If, as noted last time, its proponents don’t argue that all trans women are women (TW), why does anyone believe it? Byrne continues,

A reasonable conjecture is that the insistence on TW by trans women themselves has had some influence. And isn’t that evidence for TW? After all, when someone declares ‘I am an F’ that is often a strong indication that she is an F. In the present case, however, this is unpersuasive for a perfectly general reason: if someone is personally heavily invested in the truth of p, it is prudent to treat her claim that p is true with some initial caution. And in any case—this can hardly come as a surprise—trans women themselves are not of one mind on TW.

He then quotes various “trans women” saying or implying:

• no
• no we’re not women (but neither are we men)
• suggesting that somehow the question is unanswerable in any simple way

And of course it goes without saying that some “trans women” do claim to be women.

“Just ask them!”

If only this could answer the question about whether “trans women” are in fact women! Yes, testimony that p is evidence that p. But the testimony here is conflicting. Byrne comments,

If the main reason for [thinking that trans women are women] is the testimony of trans women themselves, then this is decidedly unimpressive.

It’s up to the proponents of TW to do better, but it remains to be seen if they can.