Locke's theory on certainty of knowledge

Certainty of knowledge is the central point of Lockes theory of knowledge. According to the principle of Experiencism, he thinks that both mental action of recognition and linguistic description of knowledge restrict certainty of knowledge. The original meaning of certainty is self_evidence or universality, but its essence is substantiality, thus certain knowledge can be gained with different degrees: intuitive, demonstrable and experimental knowledge. His theory on certainty of knowledge influences greatly the research into certainty in modern west.