Aenesidemus (born 1st century bc, Knossos, Crete) was a philosopher and dialectician of the Greek Academy who revived the Pyrrhonian principle of “suspended judgment” (epoche) as a practical solution to the vexing and “insoluble” problem of knowledge. In his Pyrrhonian Discourses, Aenesidemus formulated 10 tropes in defense of Skepticism, four suggesting arguments that arise from the nature of the perceiver, two dealing with the thing perceived, and four concerning the relationship between the perceiver and the thing perceived.