Concocting Sex

 

Can you imagine trying to conduct biological research in the mid-300s BC? Without the use of gene sequencing, computational models, or even a microscope? Before Galen, Linnaeus, and Darwin? How would you go about trying to answer biological questions like: what causes offspring to be male or female? Aristotle's deep and far-reaching philosophy of nature tried to account for this very sort of phenomenon, using evidence from observations that he could make without our powerful modern technologies and leveraging the richness of his theoretical framework. 

In Book IV of the Generation of Animals, Aristotle presents his causal explanation for the sex of embryos. Roughly, on his view, animal bodies "concoct" the nutrients from food into blood, and then even further (in the case of male bodies) into semen. In Aristotle's terminology, the process of concoction is something like distillation, or ripening, and requires sufficient heat to achieve successfully. Aristotle believes that, generally speaking, males are hotter than females and that as a result, males can concoct blood into semen whereas females are incapable. Semen carries what Aristotle calls "the principle form" or "the first moving cause" (765b). Whether an embryo ends up male or female according to Aristotle depends on whether the principle form within the male's semen "prevails" over (sometimes rendered as "masters") the contribution to the development of the embryo from the female. If it does prevail then the embryo becomes male (and resembles his father in accordance to how purely the semen was concocted), and if "it is prevailed over it changes into the opposite or is destroyed"--and the opposite of male is female (766b). Although the semen produced by (hot) males carries the principle form, the "corresponding secretion of the female" does not and instead "contains material alone" (ibid., although there is a footnote attached to this phrase in the translation I'm looking at that reads: "This sentence looks badly corrupted", which although unfortunate is not surprising given the antiquity and history of transmission of this work). 

Using this explanation, Aristotle then purports to account for such implications as that more females are produced from the very young and very old, "those of a moister and more feminine state of body", in conditions where the semen is more liquid (rather than thicker), when the south winds are blowing (which are moister than the north winds), etc. (766b).

Aristotle has been interpreted as claiming that the process that produces a female embryo is a failed version of the process that produces a male one--that females are in a sense defective results of a process that should have (if successful) produced males. 

Could we imagine, given the resources that Aristotle had available to him, a different explanation for the sex of embryos? Was there a sense in which the evidence available to him forced Aristotle into an explanation where the female is incapacitated? Where the generation of females is a kind of failure? 

In a sense, such explanations are easy to come by. After all, Aristotle himself admits of the possibility that the principle carried by the male secretion does not prevail--i.e. that it is prevailed over. Could that not indicate a kind of capacity of the corresponding female secretion to prevail? Insofar as Aristotle's account denies that the female secretion carries any "principle form" perhaps it does not make sense to count the failure of the principle from the male secretion to prevail as a case in which the female secretion prevails, precisely because the female secretion carries no principle form. But why not?

It is interesting that Aristotle himself allows that some males can be less hot and moister than others, which could inhibit the concoction process thereby yielding female offspring. What about the case of a certain instance of copulation in which the female happened to be exceedingly warm, the male not so much, and the north winds are blowing? Why would that not result in sufficient concoction?

Gelber (2018) helpfully distinguishes between two positions that we could attribute to Aristotle: 1) that females are inferior to males, and 2) that females are the result of a defective generative process and then argues that while there is ample evidence that Aristotle endorsed the first claim, the case can be made that he did not necessarily endorse the second. Consider for instance, this somewhat subtle passage from the Generation of Animals:

For even he who does not resemble his parents is already in a certain sense a monstrosity; for in these cases Nature has in a way departed from the type. The first departure indeed is that the offspring should become female instead of male; this, however, is a natural necessity. (For the the class of animals divided into sexes must be preserved, and as it is possible for the male sometimes not to prevail over the female in the mixture of the two elements, either through youth or age or some other such cause, it is necessary that animals should produce female young.) (767b.)

 In this passage, Aristotle apparently claims that the generation of females in a natural necessity. Indeed, Gelber reads Aristotle as appealing the "motions" and "potentials" of the female generator that can be responsible for the resemblance of an offspring to its mother, or its maternal relatives. Gelber argues that "it is the possibility of the male motion not mastering that makes female births necessary" (186). 

Even if the generation of females is necessary on Aristotle's account, could one still argue that females result from a deficient process? I have to admit I am not sure--I would need to think it over more.

Regardless, it does not seem to me that the evidence available to inquirers in the mid-300s BC would have forced them to adopt the view that females are the result of a failed generative process. One could perhaps have argued that there were male and female "motions" and that which prevailed depended on various auxiliary conditions. Gelber argues that Aristotle himself does not appear to have held this view--it is too egalitarian to reconcile with other aspects of his work--however, just because Aristotle did not in fact endorse this view does not rule out the possibility that someone else with his evidence might have endorsed it. To account for Aristotle's view itself, we probably need to appeal to the norms of the society in which he was steeped rather than evidence and reason alone. 

Recommended: Gelber, Jessica. "Females in Aristotle's Embryology." In Aristotle's Generation of Animals: A Critical Guide, edited by Andrea Falcon and David Lefebvre, 171-187. Cambridge University Press, 2018.

Photo credit: Nantahala Farm