, Plantinga crafts multiple thought experiments in which what is normally considered malfunctioning organs provide a reproductive advantage. For instance, in a culture where crippled individuals are the only ones who are sexually selected, we would not conclude that being crippled was the proper function of legs. Likewise, Plantinga imagines a tyrannical, Nazi-like figure assuming power and reprogramming all non-Aryan subjects with a genetic malformation. When these subjects attempt to open their eyes, they experience severe pain, leaving them unable to perform normal life functions. All non-Aryans not displaying this gene are then systematically wiped out. Having allowed for their survival, would severe pain then become the proper function of eyes?^[17]

Robert Koons and Alexander Pruss have exercised similar logic in another direction. They imagine a world where all sick and dying creatures are taken by benevolent aliens to the “Great Grazing Ground” where they are revived and continue to thrive. In this world, no biological feature would have a proper function, since nothing would ever contribute to the survival of the organism. Wings would not have the function of flying since, no matter how well they operated, the organism bearing them would inevitably survive.^[18]

Elsewhere, Pruss argues that functionality should not depend on something extrinsic to the organism. If, for instance, curious aliens (he seems to have a liking for extraterrestrial thought experiments) kidnap all colorblind individuals and the earth subsequently experiences a mass extinction of humans, colorblindness would suddenly become the function of eyes. Proper functionality, he argues, should not depend on events causally unrelated to the organism.^[19] More objections have been raised by philosophers Jerry Fodor^[20] and Denis Walsch, leading the latter to declare, “The Etiological Theory of Function is less a triumph of philosophical analysis than a victim of it.”^[21]

Recognizing the shortcomings of the etiological perspective, John Bigelow and Robert Pargetter offered a revised account of biological functions which they call the “propensity theory.”^[22] Functions, they claim, ought to explain survival rather than survival explaining functions. Thus, they instead propose that functions derive from a subjunctive property of the features in question.^[23] If an attribute would confer survival value for a creature in its normal environment, the attribute can be said to function in that respect. In this way, the first arrival of the feature would have a function—a statement denied by the etiological perspective. Moreover, propensity theory would return to functions their explanatory power. Functions would account for the eventual survival of the feature. Thus, the propensity theory, they claim, avoids many of the pitfalls of the etiological view.

Bigelow and Pargetter are, however, open to possible objections to their offering. For instance, the proposal relies on the concept of a “normal” or “natural environment.”^[24] This concept is notoriously difficult to define or determine for individual species. However, they assure the reader that “this sort of variable parameter is a common feature of many useful scientific concepts.”^[25] Similarly, their proposal would lead to some counterintuitive conclusions. For instance, the function of hearts is to pump blood rather than to make audible thumping sounds, yet since the advent of advanced medical technology, these sounds can be used to detect abnormalities in the heart’s beating, thus conferring a survival advantage to the sound of heartbeats. One would have to conclude, then, that hearts can now be said to have two equal functions—pumping blood and making a thumping noise. Waving off these objections, they argue the justification for propensity theory outweighs the force of these counterexamples.^[26]

However, this second teleonaturalistic offering has its own brand of issues. Many of the thought experiments leveled against the etiological perspective would work equally well against the propensity theory. Another point of attack has been the aforementioned notion of “natural habitat.” If the propensity theory relies on a stable notion of a creature’s habitat, then it is sneaking historical factors into the model. A trait’s current context may not, in fact, be the “natural” habitat from which the trait arose. As Perlman notes, “Without a historical basis, it is hard to distinguish between cases where a trait is survival-enhancing yet now fatal in an unnatural habitat, or naturally lethal in a natural habitat.”^[27] Hence, the propensity offering has not truly cleansed itself of historical considerations. This would, perhaps, be a survivable objection. However, Koons and Pruss have added that the concept of a “normal environment” in Bigelow and Pargetter’s paper is viciously circular.^[28] A “normal environment” is defined as the location where the species’ organs function properly, yet, simultaneously, we are told proper functionality is defined by the creature’s normal habitat.

Moreover, Plantinga has added that, on occasion, a dysfunctional organ might aid in survival. If, for instance, a major artery was to have elastic holes in it, then a properly beating heart would lead to hemorrhaging and death. However, a heart that beats at a considerably slower rate would, in fact, allow the individual to survive.^[29] Foreseeing this objection, Bigelow and Pargetter briefly note that the definition of a “normal habitat” should be extended to include the normal bodily functions of the organism.^[30] While this reply cuts off one objection, it simultaneously creates another. Reparative systems, such as blood clotting, only function properly when bodily conditions are abnormal. Hence, these systems would, on this account, have no proper function.^[31]

The Return of the Theistic Argument?

These are only two of the more prominent theories currently on offer, yet the prospects for other, lesser-known alternatives looks equally bleak. Plantinga has therefore concluded, “The prospects for a naturalistic account of proper function look dim.”^[32] But what does all of this have to do with theism and atheism? Could not the intellectually honest atheist simply admit that lifeforms are teleological without committing herself to any further consequence? Ayala himself has made this claim, stating that one could adopt an Aristotelian approach, whereby teleology is regarded as immanent within creatures only. He writes, “According to Aristotle there is no intelligent maker of the world. The ends of things are not consciously intended.”^[33]

While Ayala must be commended for his biology, his philosophy is lacking at this point. While Ayala is certainly correct that Aristotle did not posit a “designer”, his teleological system nevertheless is grounded upon the Prime Mover (Aristotle’s “god”) as the principle of perfection that all creatures seek to imitate. Thus, any appeal to a supposed “Aristotelian” teleology fails to break free of theistic implications. In fact, it is difficult to discover any coherent teleological system that is not fundamentally grounded on theism. Even the aforementioned Nagel has been criticized for his failure to even engage Scholastic and Ancient accounts of teleology and their criticisms of a purely immanent teleology—ones that mirror his own offering.^[34]

All in all, it remains to be seen if it is even possible to account for teleology outside of a theistic foundation. Obviously, much more can be said in support of this, but given the length of this post so far, that will have to wait for another day. Nevertheless, it is fairly safe to conclude from this that if biology is truly teleological (as it seems it must be), theism appears to be the only coherent philosophical account of this feature currently on offer.

Footnotes