David Hume 2

This is his epistemology and metaphysics

In a revolutionary step in the history of philosophy, Hume rejected the basic idea of causation, maintaining that “reason can never show us the connexion of one object with another, tho' aided by experience, and the observation of their conjunction in all past instances. When the mind, therefore, passes from the idea or impression of one object to the idea or belief of another, it is not determined by reason, but by certain principles, which associate together the ideas of these objects and unite them in the imagination.” Hume's rejection of causation implies a rejection of scientific laws, which are based on the general premise that one event necessarily causes another and predictably always will. According to Hume's philosophy, therefore, knowledge of matters of fact is impossible, although as a practical matter he freely acknowledged that people had to think in terms of cause and effect, and had to assume the validity of their perceptions, or they would go mad. He also admitted the possibility of knowledge of the relationships among ideas, such as the relationships of numbers in mathematics. Hume's skeptical approach also denied the existence both of the spiritual substance postulated by Berkeley and of Locke's “material substance.” Going further, Hume denied the existence of the individual self, maintaining that because people do not have a constant perception of themselves as distinct entities, they “are nothing but a bundle or collection of different perceptions.”
From Microsoft ® Encarta ® 2007. © 1993-2006 Microsoft Corporation. All rights reserved.

The wikipedia article I linked yesterday seem to be a good compliment to this. Although, I'm no longer certain that the Wiki author is right when he asserts that Hume can't possibly literally mean that a person is nothing but "a bundle or collection of different perceptions." After reading a little of Hume (and beginning to read actual Hume again and not just encyclopedia articles) I'm not sure I agree. The idea sounds very similar to the Buddhists idea of "No self."

-"Be a philosopher; but, amidst all your philosophy, be still a man." - Hume