Wise in measure let each man be;
  but let him not wax too wise;
  for never the happiest of men is he
  who knows much of many things.

  Wise in measure should each man be;
  but let him not wax too wise;
  seldom a heart will sing with joy
  if the owner be all too wise.

  Wise in measure should each man be,
  but ne'er let him wax too wise:
  who looks not forward to learn his fate
  unburdened heart will bear.

That's Hávamál, from ~thousand years ago, give or take.