Q. How do ethics and morals differ?
A. The distinction may be that ethics is the art of good conduct as defined by absolute standards, whilst morals are determined by society. What is moral is not always stable. It depends on what society finds acceptable at a given moment. What is ethical requires an external criterion, which in the case of religion is God.
Because immorality is not what it used to be; it became possible to speak of the New Morality. The most obvious example is the sexual revolution; society these days endorses or condones many things that were once regarded as unthinkable.
Judaism wonders how an act or attitude can be wrong yesterday, right today, and possibly wrong again tomorrow. It calls this flexibility hefker, “out of control” – i.e. anarchy. The Jewish view prefers fixed points with a fence around them (Avot 1:1) as a guard against infringement. Thus the rules of impermissible sexual conduct are protected by the notion of n’gi’ah, which literally means “touching” but in a wider sense warns us not to put ourselves into an erotic situation which could lead one across the line; and by the concept of tz’ni’ut, “modesty”, which denotes a general attitude of dignity in dress, speech and conduct. None of this implies that sex is in any way “dirty” but that it is holy and must not be cheapened.