From Alexander Pope’s Epistle to Bathurst (On the use of Riches) – lines 153-160 in the Twickenham edition:
“All this is madness,” cries a sober sage:
“But who, my friend, has Reason in his rage?
The ruling Passion, be it what it will,
The ruling Passion conquers Reason still.’
Less mad the wildest whimsy we can frame,
Than ev’n that Passion, if it has no aim;
For tho’ such motives Folly you may call,
The Folly’s greater to have none at all.
The last lines are reminiscent of Rochefoucauld’s Maxime CCIX:
Qui vit sans folie n’est pas si sage qu’il croit
He who lives without folly is not as wise as he believes
Folie, which I’ve rendered to be in accord with Pope, never makes the crossing intact. But in Rochefoucauld it generally carries a sense far closer to passion than to madness. One could almost say hobbyhorse.