Man is the measure of all things, of the existence of the things that are, and the non-existence of the things that are not.

Man is the measure of all things, of the existence of the things that are, and the non-existence of the things that are not.

人是衡量一切事物的尺度，衡量存在的事物的存在，衡量不存在的事物的不存在。

-- Protagoras 普罗泰戈拉