He kneels and prays,
     And now I’ll do’t, and so he goes to heaven,
     And so am I reveng’d; that would be SCANN’D. 
     He kill’d my father, and for that,
     I, his sole son, send him to heaven. 
     Why this is reward, not revenge. 
     Up sword and know thou a more horrid time,
     When he is drunk, asleep, or in a rage.

He is the prince of philosophical speculators, and because he cannot have his revenge perfect, according to the most refined idea his wish can form, he misses it altogether.  So he scruples to trust the suggestions of the Ghost, contrives the scene of the play to have surer proof of his uncle’s guilt, and then rests satisfied with this confirmation of his suspicions, and the success of his experiment, instead of acting upon it.  Yet he is sensible of his own weakness, taxes himself with it, and tries to reason himself out of it: 

     How all occasions do inform against me,
     And spur my dull revenge!  What is a man,
     If his chief good and market of his time
     Be but to sleep and feed?  A beast; no more. 
     Sure he that made us with such large discourse,
     Looking before and after, gave us not
     That capability and god-like reason
     To rust in us unus’d:  now whether it be
     Bestial oblivion, or some craven scruple
     Of thinking too precisely on th’ event,—­
     A thought which quarter’d, hath but one part wisdom,
     And ever three parts coward;—­I do not know
     Why yet I live to say, this thing’s to do;
     Sith I have cause, and will, and strength, and means
     To do it.  Examples gross as earth excite me: 
     Witness this army of such mass and charge,
     Led by a delicate and tender prince,
     Whose spirit with divine ambition puff’d,
     Makes mouths at the invisible event,
     Exposing what is mortal and unsure
     To all that fortune, death, and danger dare,
     Even for an egg-shell.  ’Tis not to be great,
     Never to stir without great argument;
     But greatly to find quarrel in a straw,
     When honour’s at the stake.  How stand I then,
     That have a father kill’d, a mother stain’d,
     Excitements of my reason and my blood,
     And let all sleep, while to my shame I see
     The imminent death of twenty thousand men,
     That for a fantasy and trick of fame,
     Go to their graves like beds, fight for a plot
     Whereon the numbers cannot try the cause,
     Which is not tomb enough and continent
     To hide the slain?—­O, from this time forth,
     My thoughts be bloody or be nothing worth.

Still he does nothing; and this very speculation on his own infirmity only affords him another occasion for indulging it.  It is not for any want of attachment to his father or abhorrence of his murder that Hamlet is thus dilatory, but it is more to his taste to indulge his imagination in reflecting upon the enormity of the crime and refining on his schemes of vengeance, than to put them into immediate practice.  His ruling passion is to think, not to act:  and any vague pretence that flatters this propensity instantly diverts him from his previous purposes.