Famous quotes containing the words theoretical and/or proof:
“There are theoretical reformers at all times, and all the world over, living on anticipation.”
—Henry David Thoreau (1817–1862)
“There are some persons in this world, who, unable to give better proof of being wise, take a strange delight in showing what they think they have sagaciously read in mankind by uncharitable suspicions of them.”
—Herman Melville (1819–1891)