Both Hobbes and Locke came from families of West Country clothiers, and Bacon was the grandson of a sheep-reeve (a chief shepherd). All three family stories tell us something not only about the importance of wool in the English economy but also about the role of education in stimulating social mobility during the sixteenth and seventeenth centuries. Bacon's father, thanks to his studies at Cambridge, was able to become a prominent lawyer and marry into the aristocracy. Locke's father was also trained as a lawyer, although he remained a humble country attorney; thanks to his own education at Oxford, Locke was able to pursue a career that included diplomatic work, secretarial assistance to a rich politician, and, eventually, a well-paid government administrative post. Of the careers of these three philosophers, Hobbes's was certainly the least adventurous. But it too would not have been possible without his education at Oxford, which gave him his entrée to the Cavendish family, with whom he was to spend most of his life. The expense of educating a son up to university level may have been a threshold over which the poorest in society could not cross; yet the threshold was set relatively low, and once it had been passed a wide range of possible careers opened up.
One career that did not exist during this period was that of a professional philosopher. Not only was philosophy not defined or demarcated as a discipline in the way that it is today (the term was used to include the whole range of physical sciences as well), but there was no professionalization of the subject. Some of those who wrote about philosophical matters, such as Henry More or Ralph Cudworth, may have been employed as academics. By publishing philosophical works, however, they were not exhibiting academic 'research' so much as entering a republic of letters that was inhabited equally by churchmen, physicians, noblemen, officers of state, schoolmasters, and even, in the case of Hobbes's friend Sir Kenelm Digby, a one-time amateur pirate. With the proliferation of printing houses in seventeenth-century England, it was not difficult to get published. The modern system of royalties did not exist, but the code of patronage ensured that a well-chosen