(n.) The doctrine that no fact or principle can be certainly known; the tenet that all knowledge is uncertain; Pyrrohonism; universal doubt; the position that no fact or truth, however worthy of confidence, can be established on philosophical grounds; critical investigation or inquiry, as opposed to the positive assumption or assertion of certain principles.
SKEPTICISM
Meaning of SKEPTICISM in English
Webster's English dictionary. Английский словарь Webster. 2012