[mckern]

Did you read this piece in good faith? I don’t see the authors having the blind spot you claim they have.

They made their case for a gametic definition of sex by explaining how the other definitions you’ve proposed are downstream of it. Along the way, they also explained how the gametic definition provides a certain generality that explains a lot of phenomena, both within and across species. As such, it seems they did make a solid case for the gametic definition of sex. Given that the definitions you favor are subsumed under theirs, why should they acknowledge yours?

While I acknowledge that the definitions you proposed could be useful in other areas of biology in an operational sense, that doesn’t make them the right definitions for describing and explaining what’s true about reality. This is akin to classical mechanics—it’s wrong, but the fact that it’s a good approximation of reality for many engineering use cases means it’s still useful. Again, wrong or incomplete as an explanation for aspects of reality, but still useful for the task at hand. The authors are evolutionary biologists, they care about the definition that best describes and explains a certain aspect of reality. A developmental biologist or a doctor might use your definitions because they’re good enough approximations that simplify the task at hand.

Furthermore, what makes you think they wouldn’t change their mind about the number of sexes if you were able to present the existence of a third gamete? Their definition permits that. In fact, they were explicit in stating that nature doesn’t have to stick with two discrete gametes, but that’s what we’ve ended up with. They don’t take this result for granted either, citing both observations and mathematical models to explain why we end up with two gametes. Why there are two gametes, no more, no less, is an open question. They explicitly quoted Ronald Fisher on this. That alone should tell you evolutionary biologists don’t take the binary for granted, which makes your accusation that they’re biased by “common sense” rather suspect.

You go on to grant that their definition could account for a hermaphrodite as a third sex, then accuse them of bias for their supposed unwillingness to do so. You also fault them for failing to account for sterility. All of this stems from your failure to understand the gametic definition of sex. If you did, three things should be apparent. First, the existence of a third gamete doesn’t imply that such an organism is a hermaphrodite. Second, a hermaphrodite fits well into their definition, being an organism with the floor-plan to produce both gametes. Third, the gametic definition is concerned with which floor-plan(s) an organism is instantiated with, not whether they can actually produce the corresponding gametes. Accusations should come only after a sincere effort to understand the other side. The ones you’ve made suggest a poor understanding of their points, not flaws in the points themselves. You accused them of being ideologues, but your misunderstanding here makes me question what’s actually going on; is the article too challenging for you, or are you the ideologue acting in bad faith?

Out of respect, I’m inclined to think you’re acting in bad faith here, and your subsequent accusations follow the same pattern. As such, rather than engaging further, I hope my comment helps signal to others that your response is woefully unreliable and that they should read the article directly instead.