This is obviously false as evolutionary theory has branched us for a reason, for efficient fulfillment of sexually divergent roles & tasks - changing brain structure is such obvious low hanging fruit for role specialization, dimorphic evolution would mandate differing gene expression.
In order to defend the OA you would have to invent a way to specialize at fulfilling a new biological role environment without using any of the tools available to evolution and just as well as if you did, ie differing regional brain size and connection densities - among thousands of other variables.
"Most brains are comprised of unique mosaics of features, some more common in females compared with males, some more common in males compared with females, and some common in both females and males. Our findings are robust across sample, age, type of MRI, and method of analysis..."
"Our results demonstrate that regardless of the cause of observed sex/gender differences in brain and behavior (nature or nurture), human brains cannot be categorized into two distinct classes: male brain/female brain."
If you take a random brain, you will not be able to tell if it is a female or a male brain, you can only assign probability to it. The same brain could be a female or a male brain, that is what it mean to be unable to create distinct classes.
I don’t know about what other studies say, but the study i am speaking about say that we can’t create distinct classes, which is synonymous to say that we can’t know if a random brain is a female or a male brain with enough certainty. (even if, on average, there are differences)
Even if we can't reliably distinguish between the two, they certainly fall along a Gaussian curve in terms of various traits. This is much the same with the polar and grizzly bear. They can mate with each other, and have a Gaussian curve of similar traits, but are still different species.
I don't disagree with the study, but I think they likely meant that we can't distinguish *with certainty*, rather than *at all*. As for the bear analogy, I realize it's flawed, but it really isn't a separate species, as far as definitions are concerned.
Ok, interesting, if it is that i was wrong all along.
If being able to distinguish between A and B with 99,9% of certainty doesn’t count as A and B being distinct classes, then it was pretty obvious from the start that man and woman brain would not be distinct classes.