Thinking too precisely on the event
Hamlet:
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't.
Having just encountered a Norwegian force on its way to contest "a little patch of ground" in Poland, the Prince of Denmark once again upbraids himself for being unable to act decisively. Commanded by his father's ghost to avenge his murder, Hamlet has as yet been unable to do the deed.
Hamlet's self-appraisals here echo earlier sentiments—that "conscience does make cowards of us all" and that "the native hue of resolution/ Is sicklied o'er with the pale cast of thought" [see TO BE, OR NOT TO BE, THAT IS THE QUESTION]. He spoke then of the fear of death; here, he speaks of "thinking" in general, the "precise" lingering over objections, reappraisals, calculations, implications, etc., to the point where action is stifled and opportunities missed. Hamlet—who may only think he's been thinking too much—thinks that thinking is only one part wise to three parts cowardly.