Roberto Calasso, the erudite Italian investigator of the black arts, has lightened up: he has written a celebration of the colour pink, the blood-flushed tone exemplified by Tiepolo's nymphs who flaunt and frolic in divine harems on walls in Venice and ceilings in the Residenz at Würzburg and the Royal Palace in Madrid. Starting with The Marriage of Cadmus and Harmony (1993), Calasso's earlier books delved into the murky residue of pagan myth and tracked the obscure underground river of pseudo-science – magic, alchemy, cabbalism, the occult – that contradicts our pretence of living in a scientific culture. Now he has reached the Enlightenment, and he defies its rationalism in a book that treats painting as a kind of sorcery.
Calasso is himself a myth-maker, and he begins by resetting the date at which the fall of man occurred. "Tiepolo: the last breath of happiness in Europe," he declares. The 18th century was a paradise of frivolity, which solemnly recognised the pursuit of happiness as the legitimate aim of human life. Tiepolo (1696-1770) illustrated that idyll in paintings that are frothily theatrical and warmly carnal. Even his angels have nubile bodies and secondary sexual characteristics. On a painted ceiling in Venice that is meant to be "strictly devotional", Calasso notices that one of these seraphic beings raises his arm to disclose a "soft down" of armpit hair, "not customary with angels". The clouds on which Tiepolo's goddesses float, as Calasso nicely puts it, have the springy consistency of "congealed foam", like vast beds. Heaven is nothing more than a sublimation of earthly pleasures. All are welcome to the revels: in a weird multicultural reverie, Calasso suggests that Tiepolo's ceilings represent "the sky of Europe – the only sky capable of embracing, with equal benevolence, all images, of gods and men, saints and nymphs, Olympus and Bethlehem". I'm not so sure: you were more likely to be invited to join in this aerial carnival if your skin was pink.
Europe's fall into misery took place, according to Calasso's reckoning, in 1789. Those with more sober minds and anxious political consciences think of the French Revolution as the inception of modernity. But for Calasso it was a disaster. "An epoch incapable of understanding, or even conceiving the tragic" – which is how he thinks of the 18th century – came to an abrupt end, and a new, nasty world emerged from the bloody rampages of political fanatics. This of course is not history but fantasy, and Calasso's book is a dreamy tour of the ancien regime. He has no interest in the revolutionary rights of man. "Every kind of humanism," he yawns, "is unsuited to grasp the divine, precisely because of its bias in favour of the human." Well, pardon me for not being an angel.
Calasso's abiding interest in hermetic lore, the subject of earlier books such as Literature and the Gods, returns here in his commentary on the enigmatic etchings Tiepolo called Capricci and Scherzi. These scenes of sacrifice and unorthodox worship, over-run by snakes that represent forbidden knowledge, cling to an "ancient alliance between invisible powers and visible talismans, between demons of the air and creatures of the flesh". Tiepolo's visual art is a sketch of a world we cannot see, an oracular glimpse of an atmosphere that teems with beings whose "spiritual power" can't be apprehended by our imperceptive eyes. It's a frustrating conclusion: the etched pages and painted canvases described by Calasso fade to white (or perhaps to a blushing pink).
Elsewhere there are riffs about the relationship between eating and looking, or the link between poison and imagery – bright ideas with no visible means of support. Even readers who want to be persuaded by Calasso may be baffled by the airy nonchalance with which he refers to "the Vedic adhvaryu and hotr", "the primordial Foh of Chinese origins", and the splendour that "the most ancient Greeks called dóxa". Is he a polymath or just a polyglot name-dropper?
Calasso confidently generalises about Europe yet admits that for him the continent is "an extension of Venice". Though he praises the "ecumenical humanity" in Tiepolo's paintings, his own sympathies remain partisan, even xenophobic. He can't forgive the French for the revolution or for their "feeling of sovereignty"; he pities Tiepolo for having to deal with Spanish patrons who cared only for "honour and dignity", not "the modality of appearance"; and he rebukes Michael Levey for dismissing the Scherzi as amiable oddities "in a typically English manner".
Such asides point up the peculiarly national bent of Calasso's sensibility. His absorption in pre-Christian mysteries is a symptom of Italy's unashamed paganism. This is the country of "la bella figura", where the way things look matters more than what's beneath the surface, and it's predictable but still faintly shocking to find Calasso seconding Italo Svevo's opinion that beautiful women always seem brainy because "a fine line or colour are in fact the expression of the most absolute intelligence". So is this why Berlusconi has rounded up a bubble-brained sorority of supermodels and showgirls as candidates in the next election? Perhaps Calasso might consider writing an essay on the prime minister's reafforested scalp and his impervious, unseasonal tan: Tiepolo Pink could be followed by Berlusconi Bronze.