What goals would you be setting for yourself if you knew you could not fail?

Robert H. Schuller (1926-2015) American televangelist, pastor, motivational speaker, author
You Can Become the Person You Want To Be, ch. 2 (1973)

Earliest version of this aphorism. Often attributed (without citation) to Eleanor Roosevelt. See here for more information. Variants:
  • "What would you attempt if you knew you could not fail?"
  • "If you knew you cold not fail, what would you try?"
  • "What great things would you attempt if you knew you could not fail?"