墨子,小取
夫辯者,將以明是非之分…
Now disputation is for the
sake of making clear distinction between what is and
what is not.
{{Based on this passage, I think by shì and fēi Mo Zi means "what is really the case and what is not the case." So these terms should apply to individual propositions. Rán and bù rán, on the other hand, apply to compound sentences formed by the use of logical terms such as "if... then...." }}
The ways things are have their reasons. The way things are may be the same without the reasons for their being that way also being the same.
Now things are such that people make statements about things that do happen and the implications they postulate on that basis are held to be valid, or people make statements about things that do happen but the implications they postulate on that basis are held not to be valid, or the statements they use involve cases that do not occur and the implications they make about them are held to be valid.
•Commentary: Examples of these three classes, shì ér rán, shì ér bù rán, and bú shì er rán, are:
shì ér rán: "If the north pole is cold, then food left outside at night there will freeze." Ordinary people will accept this statement.
shì ér bù rán: "If Al Capone was a gangster, then Al Capone was human." Ordinary people will not accept this statement. (They may believe that murder is bad but execution is o.k.)
bú shì er rán: "If you do not complete your education all the way through medical school, then you will not become a physician." Ordinary people will accept this statement.
Note that the author of the Xiaoqu chapter may be simply describing how people in general handle these three kinds of statements. Why should the Mohists, who believe in "universal love," are pacifistic, and are demonstrably good logicians, not accept judgments such as, "If Goliath is a Hittite, then Goliath is a human being"? Non-Mohists may want to deny love to Goliath, even if the Mohists have convinced them of the validity of the principle of "universal love," by arguing that Goliath is not human. The Hittites in general, being the enemy, are not human. So there! The denial of human status to members of enemy nations at war is a common occurrence throughout human history. To avoid giving up many practical and important applications of their principle of universal love, applications that among other things argue against warfare, the Mohists would need to refute the non-Mohist or anti-Mohist argument.
Many modern philosophers would argue that the statement that "Al Capone was human" follows directly from the information that "Al Capone was a gangster" since "gangster" is defined as being one kind of human being.