Vico famously (or notoriously) claimed that human truth was like a painting. He was also a neo-Platonist, at least to the extent that he believed that in our fallen world we can at best approximate to the ultimate metaphysical truth, which can be approached only through the exercise of poetic fantasy. In a fascinating monograph Inventing Falsehood, Making Truth: Vico and Neapolitan Painting (Princeton University Press, 2013), Malcolm Bull locates Vico's thought against the background of the seventeenth century Italian baroque.

In a general sense baroque painting works in a highly theatrical manner, drawing the viewer into compelling dramas played out before their eyes. And this aesthetic itself can be linked to the Jesuit practice of meditation, whereby the meditator imagines him or herself present in one of the gospel scenes, asking what he or she would have done or felt at the time. The typical baroque altarpiece or ceiling can be seen as a vivid aid to this ‘composition of place’, highly theatrical in effect, and often anticipating techniques used to powerful effect on both stage and screen. (And not coincidentally, it was during the baroque era that what is today recognisable as theatre, opera and ballet all have their origins.)

But, as Bull shows, this general characterisation of baroque painting glosses over an important and controversial divide between those who remained stuck in the baseness of the everyday and those who used imagination to reach out to the ideal. On the one hand, there were the Caravaggistes, whom, as Bull tells us, were accused of being atomists, materialists and sensualists, even Epicureans (in the technical, philosophical sense), sticking to what Vico referred to as autopsy, the evidence of their senses as the criterion of truth. On the other hand, there were those, of whom Guido Reni might be taken as an exemplar, who tended to use their artistic imagination to elevate, not to deny the empirical appearance, but to intimate through it higher, better worlds than those we are surrounded with (which is what Vico himself thought that myth and poetry could do, literal falsehood, but higher truth). To take examples of the two tendencies, contrast Reni's calmly delightful Rape of Europa with Caravaggio's horrific Judith Beheading Holofernes, sparing us nothing in gore and terror.

A classical myth about painting, which from time to time formed the subject of paintings, is that of Zeuxis painting the maidens of Croton. The legendary painter, commissioned to paint a picture of Helen of Troy, assembles twelve girls, and constructs his ideal Helen from the best features of each. So the baroque may be looked at as a struggle between the followers of Zeuxis and the followers of Caravaggio; at least that is what Vico and, after him, Bull implies, with Vico incorporating his aesthetic position into his philosophy of mythical, poetic truth.

The weight of aesthetic judgement probably goes against the Zeuxians, but this may be because the one undisputed genius of the Italian baroque is Caravaggio. His dark religious dramas have a power which is absent from the fantasies of the likes of Reni, Solimena and Giordano. But are we being entirely objective here, or are we seduced by Caravaggio's genius? On the one hand his theatrical masterpieces, such as the Supper at Emmaus and The Beheading of John the Baptist, for all their impression of realism, are actually highly unrealistic if considered as representations of what actually happened, as much a product of imagination as anything by Reni, but just a different sort of imagination. And if we widen the discussion a little, to include an artist such as Botticelli, is it entirely clear that a Vico-esque attitude to poetic myth inevitably loses out over the quasi-realism of the Caravaggistes?

Maybe, though, there is a perennial attraction to the dark over the ideal, one from which philosophers are no more immune that others. This might indeed be a somewhat unkind response to Dale Jamieson's Reason in a Dark Time: Why the Struggle Against Climate Change Failed – and What it Means for Our Future (Oxford University Press, 2014). In a way the rather long title says it all, and those expecting dispassionate philosophy or even dispassionate history should look elsewhere. In fairness to Jamieson, he tells us just that. ‘I am a philosopher by training but some of my colleagues will have a hard time recognising this as a philosophy book.’ (ix, in the Preface). The long account of various climate change meetings and resolutions which follows is, as he warns us on page 2, ‘opinionated’, with which American Republicans, Chinese industrialists, and people who simply drive cars for family reasons or fly for pleasure, would probably agree. Aside from the history, and a rather convoluted defence of the peer review system which supports climate change science, much of the book is devoted to arguing that traditional economics, traditional morality and even evolution itself cannot show us what to do in our present predicament. So we need new ways of thinking, but it cannot be said that these are presented as offering great hope: ‘we will have to abandon the Promethean dream of a certain, decisive solution and instead engage with the messy world of climate politics’, hoping (against hope?) that the ‘darkest scenarios do not come to pass’.

And what is our present predicament and the darkest scenario? ‘Over the next few centuries, climate change risks putting an end to a great deal of what we value, including much of humanity and its creations.’ (1) In this situation of risk, our Enlightenment dream has failed; human rationality no longer governs the world, but is at risk from monsters (governments, technologies, institutions, economic systems) it or we have created (hence the ‘opinionated’ history which occupies the first part of the book, trying to show us why rationality has failed).

Everyone can agree that there is a ‘risk’ of humanity coming to an end over the next few centuries, or even to-morrow. And maybe climate change caused by us (so-called anthropogenic climate change) is one of the things which might make that risk into something actual. But maybe, as Jameson himself says right at the start of the book, ‘climate change will not be worse than other things humanity has survived’ (ix). And maybe, a critic of Jamieson might urge, other things might be worse and happen sooner (e.g. a nuclear war in Pakistan or the Middle East, or an unstoppable, mutant ebola virus from West Africa infecting everyone). Maybe, assuming that we are not destroyed by wars or other scourges, defences can be erected against rises in sea levels caused by global warming (as they were in Holland in the middle ages, with only spades and shovels – see Faust, Part 2). Bangladesh indeed has developed some impressive defences against cyclones and the like which it did not have a few decades ago (as Jamieson admits). And maybe again, not everything about global warming/climate change is bad (e.g. if it contributes to higher agricultural yields in places that are currently barren). Everything in these areas depends on calculations of risks and probabilities, which, in the nature of the case, are fraught with uncertainty, including of course the uncertainty that some new fuel technology might not be developed which does not rely on emitting CO₂.

The argument is going to hang on our evaluation of the likelihood of our current practices continuing in such a way as to bring about unstoppable devastation of our world. It has to be said that the evidence adduced by Jameson in this regard might not seem compelling to someone not already persuaded in his direction. CO₂ emissions have increased from 280 parts per million in 1750, to around 400 ppm now, and are continuing to increase by around 2 ppm per year. The atmospheric concentration of CO₂ is ‘now almost 10% greater than it was in 1992 (and) we have already experienced a warming of 0.8 degrees C, and there is no end in sight.’ (59–60). Yes, but this temperature increase is not since 1992; it is over the last century or more. Jamieson could have pointed out that of this global warming of about 0.8 degrees C over the last 150 years, 0.5 degrees occurred between 1975 and 2000, but then he would have had to add that over the last 15 years, according to the latest Intergovernmental Panel of Climate Change report itself (in 2014), and despite greater carbon emissions, global warming has been at a rate of 0.05 degrees C per decade, plus or minus 0.1 degree C. What are we to make of this apparent slowing-down of warming despite increased carbon emissions?

What seems to emerge from all this is that global warming may not be as great or as fast as it once seemed, and there is also considerable and reasonable uncertainty about the contribution CO₂ emissions make to it. Notoriously this is an area in which, peer review notwithstanding, some scepticism over what we are told is the scientific consensus may be in order. Only recently a paper, whose co-authors included the distinguished meteorologist Lennart Bengtssom, which argued that a doubling of CO₂ emissions would lead to a temperature increase of between 1.2–2.7 degrees C, was turned down by Environmental Research Letters, one of the referees saying that its publication would be ‘less than helpful…’ The Bengtssom estimate was unhelpful, presumably, because it is out of line with the IPCC's estimate of an increase of 1.5–4.5 degrees C, and the dissenting paper's recommendation of further work on what is now called climate sensitivity. Moreover even the IPCC's own estimate of temperature rises has a margin of difference of 300%, which is hardly a precise or severely testable prediction; and as Jamieson himself remarks, there is a considerable difference between a warming of 2.5 degrees, and one of 5 degrees. So when can we expect a temperature increase of 2 degrees (which seems to have been generally accepted as what we have to act to avoid)? Would such an increase actually be indefensible, particularly if it came about gradually over a long period? And, crucially, even assuming we continue to rely on fossil fuels in the way we do now, would a massive reduction in their use now (were the non-industrialised nations ever to agree to such a thing) do more harm now than a small degree of warming sometime in an unpredictable future?

Jamieson considers the claim that anthropogenic climate change violates human rights, presumably those of people yet unborn. He has some interesting points to make here (partly as part of his attempt to show the inapplicability of our current ethical thinking to the problem); but, useful as what he has to say here might be, what he might more profitably have turned his attention to is the question as to whether depriving poor people living in the world now of fossil fuels now would violate their rights now. The notion that we have to deprive people now of the possibility of a decent living in order to secure some better future of which we can know very little is one we are familiar with from contexts other than climate change. Jamieson's book raises important questions, but his rather vague invocation at the end of the need for ‘respect for nature’ might suggest that his own position rests more on faith than reason. (What does ‘respect for nature’ mean in practice? Does nature know best? We are not told.) Jamieson insists that ‘large sums (of money) have been spent to further confuse and misinform us’ on climate change (104). This may be true, but a more reasoned approach to the issue, maybe bringing some light to our dark time, would have been to have faced up philosophically to the doubts and difficulties inherent in all the discussions of climate change.