"SIR,--When I write you, I know not to whom I am addressing myself: I only know he is one who has done me a great deal of honour, and to whose civilities I am obliged. If we be strangers, I beg we may be acquainted, as soon as you think proper to discover yourself: if we be acquainted already, I beg we may be friends: if friends, I beg we may be more so. Our connexion with each other as men of letters, is greater than our difference as adhering to different sects or systems. Let us revive the happy times, when Atticus and Cassius the epicureans, Cicero the academic, and Brutus the stoic, could all of them live in unreserved friendship together, and were insensible to all those distinctions, except so far as they furnished agreeable matter to discourse and conversation. Perhaps you are a young man, and being full of those sublime ideas, which you have so well expressed, think there can be no virtue upon a more confined system. I am not an old one; but, being of a cool temperament, have always found, that more simple views were sufficient to make me act in a reasonable manner; νηθε, και μἑμνησο ἀπιστειν; in this faith have I lived, and hope to die. "Your civilities to me so much overbalance your severities, that I should be ungrateful to take notice of some expressions which, in the heat of composition, have dropped from your pen. I must only complain of you a little for ascribing to me the sentiments, which I have put into the mouth of the Sceptic in the "Dialogue." I have surely endeavoured to refute the sceptic, with all the force of which I am master; and my refutation must be allowed sincere, because drawn from the capital principles of my system. But you impute to me both the sentiments of the sceptic, and the sentiments of his antagonist, which I can never admit of. In every dialogue no more than one person can be supposed to represent the author. "Your severity on one head, that of chastity, is so great, and I am so little conscious of having given any just occasion to it, that it has afforded me a hint to form a conjecture, perhaps ill-grounded, concerning your person. "I hope to steal a little leisure from my other occupations, in order to defend my philosophy against your attacks. If I have occasion to give a new edition of the work, which you have honoured with an answer, I shall make great advantage of your remarks, and hope to obviate some of your criticisms. "Your style is elegant, and full of agreeable imagery. In some few places it does not fully come up to my ideas of purity and correctness. I suppose mine falls still further short of your ideas. In this respect, we may certainly be of use to each other. With regard to our philosophical systems, I suppose we are both so fixed, that there is no hope of any conversions betwixt us; and for my part, I doubt not but we shall both do as well to remain as we are. "I am, &c. "_Edinburgh, March 15, 1753._"