There is no better example of the baroque style of writing in philosophy than David Hume's A Treatise of Human Nature. Like the Hall of Mirrors at Versailles, a Handel Oratorio, or Lord Shaftesbury's Characteristics of Men, Manners, Opinions, Times, it is characterized by complexity, grandeur, and expansiveness. Published in three separate volumes in 1739 and 1740, it well represents the age in which it was written. Indeed, there is a striking contrast between the Treatise and the core writings of Hume's later philosophy – his Enquiry Concerning Human Understanding and his Enquiry Concerning the Principles of Morals, first published in 1748 and 1752 respectively – where, as he said, he cast his earlier ideas anew. By comparison with the Treatise, these philosophical writings are simple and elegant. There is a reason for this. Hume was profoundly disappointed by the reception of the Treatise, and judged that its failure lay more in the manner than the matter. He decided that “by care and art, and the avoiding of all unnecessary detail” he could throw more light on the subjects he dealt with in the earlier book.

Nevertheless, it is this irregular pearl, the Treatise of Human Nature, which has come to be regarded as Hume's great philosophical masterpiece and, indeed, among the greatest philosophical books ever written. It is a book which every serious student of philosophy is expected to read, and the philosophical struggles of its author, dramatically described in the famous skeptical Conclusion to Book 1, have come to represent the philosophical enterprise itself.