[the virtues] cannot exist without Prudence. A proof of this is that everyone, even at the present day, in defining Virtue, after saying what disposition it is [i.e. moral virtue] and specifying the things with which it is concerned, adds that it is a disposition determined by the right principle; and the right principle is the principle determined by Prudence.
Friendship with the upright, with the truthful and with the well informed is beneficial. Friendship with those who flatter, with those who are meek and who compromise with principles, and with those who talk cleverly is harmful.
Nature herself, as has been often said, requires that we should be able, not only to work well, but to use leisure well; for, as I must repeat once again, the first principle of all action is leisure. Both are required, but leisure is better than occupation and is its end.
Of course, we will face fear, experience ridicule, and meet opposition. Let us have the courage to defy the consensus, the courage to stand for principle. Courage, not compromise, brings the smile of God's approval.
The history of science can be viewed as the recasting of phenomena that were once thought to be accidents as phenomena that can be understood in terms of fundamental causes and principles.
Once you become aware of your own body and its movements, you will be surprised that you are not your body. This is something of a basic principle, that if you can watch something then you are not it. You are the watcher, not the watched. You are the observer, not the observed. How can you be both?