Is Macbeth responsible for his own actions, or do the witches control him?William Shakespeare's Macbeth

In response to this question, the reader must keep in mind
that Elizabethans felt that the supernatural world was in direct competition with the
natural world. Ghosts, especially, were thought to have a profound effect upon the
natural order of events.  Taking advantage of these Elizabethan beliefs, Shakespeare
employed elements of the supernatural world in order to create dramatic emphasis rather
than direct affect upon the actions of characters.

That
Macbeth wishes to make use of the supernatural as cause for his actions is apparent in
the first act:

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If chance will have me King, why, chance may
crown me,

Without my stir.
(1.3.155-156)

But, he does
not deceive himself long about the influence of the supernatural being all that effects
events.  For, in his ambivalence regarding murdering Duncan, he admits to his tragic
flaw:

...I
have no spur

To prick the sides of my intent, but
only

Vaulting ambition, which o'erleaps
itself

And falls on
th'other--(1.7.25-28)

In
subsequent acts, also, Macbeth does not deceive himself.  In Act II, for instance, he
tells Lady Macbeth,

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I'll go no more

I am
afraid to think what I have done.
(2.2.50-51)

And, in this same
scene, Macbeth regrets his actions without any blame attributed to
fate:

Had I
but died an hour before this chance,

I had lived a blessed
time; for from this instant

There's nothing serious in
mortality. (2.3.99-101)

As
his paranoia increases, Macbeth does consult the witches, but his actions in response to
their predictions are more in defiance of the supernatural rather than in accord with
it, thus providing the dramatic effect mentioned earlier.  In Act V, Macbeth
acknowledges the evil he has committed:

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...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)

Thus, in his
"vaulting ambition which o'er leaps itself," Macbeth chooses to allow the predictions of
the three witches to motive his own actions to be king.