Scottish philosopher David Hume is responsible for a body of work that represents the empiricist tradition in British philosophy. Hume's deep skepticism led him to conclude that, in essence, we cannot know with certainty that the external world actually exists (Gray 41). In this, the real world is unknowable. That said, we cannot know things for their intrinsic qualities, but rather must observe the phenomena that individual experiences provide. In Hume's Enquiry's: Concerning the Human Understanding and Concerning the Principles of Morals, he establishes the underpinnings of his empiricist philosophy, addressing the objects of human reason and the relation of cause and effect.
Hume's philosophical assumptions flow from a broad presupposition that philosophy is first and foremost an empirical science. For this, the experimental method is very useful to Hume, and he holds that all human beliefs, customs, and thoughts arise from experienceùwithout a connection to experience, our thoughts lack meaning and content. Naturally, then, Hume must explore the objects of human inquiry, which he describes as belonging to two groups: "Relations of Ideas and Matters of Fact" (Hume 25). Relations of ideas, according to Hume, concern "every affirmation which is either intuitively or demonstratively certain" (Hume 25). As such, mathematical propositions, "discoverable by the mere operation of thought" (Hume 26), will fall in this category. Matters of fact, on the other hand, cannot be ascertained the way that geometricians deduce the properties of a triangle. Matters of fact are, according to Hume, contingent upon a paradoxical property that establishes that "The contrary of every matter of fact is still possible" (Hume 26). By Hume's own reckoning, the idea that the sun will not rise tomorrow is "no less intelligible a proposition" (Hume 26) than the inverse (and received) idea that it will rise.
Hume later explores this concept...