The renowned critic Harold Bloom calls Shakespeare's Macbeth "a tragedy of the imagination," contending that Macbeth and Lady Macbeth derive satisfaction in their wickedness. However, this satisfaction does not last as their imaginations rage out of control in suspicion, turmoil, and paranoia. Macbeth in his "vaulting ambition" must continue doing evil even though he greatly suffers from knowing that he does evil. After he kills Duncan, for instance, he then fears the witches' prophecy about Banquo and his descendents and then makes his murderous attacks upon Banquo and his son.
Likewise, the apparently coldly brutal Lady Macbeth is halted in her murderous path by conscience. Ironically, when she boldly urges Macbeth to slay Duncan and ridicules her husband for his twinges of conscience as he says "I am afraid to think what I have done" (2.2.65) by retorting, "A little water clears us of this deed" (2.2.85), like Dostoevsky's Raskolnikov, she does not consider that her own conscience will haunt her. Thus, by Act V she has gone mad from the disquiet of her guilt and kills herself. Macbeth, so consumed with raging ambition and lust for power that he is more concerned with preparing himself for battle in Dunsinane, does not even inquire how his wife has died when he is informed. Later however, even in his moral turpitude, he feels again the twinge of conscience,
My way of life
Is fall'n into the sear, the yellow leaf,
And that which should accompany old age,
As honor, love, obedience, troops of friends,
I must not look to have; but, in their stead,
Curses, not loud but deep, mouth-honor, breath,
Which the poor heart would fain deny and dare not. (5.3.25-31)
Unable to control their imaginations and consciences, Macbeth and Lady Macbeth are disquieted by the deeds that their raging ambition have wrought.