Epicurus (341—271 B.C.E.) Epicurus is one of the major philosophers in the Hellenistic period, the three centuries following the death of Alexander the Great in 323 B.C.E. (and of Aristotle in 322 B.C.E.). Epicurus developed an unsparingly materialistic metaphysics, empiricist epistemology, and hedonistic ethics. Epicurus taught that the basic constituents of the world are atoms, uncuttable bits of matter, flying through empty space, and he

Introspection Introspection is the process by which someone comes to form beliefs about her own mental states. We might form the belief that someone else is happy on the basis of perception – for example, by perceiving her behavior. But a person typically does not have to observe her own behavior in order to determine whether she is happy. Rather, one makes this determination by

Evidence The concept of evidence is crucial to epistemology and the philosophy of science. In epistemology, evidence is often taken to be relevant to justified belief, where the latter, in turn, is typically thought to be necessary for knowledge. Arguably, then, an understanding of evidence is vital for appreciating the two dominant objects of epistemological concern, namely, knowledge and justified belief. In the philosophy of

Ethics and Self-Deception Self-deception has captured the interest of philosophers, psychologists, and other students of human nature. Philosophers of mind and action have worked towards developing an account of self-deception and, in so doing, an explanation of its possibility. They have asked questions concerning the origin and structure of self-deception: How is self-deception possible? Do self-deceivers hold contradictory beliefs? And do they intentionally bring about

Gottfried Wilhelm Leibniz (1646-1716) Widely hailed as a universal genius, Gottfried Wilhelm Leibniz was one of the most important thinkers of the late 17th and early 18th centuries. A polymath and one of the founders of calculus, Leibniz is best known philosophically for his metaphysical idealism; his theory that reality is composed of spiritual, non-interacting “monads,” and his oft-ridiculed thesis that we live in the

Protagoras (fl. 5th c. B.C.E.) Protagoras of Abdera was one of several fifth century Greek thinkers (including also Gorgias, Hippias, and Prodicus) collectively known as the Older Sophists, a group of traveling teachers or intellectuals who were experts in rhetoric (the science of oratory) and related subjects. Protagoras is known primarily for three claims (1) that man is the measure of all things (which is