The task of identifying the line between good and evil is like infinitesimal calculus. Mere intuitions are insufficient, which is why "going with the flow" so easily ends in evil. Many marriages fail this way, as sincerely innocent intentions to "make friends" or enjoy "a rich private life” all of a sudden become adulterous affairs or irrecoverable distances. To keep innocence from turning to guilt requires strict and formal tools, just as one cannot eyeball the derivative of a curve, but when it comes to good and evil the objects of analysis are typically difficult to measure. This is the genius of socially conservative Christian norms around sex and marriage, which are often seen as stupidly strict prohibitions, e.g. never having alone time with a member of the opposite sex. Secular cosmopolitans today laugh at this norm, but are the scoffers and mockers really doing so well? In the context of this particular example, marriage, one error on the side of adultery does more damage than several errors on the side of foregone other-sex friendship experiences. As a result, some educated cosmopolitans run around with many "friendships" and failed marriages, scoffing at the paranoia of Christian family values, although the latter include some superior, evolved formalities to deal with overly complex identification problems we are incapable of solving intuitively "in the moment." Whenever a fatal point on a map is hard to detect, it makes sense to prohibit any entrance into the smallest definable region around the undetectable point. Unconditional prohibition may be the most sophisticated rule in contexts where many hidden chutes toward the netherworld are known to exist, even if a sizable range of perfectly innocent and desirable experiences must be forgone.