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 to what extent the word dominant has on one's decision to accept the position. If the dominance of the philosophical theory is important then the reason one is accepting the position may be out of fear of disagreeing with others especially those in authority. This would be an irrelevant reason to accept the position.
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 that dominant philosophical position without also having the courage to note where one disagreed with it.
Copi, I. M. Introduction to Logic Sixth Edition. Macmillan. 1982.