
“If you think you can you can, if you think you can't you're right!”
“If you think you can you can, if you think you can't you're right!”
“If you think you can, you can. If you think you can't, you're right.”
Variant: If you think you can, you can. And if you think you can not, you are right.
"On Monsieur Coué", Epigram in The Week-end Book (1928), p. 217.
Can't Not
Supposed Former Infatuation Junkie (1998)
Quoting her mother's statement after her son's birth, in I Know Why the Caged Bird Sings (1969)
“You can't think decently if you're not willing to hurt yourself”
Source: Born to Run: A Hidden Tribe, Superathletes, and the Greatest Race the World Has Never Seen