of this version of Cartesian dualism developed by Val Plumwood in her two books Feminism and the Mastery of Nature and Environmental Culture: The Ecological Crisis of Reason: such dualism is there whenever humans put it in their heads that they live in a region levitating somewhere above the biosphere, independent of it, free and able to bracket it off as an inferior order unrelated to theirs, except as a storehouse of resources they can use up in perpetuity.16 Not so much a philosophical programme declared by avid preachers, more a syndrome than a credo, this dualism is present in everything from neoclassical economics to climate change denial and sheer indifference to issues of ecology. Devised for negligence, it has its own causal interaction problem: it has no idea about how society can cause a crisis in nature or vice versa.
To realise that there is an ecological crisis with great potential to affect humans is to break with substance dualism. We are, it turns out, of exactly the same substance as nature, inhabit the same planet and constantly touch each other all over the place. In terms of the philosophy of mind, this is a commitment to substance monism. From here, however, there are two paths to choose between. One can go on to argue that the social and the natural not only share substance, but that they have no significant properties that tell them apart – a substance monism and property monism. This is the position of the hybridists, of Bruno Latour and, as it happens, of Val Plumwood: there is only one substance, and everything made of it has the same essential attributes (we shall soon see what these are). Then there is the view that society is made up of the same substance as nature, but has some highly distinctive properties – what in the philosophy of mind is known as substance monist property dualism.17 To tease out this position, we may first turn to Dale Jacquette’s The Philosophy of Mind: The Metaphysics of Consciousness, a masterpiece in defence of it.
The quandary of mind and body that Descartes struggled with to such unsatisfactory effect has not gone away. My brain is a physical entity. It contains cells, tissue, fluid, neurons, synapses, blood vessels, matter white and black and grey. But do these things also make up my mind? ‘My mind’, Jacquette writes, ‘on casual inspection contains memories, desires, expectations, immediate sensations, embarrassments, likes and dislikes. But my brain on casual inspection contains none of these things.’18 Brain events have weight and colour, but thoughts seem not to. What colour is my thought that Donald Trump is a racist? How much does it weigh? Does it swerve if I turn my car sharply to the right? How could the physicality of that thought as thought be pinpointed and measured? Suppose I attend a concert with Run the Jewels, and suppose the intensity of the performance is heightened by a jury having just acquitted a white policeman for shooting and killing a black man, and suppose a neuroscientist at this moment drops in to subject my brain to observation. She will see neurons firing and flaring like firecrackers, but she cannot possibly inspect or capture my conscious experience as such, the quality of taking in the musical furore or the feeling of shared fury. These subjective states appear nothing at all like the features of a material object. As such, they are not available for third-person observation in the way a microphone or a T-shirt is, nor can they be read off from neuroscientific instruments or described in a strictly physical language.19
At a first introspective glance, one may indeed be tempted to infer that the mind is something quite disparate from the body. But, then again, we have no hard evidence of disembodied thoughts, no knowledge of minds unattached to brains, no data to suggest that some sort of souls live on after their bodily beds have perished. We have, on the other hand, a surfeit of experiences of the mind directing the body to perform various deeds and of the body interfering with the workings of the mind; as for the latter causal route, anyone who has been under the influence of alcohol or psycho-active drugs can testify to its existence, and the assault on the senses during a concert must surely be the ignition of the mental fireworks. The relation appears to be one of dependence and difference. How can the two be reconciled?
The solution of substance monist property dualism – or just ‘property dualism’, more conveniently – begins with the recognition that the brain is the seat of all mental occurrences. The latter must come to an absolute, impassable end when the former ceases to be. But this suggests that the physical entity of the brain, and the human body as a whole, is a bearer of mental properties, which cannot themselves be reduced to sheer materiality or equated with physical components. They are lodged in the body and inextricable from it: hence they belong to the exact same substance. They are non-physical properties of the body, the sum of which makes up the mind.20 Its signal marker is what Jacquette and other philosophers call ‘intentionality’. A thought is always about something. It points to an intended object, be it the daughter I long for, the food I crave, the argument I develop, the God I doubt, the storm I expect, the stomach pain that troubles me or the fascistisation of society that frightens me. In this context, ‘intentionality’ refers to an abstract relation between a mental state and an object, a link by which the former is directed towards the latter. It is an aspect of the thought itself – it is not this or that capillary or cortex that is about something; considered as a purely material entity, the brain is not turned towards a daughter or a dinner. It gives rise to the mental property of intentional thought, which is distinct from any physical property of the brain and inexpressible in the language pertinent to that underlying level. No one has yet explained how one could possibly scan the brain and pick out the neurochemical state that is about Donald Trump and not about Daenerys Targaryen.21
Moreover, when I think about Daenerys Targaryen and ponder her next move in the campaign for seizing Westeros, my thought is about a person who does not exist. Since she is a fictional figure, she cannot be physically connected to the material objects that make up my brain. Here it will not do to say that I am really thinking about the book by George R. R. Martin or the HBO series, since my thought concerns none of these things, but precisely Targaryen herself and her next tactical manoeuvre. I can think of many other things that do not exist in the here and now, inter alia a world that is six degrees warmer. This ability to engage with things that do not (yet) exist – something the brain and nervous system could never do, considered strictly as such – establishes a peculiar orientation towards the future, an openness to various options, the art of formulating a goal, faculties such as imagination and creativity and cunning. It follows that ‘the mind is a new category of entity in the material world.’22 Property dualists like Jacquette are adamant that there is nothing miraculous about this appearance – after all, science teaches us that life, with its amazing properties, evolved spontaneously once matter had organised itself into sufficiently complex patterns.23 So why should not life at a certain stage of its evolution be able to develop the wonder of the mind? Intentionality is an emergent property that cannot be reduced to the bedrock on which it supervenes, and cannot exist without it. All thought is actualised by events in the brain, and all thought has at least one property the matter of the brain cannot have sensu strictu.24
Property dualism, then, admits of only one substance – matter – but considers the human body a species of that substance in possession of uniquely mental properties. The beauty of this solution is that it avoids the Cartesian impotence in the face of the causal interaction problem while preserving the distinction between body and mind. As much as substance dualism fails on the former count, substance and property monism – or double monism – fails on the latter. Jacquette clinches his case with a particularly powerful example:
What if a history of the Watergate scandal were to be given in a book filled with nothing but chemical formulas describing the brain and other physical events that took place at the time involving participants in the break-in, wire-tapping and cover-up? … Would such a chemical history explain these social-political episodes, even to the neurophysiologist well-versed in understanding chemical symbolism? If anything, it appears that property monist explanations suffer from an explanatory disadvantage in comparison with property dualist accounts of social and psychological phenomena.25
And here we are right back at the relation between society and nature.
While Cartesians spread their intellectual
