This article attempts to explore ancient Chinese philosophical thought by analyzing how pioneering Chinese thinkers made judgments and inferences,and compares it to ancient Greek philosophy.It first addresses the starting-point and the object of cognition in Chinese ancient philosophy,then analyses how early thinkers construed definition and proposition,and finally discusses how they made inferences on the basis of definition and proposition.It points out that categorization is an important methodology in ancient Chinese philosophy,and that rectification of names and the doctrine of the mean are key criteria in making judgments.