Well Objectivists may hold to that view if they like. It is unhistorical regardless.
As for wanting to know the "physical nature of man ... ask a scientist" — but what if I want to know what MAN is, not just his physical nature? He is obviously much, much more than science alone even has the methods or competence to address. To "reduce" him to what science can study strips him of what makes him truly human.
My own experience is that scientists would rather not get involved in ontological issues at all, because ontology smacks of philosophy, and thus is unacceptably subjective. (Don't forget, the scientific method claims to be wholly "objective.")
The fact is, both ontology and epistemology are major disciplines in philosophy and always have been. As it turns out, I've been doing a little thinking on these subjects recently, and even drew a picture:
And of course I recognize the Law of Identity as being Aristotelian logic! You don't have to explain it to me. But what A = A is, is a statement about a logical relation. It has nothing to say about the actual nature of A. One can posit the relation; but that doesn't tell you anything about WHAT is doing the "relating." How can one say one has any real knowledge of A from merely considering the relation A = A? Arguably, one can't.
Here's another little picture I drew that is in many respects similar to the one above:
If there is no correspondence between the natural world and an "equivalent orderliness of the Self," the observer of the natural world runs the risk of being misled about the nature of reality.
I merely mention this, because Ayn Rand evidently detested Plato. As much as she loved his student Aristotle, she condemned possibly the greatest psychologist (i.e., someone who deals with the order of the personal self) of all time as a "socialist." (You just can't make this stuff up.) And then she got some kind of strange notion that Aristotle "turned on" his teacher — because HE was an honest man and proto-objectivist, while Plato was a mystical moron and professional cadger.
This evidently being Rand's view, I just do not regard her as a serious thinker at all. Sorry.