Not sure if this is the one you're talking about, but it rang a bell. I saw it in a Tony Robbins book most recently and then repeated in a book about TV addicti

Not sure if this is the one you're talking about, but it rang a bell. I saw it in a Tony Robbins book most recently and then repeated in a book about TV addiction. “First, you know, a new theory is attacked as absurd; then it is admitted to be true, but obvious and insignificant; finally it is seen to be so important that its adversaries claim that they themselves discovered it.” - William James "First, it is ridiculed. Second, it is violently opposed. Finally, it is accepted as self-evident." - Arthur Schopenhauer