Once a philosopher; twice a pervert.

The line appears as the punchline to a bawdy anecdote: after agreeing once to a sexual “experiment” (often framed as an orgy or homosexual encounter) and being invited or urged to repeat it, the speaker declines, implying that doing it once can be excused as curiosity but repeating it signals a settled inclination.

It draws a sharp distinction between a one-time transgression explained as intellectual curiosity and a second time that would indicate genuine appetite or identity; the humor relies on the speaker preserving a self-image of rational detachment by refusing repetition.

Once a philosopher; twice a pervert!

Once a philosopher: twice a sodomite!

Once, a philosopher; twice, a beast.

Once a philosopher, twice a pederast.

Once, a philosopher. Twice, a degenerate.

Une fois, c’est être philosophe ; deux fois, c’est être pédéraste.