I THINK it proper to inform the public, that tho' this be a third volume of the Treatise of Human Nature, yet 'tis in some measure independent of the other two, and requires not that the reader shou'd enter into all the abstract reasonings contain'd in them. I am hopeful it may be understood by ordinary readers, with as little attention as is usually given to any books of reasoning. It must only be observ'd, that I continue to make use of the terms, impressions and ideas, in the same sense as formerly; and that by impressions I mean our stronger perceptions, such as our sensations, affections and sentiments; and by ideas the fainter perceptions, or the copies of these in the memory and imagination.