“Whatever the mind of man can conceive and believe, it can achieve.”

Part 6 "Beyond System — The Ultimate Source of Jeet Kune Do"
Jeet Kune Do (1997)

Similar to a quote by Jesse Jackson, which is in turn a modification of a quote by Napoleon Hill: "Whatever the mind of man can conceive and believe, it can achieve."
Misattributed
Source: The Soul of a Butterfly: Reflections on Life's Journey

As quoted in Self-Motivation Through Risk Taking! : Are You Leading Or Do You Wither with Problems? (2005) by M. Nadarajan Munisamy

As quoted in OpenGL Shading Language (2006) by Randi J. Rost, p. 411

Speech at Anderson College in Anderson, Indiana (4 March 1979), quoted in Psychology Through the Eyes of Faith (1987) by David G. Myers and Malcolm A. Jeeves. The first sentence is a modification of a quote by Napoleon Hill: "Whatever the mind of man can conceive and believe, it can achieve."

Source: Total Recall: My Unbelievably True Life Story

On his facial scars which were the result of a childhood bout with Lupus, as quoted in "Seal: Still Crazy After All These Years" by Fiona Sturges in The Independent (11 October 2003)
Context: I've heard everything —that they were the result of ancient ritual induction into childhood that involved wrestling a wild boar, that I was viciously attacked by a gang. Someone even wrote that I was abducted by aliens who left me with a mark. You know, I really don't care. People can believe whatever they want to believe.