All intelligent thoughts have already been thought what is necessary is only to try to think them again.

Originality is not the only thing worth having. An idea you have read stays a rumour until you work it out yourself, and that working out is what turns it into something usable under pressure. Plenty of true things sit inert in people’s heads because they were accepted rather than thought.

Take one belief you hold because somebody credible said it and try rebuilding it from the ground. Ask where you would look for evidence and what would change your mind. If it survives, it is yours now. If it does not, you have learned something more useful than a slogan.