As we begin a new year, it's worth reflecting on the paradoxical and frustrating nature of progress. Progress is often disappointing, because even when it indisputably occurs (as it often does), it spawns new problems or reveals that old problems were underestimated in their complexity or inertia.

Gains are forgotten and taken for granted. They become part of society's norms, no longer celebrated because their existence is assumed to be permanent. Meanwhile, younger generations focus attention and discontent on new disputes and conflicts, as if the earlier advances had never occurred.

Progress resembles a parabola: first, spurting ahead; then, slipping back. In 2017, the uproar over "sexual harassment" exemplified this cycle. A root cause, of course, was the massive entry of women, beginning in the 1960s and 1970s, into the paid labor market.