The issue of social and physical sciences was really the prime issue of German philosophy which, it should be noted arose in the context of the sturm and drang, then the Romantic movement. Marx made a heroic effort to ride the two resulting streams in tandem. The problem is the issue of causality, required by science, and 'freedom' required for a live createur called man. How to reconcile the two? Kant had one approach, Hegel another, inventing a dialectical logic. Schopenhauer goes back to the issue of two levels, and in fact is closer to science than one might think. Marxism we should note rejects Hegel yet is crypto-Hegelian, and always in a kind of limbo.
The problem then with positivism is that it simply ignored the philosophical innovations and reverted to type. It is worth reading Wilson's book on Consilience to see just how unrepentant a positivist he is. Ethics is to be essentiallly discarded as a serious endeavor, even as fine words are overlaid on the selectionist accounts of altruism. If I agree with Wagar, it is because of the adamancy of the rejection of all other approaches and worse the failure to see that Darwinian accounts are hardly science.
I mention Wilson because this division of social and hard science is caught up in the Darwin debate. So let's not pretend that we have an evolutionary theory and then turn around and deny that on historical issues.
Thus in any case the question of science here is antinomous, as predicted by Kant in his dialectic. It is worth picking up a short summary version of Kant's critique, and looking at the section describing the dialectic. Everything turns on that merry go round, ad infinitum.
Hegel is some ways did a disservice here, although his experiment is of great interest, that is, he simply buried Kant. That's unfair. The diagnosis is there. But the biological sciences simply refuse to learn. So that's that. Fallacy reigns.
I say that we expect a reasonable history here, and scratch our heads all of a sudden when we wake up a moment to see that it is possible to be on the wrong track for two centuries, maybe forever.
So the issue is the antinomous character of the foundational issues of social science.
On a lighter note, I have a webpage on systems and the computer mouse. Who says social science and hard science can be combined? Look at the computer mouse, a 'system' consisting of a live agent and a mouse, this is the 'freedom necessity' syndrome again, neatly packaged in one.. http://eonix.8m.com/systems.htm