2.  “We laugh if our attention is diverted to the physical in a person when it is the moral that is in question,” is a law we laid down in the first part of this work.  Let us apply it to language.  Most words might be said to have a physical and a moral meaning, according as they are interpreted literally or figuratively.  Every word, indeed, begins by denoting a concrete object or a material action; but by degrees the meaning of the word is refined into an abstract relation or a pure idea.  If, then, the above law holds good here, it should be stated as follows:  “A comic effect is obtained whenever we pretend to take literally an expression which was used figuratively”; or, “Once our attention is fixed on the material aspect of a metaphor, the idea expressed becomes comic.”

In the phrase, “Tous les arts sont freres” (all the arts are brothers), the word “frere” (brother) is used metaphorically to indicate a more or less striking resemblance.  The word is so often used in this way, that when we hear it we do not think of the concrete, the material connection implied in every relationship.  We should notice it more if we were told that “Tous les arts sont cousins,” for the word “cousin” is not so often employed in a figurative sense; that is why the word here already assumes a slight tinge of the comic.  But let us go further still, and suppose that our attention is attracted to the material side of the metaphor by the choice of a relationship which is incompatible with the gender of the two words composing the metaphorical expression:  we get a laughable result.  Such is the well-known saying, also attributed to M. Prudhomme, “Tous les arts (masculine) sont soeurs (feminine).”  “He is always running after a joke,” was said in Boufflers’ presence regarding a very conceited fellow.  Had Boufflers replied, “He won’t catch it,” that would have been the beginning of a witty saying, though nothing more than the beginning, for the word “catch” is interpreted figuratively almost as often as the word “run”; nor does it compel us more strongly than the latter to materialise the image of two runners, the one at the heels of the other.  In order that the rejoinder may appear to be a thoroughly witty one, we must borrow from the language of sport an expression so vivid and concrete that we cannot refrain from witnessing the race in good earnest.  This is what Boufflers does when he retorts, “I’ll back the joke!”

We said that wit often consists in extending the idea of one’s interlocutor to the point of making him express the opposite of what he thinks and getting him, so to say, entrapt by his own words.  We must now add that this trap is almost always some metaphor or comparison the concrete aspect of which is turned against him.  You may remember the dialogue between a mother and her son in the Faux Bonshommes:  “My dear boy, gambling on ’Change is very risky.  You win one day and lose the next.”—­“Well, then, I will gamble only every other day.”  In the same play too we find the following edifying conversation between two company-promoters:  “Is this a very honourable thing we are doing?  These unfortunate shareholders, you see, we are taking the money out of their very pockets....”—­“Well, out of what do you expect us to take it?”