In Macbeth, Shakespeare chooses the chronicle story of 11th century Scotland to fashion out a complex Renaissance tragedy of ambition. The play has also been called Shakespeare's most profound vision of evil.
The three witches underscore, in the very opening scene, the state of moral confusion in Duncan's Scotland:'Fair is foul and foul is fair', the syntactic inversion of their formula suggesting a deeper inversion in the moral world of man. The witches are going to meet Macbeth on a heath, the meeting taking place in act1 sc.3.
King Duncan's 'valiant kinsman' Macbeth is noble and heroic as he proves himself 'Bellona's bridegroom' in the field of battle, fighting gloriously against the rebel Macdonwald, the invading Norwegian king, and the treacherous thane of Cawdor to register victory for Duncan. This victorious general, Macbeth, is 'fair' as he is loyal to his king, courageous, and acting in full trust. Duncan instantly promotes Macbeth to the position of the thane of Cawdor.
But the same Macbeth is secretly ambitious to occupy the throne of Scotland. As the witches hail him as Glamis, Cawdor, and the future king of Scotland, Macbeth starts, 'seems rapt withal', charges the weird sisters to know more about their prophecies. As Ross informs Macbeth that the king has announced to confer the title of Cawdor on him, Banquo is surprised to comment:'What! can the devil speak true?'. The witches are agents of evil, voicing the perilous design of the forces of darkness; but how can they speak favourably to portend Macbeth's prosperity? Macbeth's asides to follow show how 'fair' Macbeth is already given to 'foul' ambition and its attending foulness to translate his ambition to reality:
" Glamis, and Thane of Cawdor:
The greatest is behind".
and
" Two truths are told
As happy prologues to the swelling act
Of the imperial theme....................
This supernatural soliciting
Cannot be ill; cannot be good: if il,
Why hath it given me earnest of success,
Commencing in a truth?.......................
If good, why do I yield to that suggestion
Whose horrid image doth unfix my hair
And make my seated heart knock at my ribs,
Against the use of nature?"
Macbeth is surely already tempted deep within himself by his own evil ambition, and the thought of killing Duncan is there hidden in his mind. These lines hold the proof of the deep-seated evil in Macbeth:
" Present fears
Are less than horrible imaginings:
My thought, whose murder yet is but fantastical,
Shakes so my my single state of man that function
Is smother'd in surmise, and nothing is
But what is not".
The conflict between ambition and conscience, between 'fair' and 'foul' in the protagonist's self-divided personality is the crux of Shakespeare's tragedy. The soliloquies of Macbeth bear ample testimony to this moral-psychological conflict: a fair and greatly admired personality falling a victim to the hovering evil operative through illegitimate ambition. Let us consider the following samples:
a) "...........................I have no spur
To prick the sides of my intent, but only
Vaulting ambition, which o'erleaps itself
And falls on the other".
b) " What hands are here? ha! they pluck out mine eyes!
Will all great Neptune's ocean wash this blood
Clean from my hand? No; this my hand will rather
The multitudinous seas incarnadine,
Making the green one red".
c) "Come seeling night,
Scarf up the tender eye of pitiful day..".