This question is tantamount to asking whether we can possess knowledge of ourselves. That we can to some extent is trivial, despite the endeavor’s hurdles (many of which–ironically–the human study of psychology has revealed).
We have developed such successful sciences of physics and chemistry due perhaps to our advantage over their subject matter. This is that we have at least a greater degree of consciousness than do particles, waves, and elements.
It may be argued that human scientists have a greater consciousness of people than the average person does. If this is so, then the epistemology of social science is on somewhat comparable grounds to that of physics and chemistry.
However, it is quite probable that human scientists are not so different from laypeople as all people are from physical objects. This represents an asymmetry worth pausing on in answering this post’s question.