You can only find truth with logic if you have already found truth without it. (Gilbert Keith Chesterton)

All truth passes through three stages. First, it is ridiculed.Second, it is violently opposed. Third, it is accepted as beingself-evident. (Arthur Schopenhauer)

I find that the harder I work, the more luck I seem to have. (Thomas Jefferson)

Many a man’s reputation would not know his character if they met onthe street. (Elbert Hubbard)

Each problem that I solved became a rule which served afterwards to solve other problems. (Rene Descartes, Discours de la Methode)