The phrase "a certain rationale" is correct and usable in written English.
It can be used when referring to a specific reasoning or justification for a decision or action, without specifying what that rationale is.
Example: "The committee decided to approve the proposal based on a certain rationale that was not disclosed to the public."
Alternatives: "a specific reasoning" or "a particular justification."
Despite its sleazy reputation, payola has a certain rationale.
But there is a certain rationale to Pyongyang's moves.
Yet all of this presupposes a certain rationale: that at the ballot box Greeks will weigh their options, think logically and vote for the man who has rolled back on almost every pledge he has ever made.
It doesn't make this any more palatable, but it is given a certain rationale by Samantha Spiro's no-holds-barred Katherina, who knocks down walls with her fists and whose instinctive response to a prospective wooer is to kick him in the goolies.
When abstraction was in the forefront, when content was less confrontational and when edginess was more a question of style, there also would have been a certain rationale in linking the pioneering qualities of art with a corporation's image as an innovator in its industry.
So there's a certain rationale in funding already-approved proposals with the stimulus money and doing the more creative things with money from the ensuring budget cycles.
More understanding of the mechanism may lead to a more certain rationale for careful induction of NAbs and CTLs by vaccination, maybe potentially capable of synergistic HIV-1 control.
Uncertainties on relevant facts can be masked when not all arguments are regarded as pertinent, for example when a policy elite manages to frame a certain problem exclusively within an economic rationale.
The choice of the specific level at which to allocate a certain competence, regardless of its actual rationale, has implications for the relation between the agency's territorial jurisdiction and the scale of the activities that the specific competence foresees.
"We agonized for weeks prior to the meeting, stopped all work other than that related to the consultant meeting and pulled together presentations and rationale about why we do things a certain way".
Patrick Shin proposes a similar account in his discussion of equal protection, arguing that "to characterize an action as unequal treatment is to register a certain objection as to what, in view of its rationale, the action expresses" (2009: 170).
