Skepticim refer to the philoophic poition holding that the poibility of knowledge i limited either becaue of the limitation of the mind or becaue of the inacceibility of it object. It i more looely ued to denote any quetioning attitude. Extreme kepticim hold that no knowledge i poible, but thi i logically untenable ince the tatement contradict itelf. During the Renaiance the influence of ancient kepticim wa reflected preeminently in the writing of the 16th-century French philoophical eayit Michel de Montaigne. The greatet exponent of modern kepticim wa the 18th-century Scottih empiricit philoopher David Hume. In hi Treatie of Human Nature and An Enquiry Concerning Human Undertanding , Hume quetion the poibility of demontrating the truth of belief about the external world, caual connection, future event, or uch metaphyical entitie a the oul and God. The 18th-century German philoopher Immanuel Kant, while attempting to overcome Hume kepticim, denied the poibility of knowing thing in themelve or of achieving metaphyical knowledge. In the 19th century, the German philoopher Friedrich Nietzche denied the poibility of complete objectivity, and thu of objective knowledge, in any field. The 20th-century American philoopher George Santayana, claiming to have taken Hume kepticim a tep further, maintained, in hi work Scepticim and Animal Faith , that belief in the exitence of anything, including oneelf, ret on a natural, but irrational impule. Element of kepticim may be found in other modern chool of philoophy, including pragmatim, analytic and linguitic philoophy, and exitentialim.[由www.hAozuowEn.com整理]