Richard Feynman
Theoretical physicist; Nobel laureate in Physics, 1965
So I wish to you—I have no more time, so I have just one wish for you—the good luck to be somewhere where you are free to maintain the kind of integrity I have described, and where you do not feel forced by a need to maintain your position in the organization, or financial support, or so on, to lose your integrity. May you have that freedom. May I also give you one last bit of advice: Never say that you'll give a talk unless you know clearly what you're going to talk about and more or less what you're going to say.
Recorded Caltech commencement address, Pasadena, California, Caltech Engineering and Science (Caltech Library archive), 1 June 1974 source ↗