By Dr. Blair's means, I have been favoured with the perusal of your performance, which I have read with great pleasure and attention. It is certainly very rare that a piece so deeply philosophical is wrote with so much spirit, and affords so much entertainment to the reader; though I must still regret the disadvantages under which I read it, as I never had the whole performance at once before me, and could not be able fully to compare one part with another. To this reason, chiefly, I ascribed some obscurities, which, in spite of your short analysis, or abstract, still seem to hang over your system; for I must do you the justice to own that, when I enter into your ideas, no man appears to express himself with greater perspicuity than you do; a talent which, above all others, is requisite in that species of literature which you have cultivated. There are some objections, which I would willingly propose, to the chapter "Of sight," did I not suspect that they proceed from my not sufficiently understanding it; and I am the more confirmed in this suspicion, as Dr. Blair tells me that the former objections I made, had been derived chiefly from that cause. I shall therefore forbear till the whole can be before me, and shall not at present propose any further difficulties to your reasonings. I shall only say that, if you have been able to clear up these abstruse and important subjects, instead of being mortified, I shall be so vain as to pretend to a share of the praise; and shall think that my errors, by having at least some coherence, had led you to make a more strict review of my principles, which were the common ones, and to perceive their futility. As I was desirous to be of some use to you, I kept a watchful eye all along over your style; but it is really so correct, and so good English, that I found not any thing worth the remarking. There is only one passage in this chapter, where you make use of the phrase, _hinder to do_, instead of _hinder from doing_, which is the English one; but I could not find the passage when I sought for it. You may judge how unexceptionable the whole appeared to me, when I could remark so small a blemish. I beg my compliments to my friendly adversaries, Dr. Campbell, and Dr. Gerard, and also to Dr. Gregory, whom I suspect to be of the same disposition, though he has not openly declared himself such.[154:1] This letter called forth the following answer, valuable as an acknowledgment of the services which the Scottish school of philosophy owed to Hume. DR. REID _to_ HUME. _King's College, 18th March, 1763._