New Dictionary of the History of Ideas | 2005 | Laursen, John | Copyright
Skepticism is both a generalized sense of doubt and disbelief as expressed in everyday language and an identifiable school of thought in the history of ideas. In its most general sense it refers to uncertainty, doubt, disbelief, suspension of judgment, and rejection of knowledge. It is characterized by its opposition to dogmatism, which claims to know reality and the truth.
As a philosophical tradition skepticism is best understood as the product of two movements in ancient Greek philosophy.
Academic skepticism can be attributed to Socrates and to Plato's successors at the Academy in Athens (fifth century to second century b.c.e.), and Pyrrhonism can be traced back to Pyrrho of Ellis (c. 365–275 b.c.e.). Elements of skepticism can be found in many other schools of ancient Greek philosophy, from Heraclitus to the Cyrenaics and the Cynics.
There are also analogies to ancient Greek and Roman skepticism in ancient Chinese, Persian, Arabic, and Indian philosophy, but they did not have the impact on modern thinking that the Mediterranean skepticisms did.