Still, desire of advancement and resentment about the lieutenancy, though factors and indispensable factors in the cause of Iago’s action, are neither the principal nor the most characteristic factors.  To find these, let us return to our half-completed analysis of the character.  Let us remember especially the keen sense of superiority, the contempt of others, the sensitiveness to everything which wounds these feelings, the spite against goodness in men as a thing not only stupid but, both in its nature and by its success, contrary to Iago’s nature and irritating to his pride.  Let us remember in addition the annoyance of having always to play a part, the consciousness of exceptional but unused ingenuity and address, the enjoyment of action, and the absence of fear.  And let us ask what would be the greatest pleasure of such a man, and what the situation which might tempt him to abandon his habitual prudence and pursue this pleasure.  Hazlitt and Mr. Swinburne do not put this question, but the answer I proceed to give to it is in principle theirs.[115]

The most delightful thing to such a man would be something that gave an extreme satisfaction to his sense of power and superiority; and if it involved, secondly, the triumphant exertion of his abilities, and, thirdly, the excitement of danger, his delight would be consummated.  And the moment most dangerous to such a man would be one when his sense of superiority had met with an affront, so that its habitual craving was reinforced by resentment, while at the same time he saw an opportunity of satisfying it by subjecting to his will the very persons who had affronted it.  Now, this is the temptation that comes to Iago.  Othello’s eminence, Othello’s goodness, and his own dependence on Othello, must have been a perpetual annoyance to him.  At any time he would have enjoyed befooling and tormenting Othello.  Under ordinary circumstances he was restrained, chiefly by self-interest, in some slight degree perhaps by the faint pulsations of conscience or humanity.  But disappointment at the loss of the lieutenancy supplied the touch of lively resentment that was required to overcome these obstacles; and the prospect of satisfying the sense of power by mastering Othello through an intricate and hazardous intrigue now became irresistible.  Iago did not clearly understand what was moving his desire; though he tried to give himself reasons for his action, even those that had some reality made but a small part of the motive force; one may almost say they were no more than the turning of the handle which admits the driving power into the machine.  Only once does he appear to see something of the truth.  It is when he uses the phrase ’to plume up my will in double knavery.’