The Female of the Species: Reply to Heartsilver

: Maggie Heartsilver’s “Deflating Byrne’s ‘Are women adult human females?’” subjects the arguments and conclusion of “Are women . . . ?” to a probing and comprehensive stress­test. The present paper responds to Heartsilver’s objections, and also discusses the significance of the proposition that trans women are women.

thinks that fresh arguments are needed-in any event, that is what she supplies. Even if the biological view of gender is wrong, Deflating . . . itself indicates that the philosophers' dismissal has been too hasty.
Section 1 states the biological view more carefully, and makes a prima facie case for it. The next three sections examine Heartsilver's objections to, respectively, the adult, human, and female components, and argue that they do not succeed. Heartsilver also objects to the positive arguments for the biological view given in "Are women adult human females?" (henceforth Are women . . . ?) 9 ; Sections 5 and 6 reply to her chief objections. Section 6 ends with a new consideration in favor of the biological view, based on crosslinguistic data. The final two sections discuss the significance (or otherwise) of the proposition that trans women are women, and of the question What is a woman?.

The Proposition AHF Again
Are women . . . ? argues that to be a woman is to be an adult human female, understood simply as a thesis of modal equivalence: AHF S is a woman iff S is an adult human female.
(The prefix 'Necessarily, for all S' is tacit.) Here 'adult' picks out the mature form of organisms (as in 'adult chimpanzee'); 'human' picks out our species (as in 'humans and chimpanzees have a common ancestor'); and 'female' picks out one of the two sexes (as in 'female chimpanzee'). Adult human female, as it appears in AHF, is thus a biological (and not social) category. 10 Heartsilver argues that AHF is false. The extent of our disagreement may not be completely evident, since Heartsilver departs from the usage in Are women . . . ?, in effect understanding AHF to be the sentence 'S is a woman iff S is an adult human female', writing at one point of "interpretations of AHF." 11 This is why, after arguing that woman is a social category, Heartsilver says that "Byrne can concede that woman is a social category and still defend his thesis that AHF is true or at least a close approximation." 12 But AHF was intended to be the proposition expressed by 'S is a woman iff S is an adult human female' with the words on the righthand side interpreted as indicated in the previous paragraph. 13 "My thesis" is false if this proposition is false. If the sentence 'S is a woman iff S is an adult human female' is true with (say) 'adult' receiving a social interpretation, then I can salvage something from the wreckage. Unfortunately, that will not rescue my sweeping claim that feminist philosophy has seriously erred in dismissing the biological view of gender.
What is Heartsilver's attitude towards the sentence 'S is a woman iff S is an adult human female'? She has some sympathy with the view that it is true, or at least a close approximation, once the terms on the righthand side are interpreted properly. (This already sets her against orthodoxy.) Of course this means that at least one of 'adult', 9 See note 5 above. 10 On categories and the social/biological distinction, see Are women . . . ?, 3784, 2, fn. 1. Note also the qualification made about AHF at 3785. 11 Deflating . . . ?, 7. 12 Ibid., 5. 13 AHF is the proposition expressed by Heartsilver's "BRB" (Deflating . . . , 6), with the word 'reproductively' deleted (see Section 4 below).
'human', and 'female' has a nonbiological interpretation-the first and third, according to Heartsilver. (She is also tempted to replace 'human' with a term that is more inclusive.) Beauvoir's question What is a woman? has an obvious answer: an adult female of our species. 14 (Allow that the "obvious answer" might not be the correct answer.) Moreover, in the pertinent sense of 'adult female', there are adult females of numerous other species which lack societies of the sophisticated human sort; hence, there is nothing essentially social about being an adult female. If the obvious answer is correct, then, AHF is true. Heartsilver may well not agree that this is the obvious answer. Since part of the dispute turns on the initial plausibility of AHF, let me have another shot at motivating it, before getting to Heartsilver's criticisms. 15 Just as knowledge entails truth and belief, woman entails female; at least, these entailments seem roughly equally credible. Beauvoir's The Second Sex has a fine title, surely. And apart from the title, it is clear that Beauvoir accepted the entailment. For instance, directly after the famous "One is not born . . . ," Beauvoir writes: "No biological, psychic, or economic destiny defines the figure that the human female takes on in society." 16 It is also clear that for Beauvoir, 'female' denotes the familiar biological category: the phrase 'human female' indicates as much, and she mentions many nonhuman females in the first chapter. Of course this is no peculiarity on Beauvoir's part: in Kipling's poem "The female of the species," women are only one kind of female, along with female bears and female cobras.
As the quotation from Beauvoir shows, she also assumed that woman entails human. That is also very plausible. In the 1968 movie Planet of the Apes, Dr. Zira is a highly intelligent female primate, a psychologist and veterinarian with a soft feminine voice. A human version of Dr. Zira would be a woman to admire. However, Dr. Zira is a chimpanzee, and hence not a woman.
Not all human females are women, namely the young ones. But they just need to wait. Nothing social or psychological is required: there is no qualifying examination that must be passed or rite of passage that must be endured. The normal biological development of the human organism suffices. When discussing puberty, Beauvoir notes that the timing is different for females and males, with different consequences for when one becomes a woman or a man: "the boy only reaches adolescence at about fifteen or sixteen; the girl changes into a woman at thirteen or fourteen." 17 So here is a third very plausible entailment: adult.
That is a brief case for woman entailing the biological ( Compare knowledge. There are familiar considerations in favor of knowledge entailing truth, belief, and justification. Imagine wondering, in preGettier times, about the reverse. 18 If S has a true justified belief in P, does that absolutely guarantee that S knows P? The best that could be said for an affirmative answer is that it's hard to see what else knowledge could be, other than justified true belief. In retrospect, it is apparent that this only reflects a failure of imagination. Categories like woman are different. Granted that woman entails adult human female, the reverse entailment is compelling. Are there any adult human females who are not women? First, note that once we have conceded that woman entails female and man entails male, trans men are not counterexamples. Since a trans man is not male, he is not a man, and saying that he is neither a man nor a woman seems unmotivated. And once we have got this far, it is a little desperate to search for counterexamples among the socalled "third genders" found in many traditional societies. 19 Second, consider the elementary observation that women are socially and psychologically a diverse bunch. There are women huntergatherers (and hunters), infertile women, lesbians, empresses, women warriors, unmarried women, polyandrous women; there are societies in which children are raised by women in matrilineal households, with husbands visiting their wives at night; 20 there are women with delusional disorders, extreme intellectual disability, dementia; and so on. Naturally there are patterns: human nature, and the social arrangements between women and men, are far from being infinitely plastic, but it is improbable that there is some social or psychological thread running through every single woman across the globe and into our ancient past.
Anthropology and sociology are needed to investigate the hierarchies and kinship structures of societies quite remote from ours. Identifying fellow humans as women or men is much easier. On 22 April 1770, Lieutenant James Cook caught his first glimpse of aboriginal Australians from HMS Endeavour. Sailing along the southeast coast, he saw "several people upon the Sea beach. They appeared to be of a very dark or black Colour; but whether this was the real Colour of their skins or the Cloathes they might have on I know not." Although the indigenous people had remained practically isolated from the rest of humanity for 50,000 years, and Cook knew next to nothing of their ways and customs, a closer sighting a week later revealed "Men, Women, and Children on the S. Shore abreast of the Ship." 21 No extra qualification for womanhood appears to be required: being an adult human female will do nicely. And once the reverse entailment is secured, woman and adult human female are modally equivalent, which is to say that AHF is true.
Heartsilver raises problems for each part of 'adult human female'; let us consider her objections in that order. 18

'Adult'
Heartsilver agrees that 'adult' marks the border where womanhood begins-the dictionary is a reliable guide on this issue, at least-but she thinks that the word has to have a social interpretation. If so, then woman is a social category, in the sense that one needs to be embedded in a society to be a woman.
Against the biological interpretation of 'adult', Heartsilver claims that full maturity into the adult female form "makes womanhood start too early. Most girls complete puberty between the ages of 15 and 17, and many do so earlier than that." It is worth noting that Beauvoir would be unfazed by this worry, since she puts the transition point at "thirteen or fourteen" (see the previous section). Heartsilver is suspicious of my reply, "that 15 and 16 year old girls are 'young women' and hence women"; this, she says, is "a questionable inference given that expressions like 'young man' and 'young lady' are often applied to preteens." 22 But all this shows is that I chose my words carefully. It is true that the singular 'young man/woman/lady/' are used as terms of address when talking to children, which is why I used the plural 'young women' and for safety's sake put it as the subject complement: 'They are young women'. This is just preliminary skirmishing; here is Heartsilver's central objection: There is a wide range of ages at which girls complete puberty, but we do not, on that basis, recognize a wide range of ages at which girls become women . . . Insofar as we are prepared to recognize variability in the age at which people become women or men, it is typically because we recognize that, crossculturally or crosshistorically, variation in social norms has resulted in variation in the age at which manhood or womanhood is reached. 23 Heartsilver's first point in this passage also cuts against her own view. "In the United States," she writes, "we start calling someone a man or woman at the age of 18 or 21 or thereabouts . . . because of social factors such as the new legal rights and responsibilities that are acquired at those ages and cultural norms about the appropriate minimum age for marriage, independence from one's parents, etc." 24 In most of the country, the minimum age for marriage is 18, but in Mississippi it is 21; the other social factors that Heartsilver mentions also vary by state. But we don't normally recognize that American girls become women at different ages depending on where they live. On anyone's view, there is a long penumbral period of adolescence where 'woman' neither clearly applies nor clearly notapplies, and an accordingly high degree of tolerance in the use of the word. When one's 16yearold daughter has been caught shoplifting, one might admonish her by saying 'You are a woman, not a child-act like a responsible adult!' On the other hand, one might plead to the police officer 'But she's only a girl!' The extensive vagueness in 'woman' and 'girl', and the social connotations of being called one or the other, give both Heartsilver and myself ways of accommodating the phenomena she mentions. We can test Heartsilver's second point, about the effects of "variation in social norms," by examining some extreme cases. In 1960 the French historian Philippe Ariès published L'Enfant et la Vie Familiale sous l'Ancien Régime, which appeared two years later in English as Centuries of Childhood. As the blurb explains, Ariès argues that "[u]ntil the 22 Deflating . . . , 4. 23 Ibid. 24 Ibid. end of the Middle Ages, the child was, almost as soon as he was weaned, regarded as a small adult, who mingled, competed, worked, and played with mature adults." As Ariès puts it: "In medieval society the idea of childhood did not exist." 25 The age of maturity, in other words, was lowered close to zero. If that marks the border, Ariès should have described the Middle Ages as populated by fouryearold women and the like. He does not do that, surely correctly: granted that Ariès's history is right, in fifteenthcentury France young females and males remain girls and boys. 26 Instead of lowering the age of maturity, what about increasing it to 100, or abolishing it altogether? In the novel Tarzan of the Apes, the infant Lord Greystoke manages to grow from a "little English boy" into a "man" without any assistance from social norms. 27 Tarzan is very far from literary realism, but in this respect it does not seem odd at all.
The preliminary evidence favors the biodevelopmental interpretation of adult', but we can strengthen this conclusion by examining 'girl' and 'boy'. Heartsilver agrees that it is a "reasonable assumption that AHF stands or falls with" 28 : JHF S is a girl iff S is a juvenile human female.
And, by the same token: JHM S is a boy iff S is a juvenile human male.
A mixed view, where 'adult' receives a social interpretation and 'juvenile' a biological one is quite unappealing. One might argue that describing Tarzan as a boy growing into a man involves an extended use of 'boy' and 'man', perhaps like calling him 'King of the Apes', with 'King' taking its royalty sense. Tarzan was not a monarch, but resembled one enough to make the appellation appropriate. However, saying that Tarzan was first quite literally a boy (as he would be on the biological interpretation) and later a man only loosely speaking, is to find an asymmetry where there is none.
'Juvenile' needs a social interpretation, then. The problem is that there are no "initiation tests" for girlhood or boyhood, although sometimes there are ceremonies like ritual circumcisions or gender reveal parties. In modern societies, there are plenty of rules and regulations applying to children: they must be vaccinated (exemptions are yet more rules), they have to go to school, they are not allowed to get married or to drive a car, and so forth. Could 'juvenile' be interpreted in this positive way, as applying to someone governed by certain obligations or prohibitions?
But in some societies girls and boys do not have a positive social status, they merely lack the social status and attendant obligations of their elders. For instance, in her study of the chisungu, the female initiation rite of the Bemba people of Zambia, the anthropologist Audrey Richards writes that the chisungu teaches: . . . not the technical activities of the wife, mother and housewife, but the socially approved attitude towards them . . . An intelligent nacimbusa [the mistress of the ceremonies] will admit that the girls know how to cook and grind but will say that after her chisungu a young girl does her work in a different way. Such women explain that, when young, a girl can idle in the gardens if she likes and her mother will shrug her shoulders and say 'She is not grown up'; but when she is married she cannot refuse her duties or it will be a cause for divorce. Husbands will scold a lazy wife and this will bring shame on her family. 29 Stressing permissions rather than rights and responsibilities is unlikely restore a positive interpretation of 'juvenile': some societies have no need of norms or rules permitting infants to do things, like ride in a car seat.
Why not solve the problem by interpreting 'juvenile' in the statement of JHF as nonadult? Boys and girls would simply lack the rights and responsibilities of men and women, rather than having special ones of their own. But then this would introduce an asymmetry. Tarzan is literally a boy, but not a man: isolated from society, he never enters adulthood in the social sense. (Even worse, he would remain a boy for the rest of his life.) The Oxford English Dictionary is also inhospitable to Heartsilver: the pertinent definition of 'girl' is female child; with a child being "a young person of either sex, usually one below the age of puberty." 30 This is nonsocial on its face; combining it with Heartsilver's account of 'adult' again breaks the desired parallel between 'boy' and 'man'. 31 Adulthood as a social category leads to too many problems, especially when girls and boys are included. And a final (minor) observation: AHF explains why there is no felt incongruence in using 'adult female' and 'adult male' to denote women and men, where the context forces a developmental interpretation: "women, by comparison with female chimpanzees, perceive adult males as basically equal (though obviously dangerous) opponents." 32

'Human'
Is it necessary that all women are human? Heartsilver is doubtful: she is "inclined to replace...[the] biological notion of human with something broader and perhaps not even essentially biological." 33 Heartsilver does not press this point; still, she raises some interesting cases. Perhaps "some of the remarkable instances of intergalactic convergent evolution in Star Trek are women," and there is "the possibility of cyborg or robotic men or women." 34 She notes that some dictionaries define 'woman' as 'an adult female person'; however, since one sense of 'person' is human being, this is not probative.
To continue with pulp fiction examples from Edgar Rice Burroughs, in A Princess of Mars there are "green Martian women," and Dejah Thoris, the naked and buff 29 Audrey Richards, Chisungu: A girl's initiation ceremony among the Bemba of Zambia (New York: Routledge, 1956/1982), 128. For more on this example, see Byrne, "Appendix." 30 https://www.oed.com, accessed July 2021. 31 On the view Heartsilver suggests, the social component, namely adult, is common to woman and man. Being an adult could be "realized" differently in females and males-the "initiation tests" could be different, for instance-but this cannot be guaranteed. Assuming that female and male are not also social components, on this view there is no constitutive social difference between women and men, which makes it quite unlike standard "social" accounts of gender, inspired by The Second Sex. 32  coppercolored Princess of Helium, is simply "a woman," albeit not an "earthly" one. 35 This way of writing raises no eyebrows. Burroughs's hand was not forced, though: if he had explicitly denied that Dejah Thoris was a woman, instead only using the label 'Martianwoman', this would not have sounded strange either. There is the practice, familiar to philosophers, of denoting the substance on Twin Earth that fits the earthly stereotype of water by the phrase 'Twin Earth water'; Burroughs is basically doing the same thing, sometimes leaving off the prefix. Thoris resembles a woman, as XYZ on Twin Earth resembles water. 36 The Earthling John Carter describes Thoris as having "a slender, girlish figure, similar in every detail to the earthly women of my past life." 37 A subsequent novel, Thuvia, Maid of Mars, features tenlegged "Barsoomian [Martian] lions"; 'lion' is apropos, since they are somewhat lionlike. 38 The aptness of 'lion' for the Martian animal does not show that lions are not the terrestrial species Panthera leo. Replacing 'human' with "something broader" to accommodate gynoids or womanly space aliens risks allowing loquacious female chimpanzees and gorillas into the womenonly tent. That would be a mistake: Dr. Zira is not a woman.

'Female'
So far 'adult' and 'human' are holding up well. Be that as it may, 'female' is the crux. As Heartsilver notes, "intersex" individuals are sometimes held to be counterexamples to the view that woman entails female, and this objection receives extensive discussion in Are women . . . ? Plainly Heartsilver and I do not agree here, but since she does not rest any weight on the intersex case, we can ignore it. 39 I should point out, though, that Heartsilver's characterization of intersex individuals is not standard, and is not mine. She writes: "To be an "intersex individual", as I understand Byrne's use of the expression, is to be an individual who is neither reproductively female nor reproductively male." 40 First, I am not sure why Heartsilver attaches 'reproductively' to 'female'. Perhaps the effect of the adjective was intended to be the same as 'biological', which signals that the topic is not "legal" sex or anything like that. 41 In any case, 'reproductively' is not an ideal term: worker ants are sterile females; queens are "reproductive females." 42 In that sense, a reproductive female is only one kind of female.
Second, although definitions of 'intersex' vary, the basic idea is that the phenotype has both male and female aspects; for instance, in the case of congenital adrenal hyperplasia (CAH), masculinized genitalia with ovaries, not testes. The terminology is 35  extremely misleading (and has evidently misled some philosophers), since it suggests that intersex individuals are "between" male and female, neither one nor the other. In fact, their sex is often not difficult to discern, with CAH being a case in point. 46XX CAH individuals are routinely characterized as female in the literature; moreover, they are typically of the "reproductive" kind. 43 Heartsilver cannot reasonably deny that 'female' frequently has its biological sense when applied to humans, and she does not. Instead, she claims that 'female': . . . can be used correctly in ways that include trans and intersex women and girls as female (and exclude trans men, trans boys, and some nonbinary persons from being female) . . . Such usage can . . . be found on the pages of generalist newspapers and magazines, in the distinction many cis and trans people make between being assigned female at birth and actually being female, in the fact that the law often recognizes that someone who is not reproductively female is nevertheless female, and so on. The suggestion that 'female' has only a single, reproductive meaning, invariant across all contexts, seems to me to be unduly narrow. 44 It is true that 'female' is polysemous. In one sense, certain kinds of electrical connectors are female. More to the point, 'is female' is occasionally used to mean identifies as female or (a somewhat different idea) has a female gender identity, although as far as I can make out this is a rather specialized and very recent use. 45 Here is an example: Essentially, of course, genderqueer or nonbinary people are simply people who are not male or female; but as ever things are more complex than that. In general, nonbinary or genderqueer refers to people's identity, rather than physicality at birth . . . 46 The claim is not that nonbinary people, like the British pop singer Sam Smith, have no sex; rather, it is that they do not "identify" as male or female, or do not have a male or female "gender identity." It is unclear what this amounts to. (In 2019, Smith was "at no stage just yet to eloquently speak at length about what it means to be nonbinary." 47 ) Let us look more closely at the notion of "identifying as female." (Points similar to the ones below will also hold for "having a female gender identity." 48 ) On one interpretation, to 43 Deborah P. Merke and Stefan R. Bornstein, "Congenital adrenal hyperplasia," The Lancet 365 (2005): 2125-36. 44 Deflating . . . , 7; emphasis added. For consistency with the conventions in the text, I have replaced Heartsilver's doublequotation marks with singlequotation marks to mention expressions. 45 It might be thought that this usage is more widespread, on the grounds that on many forms the options for one's "gender" include 'male' and 'female' as well as terms like 'nonbinary', which suggests that the 'female' option should be interpreted as identifies as female, or has a female gender identity. But an equally good interpretation is of the female sex. These forms are not supposed to exclude women who bristle at the notion of gender identity, and so the intended interpretation of 'female' seems to be left purposely unclear. "identify as female" is to allow and facilitate oneself to be taken by others to be female, to accept feminine pronouns uncomplainingly, so on. On another interpretation, it is to have a sense of kinship with other (human) females. (Note that the 'female' in the preceding two sentences has its ordinary "biological" sense.) On yet another, to identify as female is to endorse one's femininity and reject one's masculinity. These do not exhaust the options. But whatever "identifying as female" comes to, 'female' in this sense will not have the extension Heartsilver needs. To see this, let us first summarize the view suggested by the arguments in Heartsilver's paper: 'woman' and 'adult human female' are intensionally equivalent (with a question mark over 'human'), and that in one sense of 'female' (and the corresponding sense of 'woman') "trans and intersex women" are female (and women). Now consider a (nontransgender) butch lesbian who is unbothered by frequent "misgendering," routinely lies when forms ask for her gender, does not feel part of the female club, and who embraces her masculinity. If 'woman' did have a sense corresponding to 'female'asusedtomeanidentifies as female, it would not apply to this person. I do not imagine Heartsilver would be happy with this result. There is no law against using 'female' and 'woman' with semitechnical meanings, but-pace Monique Wittig-there is no everyday sense of 'woman' in which some lesbians are not women. 49 That is one use of 'female' which is of no help to Heartsilver. What about "the distinction . . . between being assigned female at birth and actually being female"? Of course there is a distinction between being assigned female and being (biologically) female: the "John/Joan case," in which a boy who had lost his penis was raised as a girl on the recommendation of the psychologist John Money, is a famous (and notorious) example. 50 This is not what Heartsilver has in mind, however. She is distinguishing between (a) being assigned female and (b) identifyingasfemale (or havingafemalegenderidentity)-"actually being female," as she puts it. So this is just the use of 'female' we have been discussing; as argued, it does not vindicate Heartsilver's claims.
Heartsilver notes that "the law often recognizes that someone who is not reproductively female is nevertheless female." Some natal males are legally female and legally women, and in some contexts one can drop the prefix 'legally'. How does this help Heartsilver? Granted, some trans women are legally female and legally women-for short, are female and women. (Note the presumed nearequivalence between 'adult human female' and 'woman' is playing no role here.) But some trans women are not legally female, or women. And Sam Smith is legally male (there is no "nonbinary" option in the UK). 'Legally female' is no better, for Heartsilver's purposes, than 'femaleidentifying'.
Heartsilver also says that the appropriately inclusive and exclusive sense of 'female' can be found in "generalist newspapers and magazines. There are further problems. 'Female' in the femaleidentifying sense is a recent coinage. If there is a sense of 'woman' induced by the new sense of 'female' then either 'woman' has changed its sense or acquired a new one. It does not seem to have changed its sense, at least not in this fairly radical way. 52 Semantic drift occurs, of course. When James Cook wrote in August 1770 about the "Natives of this Country," he recounted that "we had several interviews with the Men while we lay in Endeavour River, yet, wether through Jealousy or disregard, they never brought any of their women along with them to the Ship." 53 Cook was not applying for a job or recounting his adventures to aboriginal journalists: in the English of Cook's time, 'interview' referred to a meeting or conference-a related sense, but importantly different. Is it really credible that Cook's use of 'woman' is like his use of 'interview'? Scholars of eighteenthcentury English do not seem to think so. Translations of Aristotle's Politics use the word 'woman' without apology; forthcoming translations are unlikely to differ in this respect. And so on.
What about the polysemy alternative? 'Woman' now has two relevant senses, corresponding to the two senses of 'female'. In the biological sense, trans women are not women. In the femaleidentifying sense, let us grant, they are. Presumably those who assertively utter 'Trans women are women' are using 'woman' in its second sense; those who utter the sentence's negation have the first sense in mind. This has nothing going for it. Polysemy does not give rise to seemingly intractable disagreements that are in fact no disagreements at all. If the disputants are talking past each other, this has to be the most spectacular semantic misunderstanding in history. 54 Finally, the view suggested by Heartsilver runs aground for 'girl'. The new sense of 'female' is supposed to apply to trans girls too, with a corresponding change in 'girl'. In the new sense of 'girl', necessarily all girls identify as female, or have a female gender identity. Whatever "identifying as female" or "having a female gender identity" amounts to, these notions do not apply to sixmonth old infants. 55 In the suggested sense of 'girl', we have the absurd consequence that no baby is a girl. (We will revisit this issue in Section 5.2.)

The Arguments of Are Women . . . ?
Heartsilver has objections to each of Are women . . . ?'s six considerations in favor of AHF. Numbered in the order of Are women . . . ?, the arguments concern (1) the dictionary definition of 'woman', (2) gendered animal words, (3) Mitochondrial Eve, (4) baby girls, (5) gender role reversal, and (6) the interchangeability of 'woman' and 'female'. Heartsilver concedes that arguments 1 and 6 may support the truth of the sentence 'S is a woman iff S is an adult human female', but denies that they support AHF because rival interpretations of 'adult' and 'female' are available. (To repeat: 'AHF' is used here as it is in Are women . . . ?, not as in Heartsilver's paper.) She convicts argument 5 of "a common evidential 52 The boundaries of the vague term 'woman' might have shifted slightly, but this applies to vague terms in general. fallacy." She disputes the premise of the (similar) arguments 3 and 4. And, for argument 2, she denies that the premise supports the conclusion. Heartsilver's objections to arguments 1 and 6 have, in effect, already been addressed in Sections 2 and 4. 56 Let us begin with the charge against argument 5.

An Evidential Fallacy?
Argument 5 is that AHF predicts the right result in cases of gender role reversal, as in the journalist Norah Vincent's research project of living as a man. 57 Even if she had taken method acting to the limit, and believed that she was a man, she would have remained a woman. This data point thus supports AHF. Heartsilver objects that the argument: . . . commits a common evidential fallacy. For there are serious views on the truth conditions for 'S is a woman' that are incompatible with AHF . . . that also correctly predict that gender role change does not change gender. 58 The last part of the quotation is right. And it is a fallacy to move from 'E confirms H' (i.e., Prob(H/E) > Prob(H)) to 'Prob(H) is high', 'Prob(H>1/2)', or anything of the sort. But no such fallacy was committed. Imagine that Poirot suspects that the deceased Dr. Black was poisoned by Mrs. Peacock. The discovery of arsenic in Dr. Black's blood supports Poirot's hypothesis, notwithstanding the fact that it also supports the hypothesis that Black committed suicide by ingesting rat poison. Absent further evidence, it would be a mistake for Poirot to jump to the conclusion that Peacock is the culprit, but when Poirot discovers that Peacock is Black's heiress, that Black was about to get married to his soulmate Professor Plum, and so on, the Peacock hypothesis starts to look worthy of belief. That is all that is going on here. As Heartsilver emphasizes, alternative hypotheses must be considered. Are women...? discusses some of them; it is not difficult to show that AHF's rivals have serious problems.
In fact, in a footnote appended to the quoted passage, Heartsilver gives an example, citing DíazLeón's view as a rival hypothesis to AHF that also secures the right result in genderreversal cases. 59 Does it?
Although DíazLeón advertises her view as a "contextualist" account of 'woman', it is actually a version of subjectsensitive invariantism, familiar from epistemology. 60 In the epistemological case, the idea is that the truth of 'S knows P' depends partly on S's interests as well as the usual epistemic factors. In the gender case, fixing on a person X in a certain situation or context, 'X is a woman' is true: . . . if and only if X is similar to most females with respect to the standards that are relevant in X's context, given the practical purposes that are relevant in this context . . . where these are broadly conceived to include theoretical, prudential, moral, political, and even aesthetic values. 61 56 See Byrne, "Appendix," for a discussion of two other objections from Heartsilver. 57 Are women . . . ?, 3789. 58 Deflating . . . , 11. 59 Deflating . . . , fn. 33, 11. The citation is to Esa DíazLeón, "Woman as a politically significant term: A solution to the puzzle," Hypatia 31 (2016): 245-58. 60 See, e.g., John Hawthorne, Knowledge and Lotteries (Oxford: Oxford University Press, 2004), ch. 4. DíazLeón herself is "neutral" on whether the term 'contextualism' is appropriate; see "Woman as . . . ," 256, n. 9. 61 Ibid., 249, emphasis added, the two parts of the quotation transposed.
Illustrating how this is supposed to work, DíazLeón supposes that a trans woman, Charla, wants to use the women's restroom: . . . it is plainly false that the relevant standard in this case is whether Charla has XX chromosomes (or a vagina), because there are plenty of moral and political considerations in support of the view that this is not the relevant criterion here . . . the criterion that is relevant here is whether Charla selfidentifies as a woman, or something along these lines. Therefore, it will be plainly false that Charla is not similar to most females with respect to the relevant criterion at issue here, because the relevant criterion is how Charla selfidentifies, not what kind of chromosomes or genitalia she has, and with respect to that criterion she is clearly similar to most females, so ['Charla is a woman'] will turn out to be true. 62 Now imagine Norah Vincent in her manly disguise-at least in one sense, "selfidentifying" as a man-wanting to use the men's bathroom. Using the women's bathroom would be distressing not just to Vincent but also to other women present; it would also, we may suppose, thwart her admirable feminist ambition to expose the patriarchy from the inside. The men's bathroom presents no disadvantages at all. There are "plenty of moral and political considerations in support of the view" that Vincent's female sex is not the relevant criterion, but instead selfidentification or something like it. Therefore DíazLeón's view appears to incorrectly predict that (evaluated at the relevant time) 'Norah Vincent is a man' is true. The rival view cited by Heartsilver turns out not to be much of one.

Baby Girls
Argument 3 in Are women . . . ? is that AHF explains how we know that the prehistoric Mitochondrial Eve is a woman from the evidence that she was female and bore children. The similar argument 4 is that JHF (see Section 2 above) explains how knowledge that a certain baby is female is invariably accompanied by knowledge that the baby is a girl. For reasons of space I will focus on the latter. 63 Heartsilver's reply to argument 4 is that knowing the sex at birth is not enough: we also need to rule out that the baby "is not trans." 64 The main target of argument 4 was a view on which being a girl is partly a social matter. The point was only that AHF offers a simple explanation of our easy knowledge that newborn females are girls, not that no rival account could possibly explain it.
In any event, does Heartsilver's reply really make any sense? What is it to be "trans"? Heartsilver has her own stipulative definition of 'trans woman', on which it involves "sincerely believing" that one is a woman, which I will discuss later (Section 7). A parallel definition of 'trans boy' would obviously prohibit newborn infants from being trans boys, so charity suggests that in this part of her paper Heartsilver is using 'trans' in another way.
Since Heartsilver appeals to MerriamWebster to support her point about the "gender identity" sense of 'female', let us turn to the entry for 'transgender [person]', which gives this completely standard definition: "a person whose gender identity differs from the sex 62 "Women as . . . ," 249-50. This passage also suggests that an adult female-call her 'Chloe'-could be in a situation in which the "relevant standard" is whether Chloe "has XX chromosomes (or a vagina)." If Chloe has atypical sex chromosomes (e.g., XO) and/or has MayerRokitanskyKüsterHauser syndrome (no vagina at birth), then 'Chloe is a woman' is false, the wrong result. 63 For discussion of Heartsilver's worry about argument 3, see Byrne, "Appendix." 64 Deflating . . . , 10-11. the person had or was identified as having at birth." And the dictionary also gives a completely standard definition of 'gender identity': "a person's internal sense of being male, female, some combination of male and female, or neither male nor female." 65 Newborns do not sincerely believe that they are boys or girls; neither, we may reasonably suppose, do they have an "internal sense" of being male or whatever. And if they don't, they are not trans-for the same reason, they are not "cis" either.

Ewes and Rams
Are women . . . ?'s argument 2 begins by noting the crosslinguistic pattern in gendered animal words. Pairs like 'ewe'/'ram' and 'duck'/'drake' evidently answer to some widespread need. Uncontroversially, a ewe is an adult female sheep, and a duck (in the pertinent sense) is an adult female duck. Wouldn't English have a similar pair for humans? If so, it must be 'woman' and 'man'.
Heartsilver observes that the picture is complicated. For instance, in one sense of 'sow' a sow is an adult female bear or an adult female swine, but in another the word applies only to "female pigs who have had a litter." 66 The latter sense, as Heartsilver says, "is likely to have been shaped by social interests related to pig farming." Other examples include 'capon' (a capon is a castrated male chicken), and 'heifer' (a heifer is a cow that has not calved). But these examples, although they no doubt exist because of agricultural interests, do not denote social categories. Sows, capons, and heifers are not constitutively connected to humanlike societies, although a naturally occurring capon would be a curiosity. So far, Heartsilver has not lessened the expectation that English should have a pair corresponding to 'goose'/'gander'-'woman' and 'man' are clearly not restricted in the manner of 'heifer' and 'capon'. 67 Her next point would be decisive, if it were correct: The term 'sow' requires for its correct application adulthood only in the sense of sexual maturity, but the term 'woman' at least typically requires, for its correct application, adulthood in a different, social/legal sense . . . 68 However, as argued, it is not correct. Relatedly, Heartsilver tries to drive a wedge between humans and other animals by noting that 'mother' and 'father': . . . are more likely to pick out biological categories when applied to nonhuman animals. Applied to humans, on the other hand, there are both social and biological senses of these terms. Thus, an adoptive mother is a mother despite her lack of biological credentials, and not just metaphorically or figuratively. 65 All quotations from https://www.merriamwebster.com, accessed July 2021. 66 Deflating . . . , 14. 67 English has a counterpart to 'capon', namely 'eunuch'. A eunuch is a castrated human male. (The word also has a social meaning, applying to castrated males who guard women, as in imperial China.) Males castrated before puberty do not undergo the normal process of development into the adult form, and they end up looking quite distinctive. For example, they grow to be taller than average, because the absence of testosterone means that the growth plates in the long bones fuse later. (See Carole Hooven, T: The story of testosterone, the hormone that dominates and divides us (New York: Henry Holt, 2021), 28-31, 120-21.) On the biological view eunuchs castrated later are straightforwardly men, while eunuchs castrated earlier are less clear cases, which seems right. 68 Deflating . . . , 14.
'Adoptive mother' is not exclusive to humans; it can also apply to other primates, for example. 69 'Mother' and 'father' are not gendered animal words like 'hind' and 'stag', or 'lioness' and 'lion'. The fact that 'mother' applies, not just to birthing females but also to females who play the motheringrole, does not suggest that humans will be an exception to the 'mare'/'stallion' pattern.
Heartsilver's last point looks more promising: Nor is there really a need for a term in English to pick out the female members of our species, for the word 'female', used as a noun, fulfills that function . . . in most contexts the word 'female' by itself, unaccompanied by the modifier 'human', is everywhere used correctly and unambiguously to talk about female humans specifically . . . Thus, there is no need for the word 'woman' to fulfill the function of words like 'doe', words that denote the reproductively female members of the species. 70 Heartsilver is right that 'female' usefully serves "to pick out the female members of our species," but that includes girls. 'Woman' is the word to use if one wants to talk only about the mature variety. Much more importantly, these are parochial features of English. Are women . . . ? noted that 'woman' is a good candidate to be a lexical universal, but equivalents for 'female' are not present in all languages. 71 Granted that a word for the (adult) female members of our species would be extremely handy, some languages can't make do by repurposing their word for females, because they don't have one. They do, however, have a word that translates as 'woman'.
A closer look at words that may be lexical universals yields additional support for AHF, and a last objection to the social interpretation of 'adult'. The candidates are few; here are half of them: 'woman' 'man', 'child', 'mother', 'head', 'eye', 'hand', day', 'kill', 'good', 'big', 'know', 'want', 'see', 'below', 'inside'. 72 Nothing is explicitly social: no 'chief', 'priest', 'midwife', 'village', celebration', 'feast', and so on, and most of the words are clearly nonsocial, in the sense of not requiring the existence of human societies for their correct application. The psychology that is explicitly recognized is pretty basic: knowledge, thought, perception, desire. Not even emotions make the list. The idea that a lexical universal covertly smuggles in anything like "gender identity" is farfetched. The crosslinguistic evidence does not sit happily with the idea that to be a woman involves having some sort of social status or psychological configuration.

Trans Women
It is now time to turn to Heartsilver's claim that "Byrne's arguments provide no reason to deny that trans women are women," and the significance (or otherwise) of this 69 Nahoko Tokuyama et al., "Two wild female bonobos adopted infants from a different social group at Wamba," Scientific Reports 11 (2021): 4967. In a footnote (Deflating . . . , 14, fn. 40), Heartsilver refers to Chappell's analogy between adoptive parents and trans women/men; this is examined in Byrne, "Appendix." issue. 73 I should emphasize at the start that the point of Are women . . . ? was simply to argue for the-bizarrely neglected, as I saw it-biological view of gender. Trans women only appeared in that paper because feminist philosophers have cited them as counterexamples. That said, unless one has eccentric views about sex in mammals, it is a straightforward corollary of AHF that trans women are not women. Heartsilver does not explicitly deny that the sentence 'Necessarily, all women are female' is true, but tries to avoid the corollary by finding a validating sense of 'female' other than the standard biological one. One moral of Section 4 is that there is no such sense.
The claim that trans women are women is the locus of considerable controversy, dividing "trans rights activists" (TRAs) from "gender critical feminists" (GCFs). (Predictably, each label is under fire from the other side: the TRAs may complain that they are gender critical too, and that anyway the GCFs aren't feminists; the GCFs may protest that they support trans rights as much as the next person. 74 ) Since Heartsilver says in her abstract that she will be defending "the proposition that trans women are women" against the arguments of Are women . . . ?, one might think that Heartsilver is addressing this very public and heated dispute, siding with the TRAs over the GCFs. This is not quite right, though. Heartsilver stipulates that for the purposes of her paper: . . . 'trans woman' means 'someone who was born reproductively male but sincerely believes that they are a woman'. (The definition is intended merely to roughly capture the extension of 'trans woman'. I am not suggesting that anyone's gender is reducible to a belief.) 75 As Heartsilver clearly recognizes, this stipulation does not come close to capturing the ordinary understanding of 'trans woman'. First, a "sincere belief" is not necessary. Recounting her life to the journalist Buzz Bissinger, at one point Caitlyn Jenner says: I am firmly on the side of womanhood now. But I am not a woman. Nor will I ever be.
I am a trans woman. There is a difference. 76 If anyone is a transgender woman, Caitlyn Jenner is.
Second, Heartsilver's stipulation does not provide a sufficient condition. A baby boy abandoned at an isolated convent and raised by nuns for whom men are mythical creatures might grow up to believe that he is a (rather unusual) woman. This would not make him a trans woman. 77 We can sidestep worries about sufficiency. Put in standard English, Heartsilver wants to defend the claim that trans women who believe themselves to be women, are women. Moreover, she is careful to emphasize that this allows for exceptions: Even on this definition, I agree with Byrne that not all trans women [who believe themselves to be women] are women because I believe that one can be mistaken about one's own gender. Thus, I am concerned to show only that Byrne's article provides no reason to doubt the generic proposition that trans women [who believe themselves to be women] are women. 78 Why does Heartsilver not simply endorse the generic proposition that trans women, sans qualification, are women? Because, using 'trans woman' in the usual way: . . . some trans women do not believe that they are women, and I am certainly in no position to claim that such persons are mistaken about their own gender. 79 Au contraire. Although Heartsilver says at the end of her paper that her comments have been "entirely negative," and that she has provided "no justification" for her view "that trans women [who believe themselves to be women] are women," this is false modesty. As we have seen, she gives arguments supporting the view that women are socio/legal adults, and that women are people in a sense that transcends our species. She also claims that in some genderidentity sense, trans women and girls are female, while "trans men, trans boys, and some nonbinary persons" are not. Although she is skeptical of the project of providing "necessary and sufficient conditions" for being a woman, by her own lights she has come fairly close. Deflating . . . 's arguments point to the view that to be a woman is to be a socio/legal adult person, with a female gender identity. 80 Consider two trans women, Alice and Beth, who have very similar pathways to transitioning, with one ending up believing that she is a woman while the other ending up believing the opposite. This is not at all fanciful: transitioning from one sex to the other, or ending up somewhere in the middle, is a highly unusual and disorienting experience, and different transitioners may make sense of it in different ways. 81 Formally, Alice and Beth could both be right, but is that realistic? The only relevant difference is that Alice believes that she is a woman and Beth doesn't.
Could gender identity come to the rescue? As we have seen, Deflating . . . 's arguments suggest that to be a woman is to be an adult female person, with 'female' given a gender identity sense. However one interprets 'adult' and 'person', Alice and Beth are adult people, so if Alice is a woman and Beth isn't, the burden falls on 'female'. And if having a "female gender identity" requires believing that one is (biologically) female, then Beth is not female (in the gender identity sense), but (we may suppose) Alice is. On this version of the Deflating . . . view, Alice is a woman and Beth isn't, so they are both right.
However, although Alice gets her womanhood right, the price is that she gets her sex wrong-she is not a (biological) female. And anyway this account of gender identity is 78 Deflating . . . , 2. In this quotation, read 'trans women' in the usual way, not as stipulatively defined by Heartsilver. 79  overly restrictive-a female gender identity is not usually supposed to require the belief that one is female. And if it doesn't, Alice and Beth are both women, so Beth is the one in error. On any halfway defensible view, either Alice or Beth is mistaken. The errors ramify. 82 This may seem presumptuous, but the conclusion cannot be avoided. Neither is it at all surprising: selfconceptions are often wrong, and struggling with gender dysphoria and its social consequences can hardly improve accuracy.
Assume that AHF is true, and so that trans women are not women. What follows? Since GCFs frequently affirm the conclusion, and TRAs proclaim the opposite, one might think: a lot. As an illustration, take the issue of whether trans women should be permitted to compete in women's sports. The journalist Nathan Robinson writes: Note that if you believe in full trans acceptance, the debate doesn't even arise. If trans women are women, then of course they should get to compete in women's sports. 83 Why Robinson links "full trans acceptance" to trans women being women is baffling, but in any event his 'of course' is of course wrong. If the 50 Foot Woman wants to join the women's basketball team, then she may reasonably be denied. Pleading that she is really a woman would be to perversely insist on the letter instead of the spirit. Similarly, Typhoid Mary should be kept away from women's bathrooms. Conversely, if Dejah Thoris, with her musculature formed in Mars's weaker gravity, wants to play women's sports, why on Earth not? And no one complains about a small boy accompanying his mother into a bathroom with 'Women' on the door.
The sports issue turns on the athletic advantages conferred by a male puberty, balanced against the interests of natal males who move through life socially as women, not on whether trans women are women. 84 The same point holds for any similar locus of dispute, say about access to women's prisons or shelters, or "selfID" laws. 85 The GCFs hold that females are an important political class, deserving of their own advocacy movement. 86 They are selfdescribed feminists, and since feminism is naturally thought of as "the advocacy of women's rights on the basis of the equality of the sexes," terminological awkwardness ensues if it turns out that natal males can be women. GCFs are therefore motivated to think that woman entails female. On the TRA side, if one wants to ensure that trans women are treated as women in every circumstance, it is rhetorically extremely convenient if it turns out that trans women are women. No surprise, then, that following the justquoted explanation of feminism from the US LGBTQ lobbying group 82 For instance, consider two latetransitioning trans women, Clarissa and Diana. Both believe they are women, but Clarissa believes she was a woman before her transition, and Diana doesn't. Or consider two nonbinary individuals, Eden and Flynn. Both natal males, Eden believes that they are a (nonbinary) man, while Flynn believes they are neither a man nor a woman. 83 87 But, to repeat, the substantial issues can (and should) be stated and debated without taking a stand on this issue. And-needless to say-the imperative to be respectful and polite needs no support from the metaphysics of gender.

Beauvoir's Question Revisited
The question What is a woman? has been held by many feminist philosophers to be central to feminism. Heartsilver demurs, for good measure ending her reply with a fusillade of miscellaneous objections, in case her earlier bombardments might have left a few survivors. Beauvoir's question is unlikely to be answered, Heartsilver says, because "natural language is a chaotic mess . . . such a mess that we should not expect to be able to provide logically necessary and sufficient conditions for the correct application of most ordinary predicates." 88 That does not directly address my arguments in favor of AHF, and (as Heartsilver notes) Are women . . . ? does issue some cautions. The chaotic mess does not stop Heartsilver from claiming that 'doe' "can be used to refer to juvenile female deer," or from arguing that woman are social/legal adults, and so on. 89 Once one admits that in some cases there are nontrivial sufficient conditions, and in other cases nontrivial necessary conditions, there is the possibility of nontrivial necessary and sufficient conditions, messiness notwithstanding. Further, to address the issue that Heartsilver is most concerned with, all we need is to examine whether woman entails female.
Heartsilver has another reason for pessimism: "the target may be moving as more people are beginning to use 'woman' and even 'female' in a way that includes trans women in the extension of these terms." 90 This seems to concede that the old meaning of 'woman' excludes trans women, which I presume Heartsilver did not intend. In any case, this blurs two different understandings of the "use" of a word. In one, a word w is used to include x when w is applied to x; in another a word w is used to include x when w applies to x. It is true that more people are applying 'woman' to trans women; it does not follow that the word has changed meaning, and now in fact applies to them. If we take apparent disagreement at face value, these people are applying the word 'woman' with its ordinary old meaning to trans women, because they think that trans women are women. They are not using 'woman' with a novel meaning-if they were doing that, there would be no dispute.
There is a clear contrast with 'female', which in one way does present a moving target. As Heartsilver points out, 'is female/male' has sprouted a novel meaning, roughly has a female/male gender identity. In that sense, Sam Smith is neither male nor female, or perhaps a bit of both. Any initial confusion about what is going on can be sorted out quickly; after that, and waiving any reservations about the notion of gender identity, we can all agree that Smith is neither male nor female. At least some trans women will be female in this new sense. One might have reservations about using 'female' with this meaning, but that is not to disagree with the claims that are made using the word.
The old meaning of 'female' persists alongside the new one, and it is perfectly clear that some people apply the word 'female' with its ordinary old meaning to trans women, because they think trans women are female. 91 They are not using 'female' with a novel meaning-if they were doing that, this case would collapse into the case in the previous paragraph, and any dispute would vanish.
Next, Heartsilver pours some cold water on the debate over AHF. I agree with her that if AHF is true, this is not of much "theoretical significance." 92 It is of no more theoretical significance than the parallel claim that to be a ewe is to be an adult female sheep; that 'woman' can be added to 'ewe', 'tigress', 'hen', . . . is exactly what naïve expectations suggest. But-and here I disagree-if AHF is false, that is of great theoretical significance, even more so if woman does not entail female. If AHF is false, something strange and interesting is going on, and Beauvoir's question becomes urgent, whether one has feminist motivations or not.
Heartsilver downplays the significance of AHF in another way, saying that "the corresponding debate strikes [her] as a mere verbal dispute." Her point is not that the disputants are using 'woman' with different meanings. Rather, it seems to be the much more radical idea that the sentence 'S is a woman iff S is an adult human female', if true, is "true in virtue of meaning" and not true in virtue of the world, in some way metaphysically lightweight: "the truth value of AHF depends entirely on what the word 'woman' means." 93 The problem is in justifying the use of 'entirely': the truth of 'Jede Frau ist eine Frau' depends partly on the meanings of its components, just like any other German sentence. From the meaning of its components we can derive that 'Jede Frau ist eine Frau' is true iff every woman is a woman; and reach the further conclusion that the German sentence is true because every woman is a woman. I do not think anyone has ever satisfactorily explained how the meaning component can secure truth all by itself. 94 Heartsilver has a final device to be detonated if all else fails: "people should use words as they like so long as they are guided in their usage by a proper concern for justice and for the wellbeing of others . . . analytic philosophers in the seminar room may not like the way I use the term 'woman' . . . but why should I care?" 95 The first part is surely right, but the principal complainants are not fingerwagging language mavens or nitpicking analytic philosophers, as Heartsilver implies. Rather, the objection is that our fellow human beings deserve clear and nondeceptive communication, interpersonally and from institutions. Much worse than ignorance is believing without knowing, an unknown unknown. Kant may have overegged his strictures against lying, but he was on to something.
A few years ago, the UK charity Stonewall devised this slogan: "Trans Women are Women. Get Over It!" 96 If standard English was intended, and assuming that the slogan is false, then the interests of trans people are not wellserved. 97 Perhaps Stonewall could reply that they believed the slogan was true. But if Stonewall thought that this was a noble lie-or wrote in their own idiolect, not caring whether their proprietary sense of 'woman' matched the standard one-then this would have shown complete contempt for the audience, including their own constituency.
On the same theme, suppose it is false that trans boys are boys. Should authority figures tell genderdysphoric female children that trans boys are boys? I am not answering that question, just pointing out that it cannot be brushed aside as a trivial semantic issue. AHF has little significance for public policy, sporting regulations, the treatment of gender dysphoria, or personal relationships. Its importance lies elsewhere.
Whether AHF has passed Heartsilver's stress test with flying colors is for the reader to judge. Whatever the verdict, Heartsilver has undoubtedly contributed to our collective endeavor, and I greatly appreciate her willingness to engage. I look forward to the return of academic business as usual, when anonymity in these debates is no longer needed.