When one event continually follows after another, most people think that a connection between the two events makes the second event follow from the first. Hume challenged this belief in the first book of his Treatise on Human Nature and later in his Enquiry Concerning Human Understanding . He noted that although we do perceive the one event following the other, we do not perceive any necessary connection between the two. And according to his skeptical epistemology, we can only trust the knowledge that we acquire from our perceptions. Hume asserted that our idea of causation consists of little more than the expectation for certain events to result after other events that precede them:
The constitution of the Roman republic gave the whole legislative power to the people, without allowing a negative voice either to the nobility or consuls. This unbounded power they possessed in a collective, not in a representative body. The consequences were: When the people, by success and conquest, had become very numerous, and had spread themselves to a great distance from the capital, the city-tribes, though the most contemptible, carried almost every vote: They were, therefore, most cajoled by every one that affected popularity: They were supported in idleness by the general distribution of corn, and by particular bribes, which they received from almost every candidate: By this means, they became every day more licentious, and the Campus Martius was a perpetual scene of tumult and sedition: Armed slaves were introduced among these rascally citizens; so that the whole government fell into anarchy, and the greatest happiness, which the Romans could look for, was the despotic power of the C æ ae originally 'æ'; separated to make searching the text easier sars . Such are the effects of democracy without a representative.
Hume had been toying for some time with the notion of writing a history, but did not begin in earnest until he was put in charge of the sizable library of the Faculty of Advocates in Edinburgh in 1752. After a few words on the “rude and turbulent” ancient Britons and their appalling Druids, his six-volume History traces England’s story from the arrival of Caesar to the deposition of James II in 1688. The inhumane effects of religious zealotry are a recurring theme. Hume’s emphasis on the harms to which religion can all too easily lead did not please many clerics. Harris argues that Hume’s History should be reckoned as broadly philosophical because of its focus on general principles of social, economic, and political change rather than on the actions of individuals. It was sometimes judged—for instance by Dr. Johnson, who did not intend this as a compliment—to be similar to the histories of Voltaire.