A dagger of the mind

Is this a dagger which i see before me,
The handle toward my hand? come, let me clutch thee:--
I have thee not, and yet i see thee still.
Art thou not, fatal vision, sensible
To feeling as to sight? or art thou but
A dagger of the mind, a false creation,
Proceeding from the heat-oppressed brain?
I see thee yet, in form as palpable
As this which now i draw.
Thou marshall'st me the way that i was going
And such an instrument i was to use.
Mine eyes are made the fools o' the other senses,
Or else worth all the rest: i see thee still
And on thy blade and dudgeon gouts of blood,
Which was not so before.--there's no such thing:
It is the bloody business which informs
Thus to mine eyes.--now o'er the one half-world
Nature seems dead, and wicked dreams abuse
The curtain'd sleep now witchcraft celebrates
Pale hecate's offerings

[a bell rings.]

I go, and it is done the bell invites me.
Hear it not, duncan, for it is a knell
That summons thee to heaven or to hell.