
This quote has been attributed to Mark Twain, but the attribution cannot be verified. The quote should not be regarded as authentic. — Twainquotes http://www.twainquotes.com/Discovery.html
Actually from the 1990 book P. S. I Love You' https://books.google.com/books?id=5OORXU6rlGIC&q=bowlines#v=onepage&q=bowlines&f=false' by H. Jackson Brown.
Misattributed