One piece of advice.

Permit me, sir, to give you one piece of advice. Be not so positive; especially with regard to things which are neither easy nor necessary to be determined. When I was young I was sure of everything. In a few years, having been mistaken a thousand times, I was not half so sure of most things as I was before. At present, I am hardly sure of anything but what God has revealed to man.

--John Wesley (Reply to a letter signed "Philosophaster," addressed to him in the London Magazine of 1774, in London Magazine 1775, p. 26)