Art vs. Nature in The Tempest
The debate between Art and Nature in The Tempest is very much based on the Renaissance debate, on whether “civilized man” or the "natural man" was superior. The advocates of “civilized man” presenting the "natural man" as being savage, intemperate and brutal in contrast to the nobility, self-control and high-mindedness of the “civilized man”. The advocates of "natural man" presenting him as what Rousseau was later to term the "noble savage" and the civilized man as being corrupt, affected, merely more adept at cloaking his vices, which were at best more refined, but nevertheless hardly a reason for pretensions to moral high ground. Montaigne, in his famous apologia for the "natural man", observes that it may be arguably more barbaric to "mangle by tortures and torments a body full of lively sense [...] under pretence of pietie and religion" than "to roast and eat him after he is dead".
Shakespeare does not go to either extreme in The Tempest. The "natural man" (i.e. Caliban) is savage, intemperate and brutal, incapable of higher reasoning and lacking the innate intelligence for nurture to "stick" (as Prospero says in frustration) responding only to something that in effect could be considered, not inaccurately, as what would in modern terms be called a form of Pavlovian conditioning. While his portrayal is not totally unsympathetic (cf. the touching passage in Act III Scene II where he speaks of his "cr [ying] to dream again", it can also be argued that Prospero's alighting on the island, installing himself as ruler, and consequently -- albeit not unjustifiably -- depriving Caliban of his rights and liberty is per se somewhat questionable, depending on how one views colonization) he is nevertheless far from being admirable, far from being a "noble" savage in any way. Admittedly, he does serve to show the implications of Antonio's conscious choice of evil despite being born of a "good womb" and having every advantage of mind and upbringing. However, he does not only "indicate corruption and degeneracy in the civilized world"; that would suggest a certain one-sidedness to the argument. On the contrary, he also serves as a contrast with the radiant virtue (Miranda and Ferdinand) and enlightened benevolence (Prospero, albeit more towards the end) of untainted nobility.
It is in this context that the debate between Art and Nature takes place. Art, using the stricter definition, refers specifically to Prospero's magic, which he uses to control Nature; this Art, though not without some questionable aspects, (cf. "graves at my command / Have wak'd their sleepers", and his excessive threats to punish Ariel in Act I for nothing more than a polite request that he remember to release him), is chiefly used for benevolent purposes (i.e. for the restoration and perpetuation of the appropriate social order, for the edification of the others e.g. Alonso). Even the tempest at the...