„[…]the simple-minded positivism that believes it has found a firm ground of certainty if it only excludes all mental phenomena from consideration and holds fast to observable facts.“

— Hannah Arendt
„I pass with relief from the tossing sea of Cause and Theory to the firm ground of Result and Fact.“
— Winston S. Churchill
„Our psychology is … a science of mere phenomena without any metaphysical implications. [It] Treats all metaphysical claims and assertions as mental phenomena, and regards them as statements about the mind and its structure.“
— C.G. Jung