Certainty?Knowing And Skepticism

Since ancient Greece,for simple needs for security,human beings began to seek a certainty to settle down in this dangerous world.From the certainty of the external world to the certainty of the inner world,philosophers try to use different theories to certain the the world.But for the "certainty" itself,different philosophers give different understandings,and the philosophical system that is constructed is also different.In his later years,Wittgenstein do the "certainty" research in "On Certainty",mainly focused on the concept of "certainty" and clarify the distinction.Moreover,"know" and "doubt" are the concrete application he made in the interpretation of the concept of "certainty".On the basis of previous research,based on Wittgenstein's understanding of the concept of "certainty" and the discussion,I would pointed out that the certainty of the concept distinguish between subjective one and objective one,and as a demonstration to confute Moore's common sense theory and Skepticism.