If Macbeth is indecisive, Lady Macbeth is just the opposite a character with such a single vision and drive for advancement that she cannot help but bring about her own demise. And yet her very ruthlessness is another form of ambiguity, for in swearing to help Macbeth realize the Weird Sisters' prophecy, she must cast off her femininity. In a speech at the beginning of scene five, she calls on the spirits of the air to take away her womanhood:
Come you spirits
That tend on mortal thoughts, unsex me here,
And fill me from the crown to the toe top-full
Of direst cruelty. Make thick my blood.
Stop up th'access and passage to remorse,
That no compunctious visitings of nature
Shake my fell purpose, nor keep peace between
Th'effect and it. Come to my woman's breasts
And take my milk for gall, you murd'ring ministers (I.v 47-55).
Lady Macbeth sees "remorse" and "peace" as feminine virtues, and in order to void herself of such compassion she must be "unsexed." That she sees femininity as soft and kind is evident in the fact that she calls the waffling Macbeth womanish, telling him that only when he has murdered Duncan will he be a man. And whereas she wants to turn her mother's milk into "gall," she complains that Macbeth is "too full o' th' milk of human kindness" (I.v 17). Later she reinforces the rejection of her femininity by claiming that she would go so far as to cast off all of the motherly sentiments that go along with it:
I have given suck, and know
How tender Œtis to love the babe that milks me.
I would, while it was smiling in my face,
Have plucked my nipple from his boneless gums
And dashed its brains out, had I so sworn as you
Have done to this (I.vii 61-67).
However, this does not mean that in rejecting her femininity she becomes a man. Instead she becomes a woman devoid of the sexual characteristics and sentimentality that make her a woman. She becomes entirely unnatural and inhuman. Like the supernatural Weird Sisters with their beards, Lady Macbeth becomes something that does not fit into the natural world.
