Date: 1690, 1694, 1695, 1700, 1706

"But though we have, here and there, a little of this clear light, some sparks of bright knowledge; yet the greatest part of our ideas are such, that we cannot discern their agreement or disagreement by an immediate comparing them."

— Locke, John (1632-1704)

Date: 1761

"It is not the soft power of humanity, it is not that feeble spark of benevolence which Nature has lighted up in the human heart, that is thus capable of counteracting the strongest impluses of self-love."

— Smith, Adam (1723-1790)