 Locke and Newton probably first met in 1689 (though the exact date is not known; Westfall 1980, p. 488; Rogers 1982, p. 219), and their main works were written independently of one another; Locke’s Essay,though published subsequently, was essentially complete by the time he read the Principia.  A noticeable intellectual affinity may nevertheless be seen in those works, and the opportunity for mutual influence followed as they established a friendship, exchanging views on a wide variety of subjects, not least certain unorthodox theological convictions (see Westfall 1980, 490–91).  The influence did not run in one direction alone; in a draft passage probably penned shortly after the Principia’s second edition, for example, Newton adopts a Lockean tone as he denies that any ideas are innate.[22] As for Newton’s influence upon Locke, the best known example concerns action at a distance, as noted below, though there are deeper questions about methodology.