4. A good instance of a metaphorical argument drawn out is given by Mr. Mill:--'For instance, when Mr. Carlyle, rebuking the Byronic vein, says that "strength does not manifest itself in spasms, but in stout bearing of burdens;" the metaphor proves nothing, it is no argument, only an allusion to an argument; in no other way however could so much of argument be so completely suggested in so few words. The expression suggests a whole train of reasoning, which it would take many sentences to write out at length. As thus: Motions which are violent but brief, which lead to no end, and are not under the control of the will, are, in the physical body, more incident to a weak than to a strong constitution. If this be owing to a cause which equally operates in what relates to the mind, the same conclusion will told there likewise. But such is really the fact. For the body's liability to these sudden and uncontrollable motions arises from irritability, that is, unusual susceptibility of being moved out of its ordinary course by transient influences: which may equally be said of the mind. And this susceptibility, whether of mind or body, must arise from a weakness of the forces which maintain and carry on the ordinary action of the system. All this is conveyed in one short sentence. And since the causes are alike in the body and in the mind, the analogy is a just one, and the maxim holds of the one as much as of the other.'* * Logic, pp. 433-4, vol. 2. 5. A youth, named Evathlus, engaged with Protagoras to learn dialectics, and promised his tutor a large sum of money, _in case he gained the first cause he pleaded_, Evathlus, when fully instructed, refused to pay his instructor. Protagoras brought his action thus--'You must pay the money however the cause go, for if I gain you must pay in consequence of the sentence, as being cast in the cause; and if you gain it, you must pay in pursuance of our covenant.' 'Nay,' Evathlus retorts, 'which way soever the cause be decided, you will have nothing, for if I prevail, the sentence gives it that nothing is due: and if I lose, then there is nothing due by the covenant.' What should be the decision in this case?