Philosophy and politics in Gould and Lewontin's Spandrels.

§1 – The Spandrels paper.

The Spandrels of San Marco and the Panglossian paradigm: a critique of the adaptationist programme (or the Spandrels paper) is an exceptional case of polemic scientific literature. Written in 1979 by paleontologist Stephen Jay Gould and population geneticist Richard C Lewontin, it is considered a milestone of evolutionary biology. Its impact upon scientific practice sparked 40 years worth of debate and research. Its legacy covers seemingly disparate topics: from methodological questions, onto more philosophical problems, such as that of biological units, or the relationship between biology and politics.

In this paper I will provide an analysis of the Spandrels case, particularly emphasizing how Gould and Lewontin’s critique of the adaptationist programme was not, so to say, merely about arthropod paedomorphism or the color of snail-shells.

As widely known, the Spandrels paper is constituted both by a pars destruens and a pars costruens. In this first preliminary chapter, I shall provide a critical summary of both parts.

Pars destruens.

The essential thesis of the adaptationist programme can be summarized like this: the direct production of adaptation by means of natural selection is the primary cause of nearly all organic forms, functions, and behaviours.¹

Gould and Lewontin's critique of adaptationism works on multiple levels. Its caricatural depiction as « Panglossian paradigm » reasons that two main elements are to be criticized: 1) the adaptationist tendency to conflate the current utility of a trait and the reasons of its existence; 2) the adaptationist tendency to tell “just so stories”² to explain every biological trait through the same criteria – with the same of kind of (tautologically) adaptationist answer: « trait x exists because the organism needs it to survive ».

This criticism is not merely over research questions and methods – that, as long as we ask “adaptive questions”, we will only be able to provide “adaptive answers”. Such scientific practice would imply a specific epistemological position about biology itself. For the adaptationists, the only criterion to assess a biological truth seems to be its consistency with natural selection. As a result, « the criteria for acceptance of a story are so loose that many pass without proper confirmation »³.

As natural selection is considered as the only real principle guiding evolution⁴, adaptationism may be thought of as a form of panselectionism: everything is selected. Particularly, adaptationists submit every trait of an organism to its own adaptive story, reducing the relationship between traits in an organism to a matter of competition and selection. The explanandum necessarily undergoes a process of preliminary atomization. Every single trait is considered as an independent « structure […] optimally designed by natural selection for [its] function »⁵. When they fail to show an explicit part-by-part optimization of traits, adaptationists will resort to the notion of trade-off. Evolution is now a matter of compromise between parts, of which one can be optimized only at the expenses of others.

The problem of atomization is the ontological problem addressed in the paper. Considering organisms as mere « collections of discrete objects »⁶ involves at least three crucial problems.

1. In reducing the organism to a bundle of discrete properties, we may fail to see the nature of the relationship between those very properties. Moreover, there's no guarantee that the identification of a trait isn't arbitrary – what if, for example, because of this a priori atomization we failed to see that seemingly unrelated traits actually evolved together?

2. Atomizing an organism into traits in order to explain its current form by means of providing an adaptive story for each trait implies that the real subject of selection and evolution is neither the organism, nor the population or even the species. What is selected, and what ultimately evolves, is the trait itself.

3. We risk missing a crucial aspect of biological phenomena, their historical dimension. It is unlikely that we could explain the current state of Europe if we atomized the evolutionary histories of each nation. For this same reason, it is hard to see how biology can provide a deeper understanding of the evolutionary history of life, if all that is dealt with is unrelated and atomized “traits” and “qualities”, whose organization (the organism) is considered accidental at best, or as a mere epiphenomenon at worst.

Pars costruens.

Gould and Lewontin's proposal is best exemplified by the very term « spandrel ». Spandrels are by-products of strictly constraining previous architectural decisions (such as mounting a dome on four arches). Although the architectonic precision of the spandrel metaphor was discussed thoroughly, criticized (i.e. by Daniel Dennett⁷) and defended by Gould himself⁸, I think that we can dismiss this problem as essentially an end unto itself (or at best, a matter of literary efficacy rather than scientific precision). What interests us is the function for which Gould and Lewontin used the notion of spandrel.

Gould and Lewontin's view of life is essentially an architectural one. Naturally, they do not refute the notion of adaptation. The cases brought in chapter 5, A partial typology of alternatives to the adaptationist programme, are not to be thought as non-adaptive stories tout court; rather, the notion of adaptation is reinterpreted to fit a more organic and integrated view of the organism. According to Gould and Lewontin, an organism has got a Bauplan, a body-plan. « [T]he adaptationist programme (atomization plus optimizing selection of parts) can['t] do much to explain Baupläne and the transition between them »⁹. The body plan of an organism is

« so integrated and so replete with constraints upon adaptation […] that conventional styles of selective arguments can explain little of interest about them »¹⁰.

Natural selection is thus reduced to the function of mediation – ultimately, it is the body-plan that, playing the role of architectural constraint, determines how the species can and cannot evolve, what trait an organism can and cannot have. In this sense:

« constraints restrict possible paths and modes of change so strongly that constraint themselves become much the most interesting aspect of evolution »¹¹.

Not only Gould and Lewontin aim at shiftin the attention from the selective process of single traits to the very evolutionary history of the whole body-plan. The very status of natural selection (not the magnitude of its influence!) changes, becoming our means to explain the distribution of certain traits rather than the their form.

Constraints, on their part, can be of phyletic or developmental nature.

1. Phyletic constraints are the result of the whole evolutionary heritage of taxon – we share these constraints with our evolutionary relatives, be they other primates or other mammals or tetrapods. Basic general features of our body plan are usually the most ancient and the most silently constraining.

2. Developmental constraints are a subcategory of phyletic ones. One example is that provided by embryology. Early stages of ontogenesis, such as the embryonal states, are extremely refractary to change, as they constitute the most delicate moment of the formation of an individual. A change in the most basic structure is very likely to be fatal, and therefore extremely non adaptive.

According to Gould and Lewontin, th power excerted by such constraints grants that the organisms “interface” with natural selection as integrated wholes. In this sense, they can't be theoretically atomized and pulled apart into traits because natural selection itself cannot do it. Every change of the Bauplan is an alteration of the developmental programme – in other words, of the ontogenesis itself.

One of the attempts of Gould and Lewontin was to reintroduce the organism, in its own ontogenesis, into biology. According to biologists such as Pigliucci and Kaplan or Nielsen, they succeeded in it.¹² But this is only one of the themes that Gould and Lewontin considered so crucial to deal with. As their attack on adaptationism is carried out on multiple levels, so does the adaptationist counter-attack. By looking at the clash between positions, we can infer what nerve Gould and Lewontin may have hit.

§2 – « Postmodern neomarxism » haunts sociobiologists.

Almost 20 years after the publishing of the Spandrels paper, Gould published The exaptive excellence of spandrels as a term and prototype in defence of the notion of « spandrel », and therefore, as we have seen, of the architectural vision of life it entails. In this article Gould notices how their paper elicited reactions from any possible field. Some of them were of « puerile, “ain’t-I-clever,” sort »¹³. Despite their weak theoretical criticisms, the political character of their provocation makes them interesting, and that is why we are going to review them first. However, other critical approaches are possible, as some articles written in the last 20 years will show us. They will offer us the opportunity to delve deeper into the theoretical problems addressed by Gould and Lewontin and better see the real scope of Spandrels.

The first article, written by Gerald Borgia in 1994, is called The scandals of San Marco. The article straight up concludes that « Political bias remains as the only plausible explanation for Gould's attacks on adaptationism and sociobiology »¹⁴. According to Borgia, the critiques proposed by Gould (whom, incidentally, is the main target of almost all these counter-attacks) are so inherently flawed that they cannot be considered as the true message of the paper: Gould is said to have tried, in an act of supreme intellectual dishonesty, to push his political agenda through the appearence of scientific argument.

Borgia's criticism concerns mainly two themes: the “unscientificity” of Spandrels, and a defence of sociobiology. First of all, Gould and Lewontin are said to be inflating the problem that they declare to address. The examples brought against the adaptationist fashion of argument¹⁵ are biasedly cherry-picked cases of bad science, unrapresentative of the actual work of biologists and sociobiologists. According to Borgia:

« concerns about reductionism in Spandrels are severely overplayed and […] typically researchers attempt to test all reasonable hypotheses, although tests of nonfunctional ones are not always possible »¹⁶.

Notice however how this very criticism confirms Gould and Lewontin's thesis that adaptationists will acknowledge and then immediately downplay other non-adaptive hypotheses!¹⁷ Also, as we will see later, it is not true that non-adaptive hypotheses are refractary to empirical test.

Criticizing the alleged political agenda of Spandrels, Borgia interprets Gould and Lewontin's criticism of adaptationism and sociobiology as a critique of anti-marxism in biology:

« Gould and Lewontin's view, articulated elsewhere, that the sanctioning of determinisms by biologists, especially predictions about genetically selfish behavior from evolutionary models, presages political repression and frustrates the creation of a benign Marxist society »¹⁸.

There are two problems here though. First of all, the architectural view of the organism does not necessarily lead to a less violent natural selection in the reign of life – on the contrary, it makes radical change even more difficult to occur! Second, even if it was the case that Gould (mainly) and Lewontin had strong political ideas – if they articulated them « elsewhere », why should one focus on the Spandrels paper to criticize their conflation of biology and politics?

We come now to the second article, written by David C. Queller in 1995: The spaniels of St. Marx and the Panglossian paradox: a critique of a rhetorical approach. Letting aside the provocations¹⁹ and the attempt at downplaying the curbing effect of Spandrels on adaptationist extremism – such an effect is today still acknowledged and desired²⁰ –, I would like to draw the attention to Queller's criticism of « the Bauplan approach from continental Europe »²¹. While he admits that more attention was indeed given to non-adaptationists hypotheses, he notices that the Bauplan approach does not seem to have produced that same richness of knowledge as the adaptationist one. Apparently, most of the citations of Spandrels in the 20 years after its publication come in paper that show that « nonadaptationist alternatives offered by Gould and Lewontin [...] do not work for their particular case » and that then « settle on an adaptationist explanation »²².

The peak of the article, however, has a strongly political flavour. Speaking of what he calls « So-Just Stories » (discrediting a scientific hypothesis on the basis of its possible moral implications), Qualler says that his

« personal favorite is "How the sociobiologist got his spots." It tells us that sociobiologists read their brutish, capitalist, male-dominated culture into their biology, and then use this debased biology to justify the culture (this is a version of an old tale dating to Marx, who put the spots on Darwin) ».

It's hard not to believe such so-just stories when we think of, for example, Geoffrey Miller's infamous « Men write more books »²³. However, Queller's approach seems to be reasonable – after all, he says, sociobiology can emphasize altruistic behaviour, or the role of females etc., like his own work on social insects does. On the other hand, as we have noted before, Gould's emphasis on contraints could suggest conservatives undertones. Both approaches can bear whatever political implication; therefore, a “political critique” of sociobiology is practically baseless.

This emphasis on the political purity of sociobiology begs the question: do we find any reference to sociobiology in Spandrels? We do, but it does not seem to involve any politics. In the context of the decoupling of selection and adaptation, Gould considers cultural evolution a « “heritable” form of non-Darwinian [non selectionist] adaptation in humans »²⁴ and affirms that « Much confused thinking in human sociobiology arises from a failure to distinguish this mode from Darwinian adaptation based on genetic variation »²⁵. Sociobiology is here criticized only as a form of gene-reductionism – there does not seem to be any trace of politics here. Then, to put it rhetorically, why does Queller feel the need to call « St. Marx » into question?

§3 – Atomization and trait-delimitation.

As we have seen, Gould and Lewontin's main and original theoretical proposal was that of an architectural view of life. Such view entails a number of features, such as the emphasis on the integration of the organism as a whole or on the importance of development, and problems, such as the status of the trait or the method of studying integrated wholes.

Twenty years ago Massimo Pigliucci and Jonathan Kaplan wrote:

« Since the publication of the Spandrels paper, theoretical evolutionary biology has made several advances that have helped researchers to question a purely adaptationist approach to the study of phenotypic evolution. In particular, the role of constraints, tradeoffs and costs in evolution has been widely discussed and generally acknowledged. […] [G]enetic and developmental (sometimes referred to as epigenetic) constraints are a reality, and can be both measured in practice and accounted for in theory »²⁶.

Although science may not speak Gould and Lewontin's language of constraints, it seems to have elevated the theoretical gains of Spandrels to a higher level of rigor: if all constraints « can be considered genetic or epigenetic in nature »²⁷, then the integratedness of the organism does not

impede an analytical approach to it.

Ecologist Jeremy Fox and evolutionary biologist Mark E. Olson have raised the issue of atomization from both the epistemological and the ontological point of view.

In Why “The Spandrels of San Marco” isn't a good paper (2011) Fox writes « We can't do without atomization; the phenotype of an organism is too complex to summarize in one number »²⁸. Being science a matter of compromise between theory and heuristics, the re-integration of traits (possible i.e. thanks to « correlation matrices »²⁹) has to be preceeded by an atomizing analysis.

It is not just a matter of method though: « Nor can natural selection make due without atomization »³⁰. Where Pigliucci and Kaplan ask: « Even though constraints exist, is it possible to somehow ‘break’ them? »³¹, Fox replies:

« Lewontin himself once pointed out that an organism that wasn't atomized into independent traits almost certainly couldn't evolve by natural selection, because beneficial mutations would be all but impossible (any mutation would almost certainly just lead to a non-viable organism) »³².

So, even though natural selection only sees the whole of the organism, and therefore its relative fitness (that's why we can discard the discourse of optimization, and opt for « a model of survival of the barely tolerable », which emphasizes the role of eniromental and developmental constraints as a « limitation to adaptive evolution »³³), this whole should not be thought of as a homogenous object. Rather, even if there was such a thing as a body-plan, it would not necessarily deny the evolutionary autonomy of certain traits: a certain degree of atomization makes room for change. Moreover, according to Fox, if constraints were the real protagonists of evolution as Gould and Lewontin suggest, and therefore if the whole had a ontological primacy on the parts subject to natural selection, there could not be complex organs and organisms at all.

Perhaps constraints and natural selection should be thought not as mutually exclusive forces, but as in a feedback loop relationship. Take the case of developmental constraints. Only a complex structure whose change is “risky” can exert a limiting action on evolution; at the same time, complexity (which does not necessarily mean more integration) affects phenotypical expression, and therefore determines the organism's fitness. Gould and Lewontin are harshy criticized for not addressing the relationship between natural selection and constraints.

Fox concludes his article attributing much of the merit of today's scientific rigor not to Spandrels, but to the mere technological advancement (es. cheap gene sequencing) and to the mathematiciziation of both evolutionary and developmental biology. He refers here to Pigliucci and Kaplan, who notice how much of our knowledge about the actual integration between traits would be impossible without mathematical models.³⁴ One paradigmatic case is Lande and Arnold's method of measurement of selection on correlated characters (proposed in 1983 and considerably improved in the following decades). Natural selection can exert an indirect pressure on traits correlated with directly selected ones. Given a trait, the other ones can be thought of as its “environment” – if the internal environment changes (because of selection), it exerts a selective pressure on the trait. Taking into account such correlations makes it harder to make up just-so stories and curbs radical atomization, whitout reducing natural selection to a mere mediator. According to Fox, there's no reason « why a "non-atomizing" approach to understanding organismal form and function couldn't be thoroughly adaptationist »³⁵.

Olson devles deeper into these questions in his recent article Spandrels and trait delimitation: No such thing as “architectural constraint” (2019). He interprets the problem of the organism in terms of externalism/internalism dichotomy: either the organism is « passive and endlessly malleable […] molded for all practical purposes by selective forces external to developing individuals »³⁶, or the « interactions between parts in developmental systems so bias the morphologies that can be produced that these factors are the decisive ones molding organismal trait distributions »³⁷. We recognize this dichotomy as the main querelle animating Gould and Lewontin's proposal. According to Olson, Spandrels' legacy of refelections and criticisms about the notion of « constraint » allowed scientisits to overcome this dichotomy. Today biology speaks of « phylogenetic, developmental, genetic, and even selective constraints »³⁸. Infact, Olson reports that not only no biologist seem to mistake spandrels for adaptations, but that spandrels are not even things or parts of the organism in themselves. In doing so, he denies the epistemological and the ontological status of spandrels. This leaves us with a new, more interesting, problem.

First of all, we should notice that for Olson the « thingness » of a part of an organism is determined by its interface with natural selection – if it does not affect fitness, can we even say that it is a part of the organism? In this sense, Olson radically refutes Gould's notion of spandrel as « any geometric configuration of space inevitably left over as a consequence of other architectural decisions »³⁹: if it is just a « left over », then it is nothing at all. At the same time, he is careful not to deny the status of exaptations: « a “spandrel” can be an exaptation, but an exaptation is not necessarily a spandrel »⁴⁰. (This means that, almost paradoxically, a spandrel is a thing only in those cases when a left over is retroactively identified through functional cooptation and turned into a trait affecting the fitness of the whole!)

Real parts are therefore adaptations. The problem of organical integration can be decoupled from that of architecture and spandrels.

« Biologists routinely speak of “parts” of organisms as adaptations […]. This talk goes hand in hand with talk of a part being “an” adaptation. This language invokes the idea that an organismal trait is an identifiable entity in nature […]. If “parts” can be adaptations, then the part must be able to respond to natural selection to an extent autonomously from the rest of the body […]. This partial evolutionary autonomy is what Lewontin termed quasi-independence […]. »⁴¹

Although critical of Gould and Lewontin's paper, Lewontin's notion of quasi-indipendence is Olson's interpretative key. Quasi-indipendence allows us to account for the great variety of traits within the same species (or in phyletic group). Biodiversity is possible only if the same structure (the same body plan) allows a great variety of change within the same phenotypic space, be it of genetic (therefore leading to speciation) or epigenetic character.⁴² In Olson's words, « It is this developmental quasi-independence that seems to justify the atomization of organisms in studies of adaptation »⁴³.

Quasi-indipendence allows us to look at the developmental program both as a constraint and as a opportunity for « freedom » of expression. For example, of course birds will need a complex integrated apparatus to fly (it will need not only wings, but also a light skeleton, proper respiratory and circulatory systems and so on), but relatively autonomouos variations of certain traits will result in, for example, different styles of flying, which clearly affect an animal's fitness for their environment.

According to Olson, so called « spandrels » hardly are quasi-indipendent trait, as (given the literature of examples, which is mostly composed of « misapplied synonyms for exaptation »⁴⁴) none of them can respond quasi-indipendently to selection. To support his claim, he shows how even with the two best examples of « spandrels », namely the gastropod umbelicus and the female orgasm, what is needed is not a biology of constraints, but « simply careful identification of the developmental unit under selection »⁴⁵.

The influence that Gould and Lewontin's Spandrels still exerts show that the problem of arbitrary atomization is still relevant. While our advanced tools and method can prevents us from making up just-so stories on the basis of current utility, it is hard to understand in which way an organism is adapted to their environment without an « appropriate delimitation of organismal subsets for studies of adaptation »⁴⁶. According to Olsen, trait delimitation is a persistent problem – moreover, it is the great absentee of the Spandrels paper.

Since, despite the technological advancements⁴⁷, we still have not formulated a notion of “part” relly beyond externalism (part as mere adaptation – as criticized by Gould and Lewontin) and internalism (part as constraint/spandrel), Olson proposes a change of metaphor. What we truly learn from Spandrels is not that the organism is “so replete with architectural contstraints” that adaptationist answers have no explanatory power – on the contrary, Spandrels suggests that the notion of adaptation is far more complex and faceted (as section 5 shows!) because of the complex evolutionary relationship between the organism and its parts. An organism is neither a monolithic entity nor a « polymorphous perverse » one. Consequently, a spandrel, which still appears as a left over of previous structures, is to be thought of as a « “an incorrectly delimited trait, one made up of arbitrary subsets of two or more quasi-independent organismal subunits” »⁴⁸. This « reinterpretation » is not just a criticism of Gould's biology of constraints. It emphasizes how a trait, if it is a thing at all, contributes to the whole's fitness as a quasi-indipendent unit of possible evolution – constrained by its context, and yet possibly subject to natural selection in a more or less direct way.

Before moving on, we should notice one crucial detail. Olson admits that, despite all the good will of scientists to avoid biased and arbitrary atomization, when it comes to human beings the chances of error rise. Olson attributes this mainly to the lack of a good method – afterall, « selective breeding, directed mutagenensis, or surgical alteration to create variation »⁴⁹, are likely to elicit the protest of ethical committees at best. When it comes to human behaviour, trait delimitation is an extremely difficult, if not impossible, task.

§4 – Biased biology: Lloyd's proposal.

We are now going to look at Stephen J. Gould and adaptation: San Marco 33 years later, written by philosopher Elizabeth A. Lloyd in 2013. The paper focuses the attention on how still today, 30 and more years after Gould and Lewontin's warning, methodological adaptationism still hinders good scientific practice – especially when it comes to human biology. Lloyd's analysis of the « logic of research questions » (as we have seen, an adaptationist question can accept only an adaptationist answer) allows her to contrast adaptationism with a « “evolutionary factors” approach »⁵⁰ and show how the adaptationist programme is extremely sensible to all biases of sort. As Lloyd's approach puts the adaptationist hypotheses in a different light, we will see how the adaptationist bias is itself like a Trojan horse for biology, especially when applied to human traits.

Lloyd's case study is that of the female orgasm. According to the philosopher, it is a perfect example (and indeed Gould's favourite one) of how negatively adaptationism can affect scientific practice. In her 2005 book The case of the female orgasm Lloyd reports that of all 21 published theories of how female orgasm has evolved, 20 were adaptationist – that is to say, they answered to the question « what is the adaptive function of the female orgasm »? Data about orgasm frequency in women does not show the same pattern that we find when « organisms in a population are selected to have the desirable form of the trait »⁵¹. When rapresented on a graph, instead of a curve signaling selection, such data draw a mostly flat line, indicating that there is no prevalent orgasm frequency: there are as many women that always have an orgasm during intercourse as those who do not, and the same holds for the middle area of the spectrum. Moreover, no correlation has been observed between orgasm frequency and fitness-related traits: « having orgasms is not associated with having more or better babies, the very basis of selective change »⁵². On the contrary, as anthropologist David Symons noticed back in 1979, all the data point in the direction of the female orgasm being a spandrel: since orgasm is strongly selected in males, and males and females share the same early embryological form, being non adaptive per se, female orgasm is a (homologous) byproduct of male adaptation.

Lloyd discusses the « female choice » adaptationist hypothesis, which, while being consistent with the data seen above, is shown to be grounded on baseless assumptions. Given the superficiality of such account, it is hard to ascribe its success and popularity to its scientific rigour. Is it possible that cultural biases have made this hypothesis appear as more satisfying?

According to the female choice hypothesis (also known as the « uterine upsuck account »), « the female will mate with more than one male over either a short period of time, or over different cycles, and have orgasm preferentially with the higher-quality males »⁵³. Being the orgasm accompanied by an “uterine upsuck mechanism”, it can be considered adaptive as it increases the female's chances of being fertilized by a higher-quality male. Such a view presents two major problems.

First of all, in order for this account to be consistent with the data (the flat line mentioned above), a strong selection capable of producing wide variation must be assumed. Such a selective pressure « requires multiple mating by women before insemination »⁵⁴. In other words, it presupposes that the female goes around, so to say, mating with as many males as possible, searching for the best one capable of fertilizing her. Such an assumption is unjustified.

Second, « physiological relation between female orgasm and fecundity […] is usually simply assumed »⁵⁵. No correlation between the “genetic quality” of males and female orgasm frequency has been observed. On the contrary, there seems to be a strong correlation between orgasm frequency (whose data are extremely heterogeneous) and morphological traits of the female⁵⁶ (which are equally heterogeneous).

Despite such flaws⁵⁷, the female choice theory had a huge success:

« many dozens and even hundreds of adaptationists nevertheless used this paper to support their desired conclusion that female orgasm was an adaptation […]. The human evolution field’s instant acceptance of the Baker and Bellis paper [see note 57], and its continuing use of the paper in lectures and teaching, as well as research, was an example of adaptationist bias getting the better of scientific judgment or the application of normal statistical standards »⁵⁸.

Where does the popularity of such unscientific account come from? What is that makes the adaptationist account so preferable despite its evident implausibility? Lloyd is silent about this, but it appears to me that the two assumptions we have seen above have a striking mysoginistic character which may make them particularly appealing. The first assumption gives a biological twist to the « La donna è mobile » stereotype. The second one reinforces the patriarchal narrative that correlates a man's worth to the woman's pleasure, or worse, that submits the woman's pleasure to the man's worth.⁵⁹ Where does adaptationism plays its part in all of this?

The adaptationist research question is: « what is the function of this trait? ». According to its logic, a trait is either functional or not a product of evolution at all. As we have already seen discussing Olson's idea of trait delimitation, a trait is identified only insofar as it is quasi-indipendent. Quasi-indipendency accounts for evolutionary pathways in terms of more or less direct selection. But if a trait has no function per se, then it cannot be a product of evolution, and therefore it does not really exist.

The other side of the coin is that, as Lloyd shows, adaptationists merely see byproduct hypotheses as mere “null” hypotheses, which provide no scientific knowledge. Infact, « When the byproduct hypothesis is treated as merely a non-answer to the adaptive evolutionary question asked, it also cannot be seen as accumulating evidence in its favor »⁶⁰.

Such is the case of female orgasm: it is either adaptive or non-existent, and no evidence can prove its existence as a spandrel. Even Olson, who is well aware of the dangers of adaptationism, ends up saying that « biologists mistakenly regard[...] the female orgasm as a trait independent of that of the male »⁶¹, and therefore denying its delimitation as a trait.

Lloyd proposes a different research question: « What evolutionary factors account for the form and distribution of this trait? »⁶². Its logic not only allows a multiplicity of hypotheses of heterogenous kinds, but also presupposes the every trait is, in various degrees, the result of the interplay of different forces. For example, female orgasm is the result of both natural selection acting directly upon males and developmental constraints. In this way we are able to grant it an “ontological dignity” without having to sumbit it to any adaptive function – in other words, to whatever current utility it has.

§5 – Conclusions.

It is time to draw conclusions. Today most biologists seem to consider Gould and Lewontin's message « passè »⁶³, and yet we find that when it comes to humans, adaptationism (which, as we have seen, is never merely methodological) still exerts its weight. Gould and Lewontin warned biologists « not [to] confuse the fact that a structure is used in some way […] with the primary evolutionary reason for its existence and conformation »⁶⁴. As we have seen, the search for the current utility of a trait, understood as its quasi-indipendent ability of contributing to the fitness of the whole, and therefore being subject to selection and capable of variating quasi-indipendently, implies the problem of trait-delimitation. Atomization and the practice of reverse-engeneering adaptive stories on the basis of current utility appear to go hand in hand.

Human trait-delimitation is an impossibly difficult task – especially behavioural traits. Every “trait” determines our behaviour only through an extremely integrated multiplicity of levels – there is no purely biological, purely psychological or purely cultural trait. The « Spirit » is embodied as much as the body is encultured. Our very ontogenesis is essentially a process of Bildung. Moreover, the evolution of one trait always brings collateral effects upon the whole.⁶⁵

When we try to delimit and identify human « natural traits », we analyse how humans generally behave. Compared to other species, human behaviour is extremely heterogeneous and evolvable, and we usually get to see just one possible « humanity » at a time. In particular, we are always already provided with a set of ideas and values about humans and their behaviours. When we look at them through adaptationist lens⁶⁶, the evolutionary question takes such forms: « how does this trait contribute to the human's fitness for their environment? »; « what kinds of human survive / are the fittest? ». If our social behaviour determines disparities or favours certain traits, we are ready to make up a just-so story for that – if not out of malice, at least because we lack diverse research questions. As behaviour is reduced to the necessary expression of one's nature (i.e. one's genome), developmental conditions and our human exceptional plasticity are ignored. Adaptationism inevitably cements human behaviour into arbitrary and contingent traits, or reduces it to propositions so generic (i.e. « all humans need a shelter ») as to be completely uninteresting. It is, in all respects, a form of justificationism.

While it is not necessary to hold a « gouldian » biology of constraints, an evolutionary-factors approach not only allows a more complex view of selective pressure (which can act more or less directly according to the level of trait-integration), but most importantly, it accounts for human traits in their contingent and non-essential nature. For us, as animals adapting our behaviour to an everchanging environment, trait-delimitation is mostly a matter of functional cooptation – of freedom of working with what we have.

Bibliography.

G. Borgia, The Scandals of San Marco, 1994.

J. Fox, Why "The spandrels of San Marco" isn't a good paper, 2011.

S. J. Gould, R. C Lewontin, The spandrels of San Marco and the Panglossian paradigm: a critique of the adaptationist programme, 1979.

S. J. Gould, The exaptive excellence of spandrels as a term and prototype, 1997.

E. A. Lloyd, Stephen J. Gould and Adaptation: San Marco 33 Years Later, 2013.

R. Nielsen, Adaptationism - 30 years after Gould and Lewontin, 2009.

M. E. Olson, Spandrels and trait delimitation: No such thing as “architectural constraint”, 2019.

M. Pigliucci, J. Kaplan, The fall and rise of Dr Pangloss: Adaptationism and the Spandrels paper 20 years later, 2000.

D. Queller, The Spaniels of St. Marx and the Panglossian Paradox: A Critique of a Rhetorical Programme, 1995.

1See Gould, Lewontin, 1979, pp. 150-151.

2« Pangloss » literally means « all tongue ».

3Ivi, pp. 153-154.

4For example, adaptationists are said to acknowledge the existence of genetic drift, while at the same time downplaying its role in evolution, since its effects are most pronounced in smaller populations (see ivi, pp. 151-152).

5Ivi, p. 151.

6Ibidem. Notice how Gould and Lewontin are using the lexicon of ontology here!

7See D. Dennett, 1995.

8See Gould, 1997.

9Gould and Lewontin, p. 160.

10Ibidem.

11Ibidem.

12See Pigliucci, Kaplan, 2000; Nielsen, 2009.

13Gould, 1997, referring to Borgia, 1994, and Queller, 1995.

14Borgia, 1994.

15See Spandrels, pp. 152-153.

16Borgia, 1994.

17See Spandrels, p. 151.

18Ibidem.

19For example, the « spaniels of St. Marx » are Gould and Lewontin themselves!

20See i.e. Nielsen, 2009.

21Queller, 1995.

22Ibidem.

23Miller, 2000, quoted in .

24Spandrels, p. 158.

25Ivi, p. 159.

26Pigliucci, Kaplan, 2000.

27Ibidem.

28Fox, 2011.

29Ibidem. (See also « variance-covariance matrices » in Pigliucci, Kaplan, 2000.)

30Ibidem.

31Pigliucci, Kaplan 2000.

32Fox, 2011.

33Pigliucci, Kaplan, 2000.

34Against Gould's « analogies and metaphors » (Fox, 2011).

35Ibidem.

36Olson 2019.

37Ibidem.

38Ibidem.

39Gould, 1997.

40Olson, 2019.

41Ibidem.

42See i.e. Gould and Lewontin's own example of marine organisms whose phenotypic plasticity allows adaptive variations while retaining the same genome (Spandrels, p. 158).

43Olson, 2019.

44Ibidem.

45Ibidem.

46Ibidem.

47Genetics is crucial to recognize patterns of dependance or indipendance between traits among the organisms of the same species of phyletic group. The combination of intraspecific delimitations of “modules” with interspecific ones allows us to compare the evolution of different lineages and identify « evolutionarily quasi-independent subunits » (ibidem).

48Ibidem.

49Ibidem.

50Lloyd 2013.

51Lloyd, 2013, p. 25. Although I will use Lloyd's own language and refer to « women », the whole discourse could and should probably be applied to all assigned-female-at-birth people.

52Ivi, p. 26.

53Ivi, p. p. 27.

54Ibidem.

55Ivi, p. 29.

56Particularly, the « Clitoral-Urinary-Meatus-Distance » (p. 28).

57See i.e. much used datas from Baker and Bellis' 1993 research, which « badly violates standard statistical practice » (ivi, p. 29) and is therefore worthless.

58Lloyd 2013, p. 29.

59Conversly, we could notice how the byproduct account, especially as it emphasises the correlation with the woman's own morpholgy, subtracts female orgasm from the male's alleged power and attributes the woman freedom of self-determination – the possibility of, so to say, a political exaptation.

60Ivi, p. 31. Notice how the lack of adequate scientific categories is not just an epistemological problem, but an ontological one, as it influences the public recognition (ἀγορεύω) of the existence of something or someone.

61Olson, 2019.

62Lloyd, 2013, p. 33.

63Ivi, p. 34.

64Spandrels, p. 153.

65This is one of the weaknesses of Dawkin's meme hypothesis.

66Usually tracing their utility back to the survival and reproductive strategies of early humans, as sociobiologists do.