Tradition and prescription, which fetter the savage with iron bonds, exist for Caliban only in the form of the faith held by his dam, which he puts aside in the calm decisive way of a modern thinker, as one who has nothing to fear from the penalties of heresy, and has even outlived the exultation of free thought:-- "His dam held that the Quiet made all things Which Setebos vexed only: 'holds not so; Who made them weak, made weakness He might vex." [Footnote 43: It is characteristic that M.Maeterlinck found no place for Caliban in his striking fantasia on the _Tempest, Joyzelle_.] Caliban's theology has, moreover, very real points of contact with Browning's own.

His god is that sheer Power which Browning from the first recognised; it is because Setebos feels heat and cold, and is therefore a weak creature with ungratified wants, that Caliban decides there must be behind him a divinity that "all it hath a mind to, doth." Caliban is one of Browning's most consummate realists; he has the remorselessly vivid perceptions of a Lippo Lippi and a Sludge.
Browning's wealth of recondite animal and plant lore is nowhere else so amazingly displayed; the very character of beast or bird will be hit off in a line,--as the pie with the long tongue "That pricks deep into oakwarts for a worm, And says a plain word when she finds her prize," or the lumpish sea-beast which he blinded and called Caliban (an admirable trait)-- "A bitter heart that bides its time and bites." And all this curious scrutiny is reflected in Caliban's god.

The sudden catastrophe at the close ("What, what?
A curtain o'er the world at once!") is one of Browning's most superb surprises, breaking in upon the leisured ease of theory with the suddenness of a horrible practical emergency, and compelling Caliban, in the act of repudiating his theology, to provide its most vivid illustration.
Shakespeare, with bitter irony, brought his half-taught savage into touch with the scum of modern civilisation, and made them conspire together against its benignity and wisdom.

The reader is apt to remember this conjunction when he passes from _Caliban_ to _Mr Sludge._ Stephano and Trinculo, almost alone among Shakespeare's rascals, are drawn without geniality, and Sludge is the only one of Browning's "casuists" whom he treats with open scorn.

That some of the effects were palpably fraudulent, and that, fraud apart, there remained a residuum of phenomena not easy to explain, were all irritating facts.