The article examines S.L. Frank's approaches to problematics of social forms in two relatively independent perspectives – in the perspective of Frank's critique of G. Simmel's formal sociology and in the perspective of his own philosophical constructions of social form. Accordingly, the article addresses two theoretical issues. The first is to clarify the reasons for Frank's negative evaluation of Simmel's formal project. The most plausible reasons are three: Frank's own psychological attitudes, not overcome by the time he wrote “The Essence of Sociology”; a critical appraisal of sociology's theoretical and cognitive possibilities and a desire to remove complex philosophical and cognitive problems from its field; the ambiguity of Simmel's concept of "social form" and the fruitlessness of its interpretation, in which it is reduced to universal one-dimensional axial parameters of interactions. The second theoretical task of the article is to clarify the place and meaning of the category "social form" in Frank's own constructions. It is shown that this category embodies the idea of ontological primacy of society, fundamental for his social philosophy. Social form is understood in it as a realization of "objective living idea", which has trans-psychic nature and is ontologically presupposed to interacting people, but requires them to actively participate in its implementation.