Gongsun Longzi (ch. 公孫龍子; pinyingong1sun1long2zi3) is a noted member of the Logicians school in Chinese philosophy, who lived during the Warring States Period. His most famous work is called 白馬非馬 (bai2ma3fei1ma3), literally "A white horse is not a horse", and is structured as conversation between two parties, with one party proclaiming truth in the statement and the other questioning. The argument plays upon the dual semantic meanings of informal language, in particular the dual interpretations of 'is', being either:
"Is a member of the class entitled (x)"
"Is identical to concept (x)"
Thus a white horse is not a horse, because the concept of a white horse is not the same as the concept of a horse.
