“How do you know you're whether or not you can do something, unless you try?”
“You don't know if you can do it unless you try! :)”
“Whether you think you can do something or not, you're right”
“Can you imagine doing something in your life that will be fully satisfying and redeeming for your having tried to do it, whether you succeeded in it or failed, and that, correspondingly, would be fully shameful had you not tried to do it?”
“You never know how much you can do, until you try to do more than you can.”
“Don’t wait for other people to tell you whether you can do something. You can do something whenever you want.”