As for the search for truth, I know from my own painful searching, with its many blind alleys, how hard it is to take a reliable step, be it ever so small, towards the understanding of that which is truly significant.
A man who lies to himself, and believes his own lies becomes unable to recognize truth, either in himself or in anyone else, and he ends up losing respect for himself and for others. When he has no respect for anyone, he can no longer love, and, in order to divert himself, having no love in him, he yields to his impulses, indulges in the lowest forms of pleasure, and behaves in the end like an animal. And it all comes from lying - lying to others and to yourself.
Something might be true while being harmful and dangerous in the highest degree. Indeed, it might be a basic characteristic of existence that those who know it completely would perish, in which case the strength of a spirit should be measured according to how much of the 'truth' one could still barely endure- or to put it more clearly, to what degree one would require it to be thinned down, shrouded, sweetened, blunted, falsified.