ScrollingLeaves - "It seems surprising that to “know” you have a cut and are bleeding is not understood as a material ‘fact’ so much as a belief you have a cut. What about giving birth? A random experience on an equal footing with someone’s belief they are a woman trapped in a man’s body?"
Going back to your original point:
"I think it is a shame that the idea that sex is a fact was legally judged to be a belief in the Maya Forstater case, even though it was expedient and it is great that she won"
Maya's case did not relate to the protected characteristic of Disability (she had a cut and was bleeding or was delusional and believed she had a cut and was bleeding or because her employer was delusional, or misinformed, and believed she had a cut and was bleeding).
Neither did it relate to the protected characteristic of Pregnancy and Maternity.
Philosophical discussions are interesting if you have got the time and inclination. However, what we are dealing with is Legislation as currently enacted and interpretations in case law and both are subject to change.
IANAL but I was a Union Rep and what was important was that I understood the current state of Employment Law.
Lawyers and courts are not equipped or required to undertake scientific inquiry when dealing with cases under the EA2010 relating to the protected characteristic of Religion and Philosophical Belief. They can make what are later determined to be perverse judgements, as in the ruling by the Tribunal that first heard Maya's case.
If Maya had not been able to Appeal that first ruling then it would have been bad news, legally and also personally for Maya, but it would not have changed anything about the biology of sexual reproduction and the state of scientific knowledge.
Some lawyers are dissatisfied with the Grainger criteria and have suggested alternative ways of protecting freedom of speech under Employment Law, eg.
LEGISLATING AGAINST SOFT ATTACKS ON FREE SPEECH: PART I – EMPLOYMENT
https://joe-chiffers.co.uk/legal-news/legislating-soft-attacks-free-speech-part-i-employment/
I have not got the time, inclination or qualifications to comment on the merits of that particular proposal.
The only point that I want to make if an alternative to the Grainger criteria were to be adopted, or the EA2010 was repealed, it would not change what anyone believes about biological sex or gender identity or the state of scientific knowledge.
IIRC it was once a "fact" that horses were impregnated by the wind.
If you ever want to plunge into the depths of despair about how we got to where we are now, read the debates in Parliament during the passage of the Gender Recognition Bill in 2003/04 and later the Equality Bill.
Again and again there are MPs and Peers who make plain or state outright that they do not know what they are talking about, what is intended by the Legisation or what it even means.