Act 4 Scene 1

Prospero's anger is also the frustrated anger of the Renaissance humanist and educational theorist, once optimistic about the ability of nurture to improve upon and even transform nature

The theory fails - not, as Prospero sees it,because of any fault in his methodology, but because his pupils have been essentially good or bad by nature

Caliban urges them on, gaining an ascendency over them which is expressed first in his speech - verse and not prose - and then in his contempt for their greedy seizure of the 'trumpery'

Now Prospero is a truly terrifying figure: we know that he is able and willing to inflict great pain, and he has given ample demonstrations of his power to paralyse  and disarm any one who opposes him

• At this hour / Lies at my mercy all mine enemies