From the New York Review of Books, 28 October 2010:
If nature has made any one thing less susceptible than all others of exclusive property, it is the action of the thinking power called an idea…. He who receives an idea from me, receives instruction himself without lessening mine; as he who lights his taper at mine, receives light without darkening mine.
Jefferson (qtd. p. 4)
What another sees and tells you is not yours, but his.
Emerson (qtd. p. 25)