It’s a fairly common occurrence that I see comments directed to trans people along the lines of “Trans people are denying science” “Science says penis= boy and vagina = girl” “Science says males have XY chromosomes and females have XX chromosomes”, “It’s basic biology, people”, and so on and so forth.
What do we mean by science? Well, my high school memory of what we were taught about science (from Karl Popper) is that the basic requirement is for a hypothesis which is falsifiable. So for example, the statement that “All swans are white” is a hypothesis which can be proved false if I see a black swan. Seeing millions of white swans does not conclusively prove the hypothesis to be true (though may strongly support it, and in practice we sometimes have to work with the best theory we have), but the moment a black swan is observed, the hypothesis is proven false.
“All men have penises” is, on the face of it, a similar statement to the one about swans. It’s falsifiable if I can find a man without a penis. However, for this to work, we have to have a way of defining “man” which does not involve reference to penises. Otherwise, there is a logical fallacy. To go back to the swans, if I say “All swans are white”, and then I see a black swan and say “No, that is not a swan because swans are white, so that black thing cannot be a swan”, I have made a circular argument. If my definition of a swan requires it to be white, and I will not accept anything that is not white to be a swan, my premise is unfalsifiable. Therefore, it is not a scientific hypothesis, but simply a statement of how I am defining swans.
Now, I expect that if I got the leading world scientific experts on swans together, they’d probably all agree on what a swan is. They’d probably base their definition on a number of long-standing principles and conventions within biology and taxonomy about how to define a species. It would be possible to assess a definition of a species against those conventions. But all the same, that’s still only a convention of how biology goes about definition and classification, not scientific proof that those conventions are correct. And of course, scientific conventions are ultimately rooted within the society that scientists operate in. Why are swans also known as Cygnus, of the family Anatidae? It’s not because it is scientifically proven that Latin is the best way to describe birds. It’s because of the historic position of Latin within academia. This in turn can’t be entirely separated from social issues. Latin’s status as a language of learning derives from the role of religion in society. And throughout the last few hundred centuries, upper-class men have had far more access to Latin than working-class women. The definition swan = Cygnus is not a scientifically proven fact, it is a scientific convention, which arose within a particular social structure, and which is not neutral on issues of class, religion and gender.
Back to penises. There are scientific hypotheses which could be posited on the penis question which are falsifiable, and which do not contain circular logic. For example, the statement “Everyone with XY chromosomes has a penis” is clearly a testable, falsifiable hypothesis. So is “Everyone with testosterone levels between 8 and 30 nmol has a penis”. And “Everyone who self-identifies themselves with the social category man has a penis”. And “Everyone who is legally recognised under UK law as a man has a penis.” However, these hypotheses are not merely falsifiable – they have already been proven false. Remember, you only need one exception. One black swan proves that not all swans are white; one person with XY chromosomes and no penis proves that XY chromosomes =/= penis. The scientific method does not allow you to dismiss exceptions to your hypothesis on the grounds of being uncommon.
The problem here is with insisting upon a categoric statement about “All” or “Everyone”. Saying “Having XY chromosomes very strongly statistically correlates with having a penis” or “More than 98% of self-identified men have a penis” are falsifiable, scientific hypotheses which are very strongly supported by the evidence. But clearly they do NOT prove that penis = man.
The whole “science” argument gets even more unscientific when we get into practical implication. Biology has nothing to say about which bathroom trans people should use. I mean, we could derive a hypothesis and test it – “People with penises empty their bladder more efficiently if they are doing so behind a door showing a stick figure wearing trousers” – but I don’t think anyone would seriously expect anything other than a null result in a double-blind randomised controlled trial. Now, social science might well tell us a lot about social views about gender-segregated bathrooms, and why some people might feel upset or confused or threatened if their expectations about bathrooms are not met. But social science would explicitly recognise the role of social norms, and would not claim to have discovered an objective, eternal truth about where people should wee.
The problem is not that trans people are anti-science. The problem is that many of our critics don’t know what science is.