I have the same concern as Daniel Kokotajlo, but for a different reason.
Mr Malmesbury considers the gradual extinction of genders beyond 2, but he never mentions the injection of fertile new genders into the population through mutations.
In order to make the case convincing case for unique suitability of exactly two genders, we should look for reasons why systems with three or more genders would be unstable. Here is a hint: consider a third gender entering into an established species with two genders: one with a huge gametes, the other with tiny gametes. Where does the gamete size of the new entry fit in?
I have the same concern as Daniel Kokotajlo, but for a different reason.
Mr Malmesbury considers the gradual extinction of genders beyond 2, but he never mentions the injection of fertile new genders into the population through mutations.
In order to make the case convincing case for unique suitability of exactly two genders, we should look for reasons why systems with three or more genders would be unstable. Here is a hint: consider a third gender entering into an established species with two genders: one with a huge gametes, the other with tiny gametes. Where does the gamete size of the new entry fit in?