128 JAMES CLERK MAXWELL. [CHAP. V. 



on Probabilities, with very grand props in it ; everything 

 original, but no signs of reading, I guess. It was all written 

 in a week. He has despaired of Optics. 12-1. Wilson, 

 after having fully explained his own opinions, has proceeded 

 to those of other great men : Plato, Aristotle, Stoics, Epicu- 

 reans. He shows that Plato's proof of the immortality of 

 the soul, from its immateriality, if it be a proof, proves its 

 pre-existence, the immortality of beasts and vegetables, and 

 why not transmigration ? (Do you remember how Raphael 

 tells Adam about meats and drinks in Paradise Lost?} 

 (Greek Iambics, if you please.) He quarrels with Aristotle's 

 doctrine of the Golden Mean, " a virtue is the mean between 

 two vices," not properly understanding the saying. He 

 chooses to consider it as a pocket rule to find virtue, which 

 it is not meant to be, but an apophthegm or maxim, or dark 

 saying, signifying that as a hill falls away on both sides of 

 the top, so a virtue at its maximum declines by excess or 

 defect (not of virtue but) of some variable quantity at the 

 disposal of the will. Thus, let it be a virtue to give alms 

 with your own money, then it is a greater virtue to pay 

 one's debts to the full. Now, a man has so much money : 

 the more alms he gives up to a certain point, the more 

 virtue. As soon as it becomes impossible to pay debts, the 

 virtue of solvency decreases faster than that of almsgiving 

 increases, so that the giving of money to the poor becomes 

 a vice, so that the variable is the sum given away, by 

 excess or defect of which virtue diminishes, say I ; so that 

 Wilson garbles Aristotle, but I bamboozle myself. I say 

 that some things are virtues, others are virtuous or generally 

 lead to virtue. Substitute goods for virtues, and it will be 

 more general : thus, Wisdom, Happiness, Virtue, are goods, 

 and cannot be in excess ; but Knowledge, Pleasure, and 

 what ? (please tell me, Is it Propriety, Obedience, or what is 

 it ?) lead to the other three, and are not so much goods as 

 tending to good ; whereas particular knowledges, pleasures, 

 and obediences may be in excess and lead to evils. I post- 

 pone the rest of my observations to my Collection of the 

 Metaphysical principles of Moral Philosophy founded on 



