Thomas Jefferson wrote on August 10, 1787 a letter to his nephew Peter Carr containing number of interesting bits of advice regarding the young man’s education, including:
3. Moral Philosophy. . . . The moral sense, or conscience, is as much a part of man as his leg or arm. It is given to all human beings in a stronger or weaker degree, as force of members is given them in a greater or less degree. It may be strengthened by exercise, as may any particular limb of the body. This sense is submitted indeed in some degree to the guidance of reason; but it is a small stock which is required for this: even a less one than what we call common sense. State a moral case to a ploughman & a professor. The former will decide it as well, & often better than the latter, because he has not been led astray by artificial rules.
4. Religion. . . . Fix reason firmly in her seat, and call to her tribunal every fact, every opinion. Question with boldness even the existence of a god; because, if there be one, he must more approve of the homage of reason, than that of blindfolded fear. . . . Do not be frightened from this inquiry by any fear of it’s consequences. If it ends in a belief that there is no god, you will find incitements to virtue in the comfort & pleasantness you feel in it’s exercise, and the love of others which it will procure you.
5. Travelling. This makes men wiser, but less happy. When men of sober age travel, they gather knoledge which they may apply usefully for their country, but they are subject ever after to recollections mixed with regret, their affections are weakened by being extended over more objects, & they learn new habits which cannot be gratified when they return home. Young men who travel are exposed to all these inconveniences in a higher degree, to others still more serious, and do not acquire that wisdom for which a previous foundation is requisite by repeated & just observations at home.