No one person can be sane. It is always a judgment passed by someone else. And yet, given that each of us is at least in part unknowable to the other, it is a judgment to that extent passed on a set of representations. So....is sanity a pretense? One cannot cultivate sanity any more than one can cultivate madness. Sanity is not an act of will. As already said, it is an observation made about a set of representations under a set of conditions. Is that person's response to a circumstance sane or insane? There are too many variables at play in the circumstances of sanity to be subjected to formula or defined. Sanity is "x", including the quotation marks...
Sanity is the sleight-of-hand of consciousness. It is a mirror that cannot be seen, a whisper that cannot be heard. It is about us. Better, it is the sense of the mirror that cannot be seen, the rumor of a whisper that cannot be heard. Sanity is linked to the uncanny the way hope is linked to despair or belief to doubt. Sanity remarks that all the pieces do not fit, that there is inconsistency and irrationality. This remark posits the vantage point of the imagined self, of the illusion of normality, of coherence, of self. Sanity is this hope for the other, this desire that the signs cohere into sensible meaning.
The sensation of rejection, emanating from a communication that seeks but does not find an audience, that is not contested but rejected as nonsense is a dreadful disorientation. One's only topics are subjectivity and reality. One's only recourses upon rejection are despair or a hardening of autonomous conviction. Insanity.