If one has insufficient reasons for rejecting a dominant philosophical position but sufficient reasons to doubt that the dominant philosophical position is unproblematic, to what extent is one rationally justified in assuming that dominant philosophical position?
One should ask what role -- if any -- the dominance of the philosophical position has on one's decision to accept it. If the dominance of the philosophical theory is important, then it is possible that one is selecting a position for fear of disagreeing with others, especially those in authority. The anticipated consequences of not accepting the dominant theory are not necessarily relevant to whether or not the philosophical position itself merits acceptance. (Although, in reality, such acceptance -- or at least the appearance of acceptance in the eyes of others -- may have pragmatic benefits, such as allowing one to survive in a society where there are prisoners of conscience, and an official ideology imposed by the government).
Irving M. Copi classifies informal fallacies into two kinds. Those based on "irrelevance" and those based on "ambiguity". (Page 98) One fallacy he mentions that might be related to the fear involved in disagreeing with a dominant position is "appeal to authority" or "argumentum ad verecundiam'. (Pages 105-6)
So, one would not be rationally justified in accepting the dominant philosophical position, unless one discovered an adequate basis for accepting the full philosophical position. In the absence of such a basis, one would be rationally justified in accepting only some parts of the dominant philosophical position.
Copi, I. M. Introduction to Logic Sixth Edition. Macmillan. 1982.