Eating without pleasure, crying without pain
Nature, in the sense sketched in the Introduction, encompasses a great deal, from London's Hyde Park to the Okavango delta in Botswana. So, in thinking about it, where is one to start? One option would be to begin with those of its parts that seem to be most like us – namely, nonhuman animals (hereafter ‘animals’). But that topic is still unmanageably large. For with which animals should one begin? Talk of animals in general can suggest, implausibly, that there are no significant differences between different kinds of animal – between, say, a Sumatran rhino and a spiny-headed worm. It can, moreover, obscure the fact that there are sometimes huge differences between animals belonging to the same phyla (for instance, octopuses are much smarter than oysters, though both are molluscs). Even references to the characteristics of a particular species conceal the variation that exists amongst the individual members of that species.
Nonetheless, philosophers through the ages have made a number of sweeping claims about animals, for which they are only partly excused by their ignorance of modern biology. And, as we shall see, many of these claims are directly relevant to environmental philosophy.
Let's begin with one of the most notorious of these claims, courtesy of the early modern French thinker Nicholas Malebranche (1638–1715):
For Malebranche, then, there is nothing it is like to be a dog, say, or a horse, just as there is nothing it is like to be a table or a teapot. No such entities are conscious; they are all mindless mechanisms. The suggestion seems far-fetched, to say the least. We naturally assume that when a dog, for instance, drops to its forepaws, it is doing so because it wants to play; that when it whines, it does so because it is feeling hungry; that when it sits and gazes longingly at the front door, it is hoping for its owner's return. But although this is how things seem in such cases, is there really no room for doubt? Might it not be, as Malebranche would insist, that the dog is merely acting as if it were conscious? After all, one cannot look inside the animal's head to check. One can only appeal to its behaviour. And the behaviour of a conscious dog cannot be distinguished from the behaviour of a dog that is merely behaving as if it were conscious. Indeed, can't these sceptical worries be taken further? Is it not possible that not just dogs but all animals are mindless mechanisms? Is it not possible that Malebranche was right?
The first thing to note about this line of reasoning is that it presupposes a certain conception of what interpersonal understanding involves. It rests on the assumption that, although one can directly apprehend one's own mental states by means of introspection (as when Shirley knows that she is feeling pain), those of others cannot be directly apprehended, but must instead be inferred on the basis of how they behave (as when Shirley infers that Pierce is in pain because he is swearing loudly and clutching his foot). Although there is not enough space here to explain their arguments, it is worth noting that several writers in the fields of phenomenology and philosophy of mind have challenged that general conception of interpersonal understanding (see, e.g., Ratcliffe
2007: ch. 5; Zahavi
2010). But suppose, for argument's sake, that those writers are wrong and that it really is impossible to directly apprehend the mental states of others. Making that assumption not only casts doubt on any claims about the mental
lives of dogs; it calls into question claims about the mental lives of any
other beings, whether human or nonhuman. So, adopting this sceptical standpoint, I might conclude that I am unable to get inside Fido's head to determine whether or not there is anything going on there. However, continuing these sceptical thoughts, I might arrive at the conclusion that I am unable to get inside my brother's head to determine whether or not there is anything going on there
. Granted, Adrian can tell
me that he is thinking and feeling certain things. But can I be certain that he is not merely a complicated mechanism, bereft of consciousness but capable of simulating speech? In fact, can I be absolutely certain that I am not the only conscious being in the universe?
This, however, is not the place to assess whether that last, crazy claim – a statement of solipsism – is true. (And, anyway, if it is true, I have bigger worries.) For now, it will be enough to consider Malebranche's claim: that no nonhuman animals are conscious.
What are the chances of that claim being true? Well, unlike the claim that square circles or married bachelors exist, it is not absurd, which is to say that its truth is not a logical impossibility. That said, a great many extremely implausible states of affairs are logically possible, so that is not much of a concession. It is a logical possibility, after all, that everyone named Algernon is a shape-shifting wizard. It is also logically possible that we are living in a virtual reality simulation run by a technologically advanced race of alien reptiles.
Yet, leaving the matter of merely logical possibilities aside and returning to the real world, is there any evidence
for thinking that any nonhuman animals are conscious? To many people, and in particular to those who live and work with social mammals such as dogs and horses, the claim that no animals are conscious will seem extremely implausible. It certainly seems so to me. The proposition that dogs are mindless mechanisms strikes me as being so fanciful that I have a hard time imagining what the world would be like if it were true. It is, I believe, misleading to say that I am nearly 100 per cent certain that dogs are conscious. As I write, I am nearly 100 per cent certain that Rabat is the capital city of Morocco, but should that belief turn out to be false, I will simply make a note of the new item of knowledge and my life will carry on pretty much unchanged.2
But what if dogs turned out to be mindless mechanisms? That new item of knowledge would rock my world to its foundations. For one thing, I would have to reappraise all those moments I have spent in the company of dogs, walking, running
and playing with them. In fact, if they really were mindless mechanisms, would it be correct to say that I was in their company
So although I cannot seriously doubt that dogs are conscious, this is not because I believe there to be overwhelming evidence in favour of the hypothesis that they are conscious. A commitment to the consciousness of dogs is installed at a more basic level in my form of life than talk of evidence and hypotheses would suggest (cf. Gaita
2003: 39–52; Dupré
2002: 217). Yet that personal observation only proves so much. Maybe some reasonable people can
seriously doubt that dogs are conscious. And, even if that is not possible, matters quickly become much murkier when we move beyond the category of dogs and other mammalian companion animals. What of kingfishers, cobras, salamanders, octopuses, lobsters, sharks, beetles, scorpions and centipedes? To assess whether any such creatures are conscious, we will need to consider scientific evidence. And to investigate our moral relations with them (as we shall do in later sections), we will need to assess the evidence that some of them are sentient
– that is, capable of feeling pain or suffering.
First, there is behavioural evidence. Many animals respond to bodily damage in ways that are not unlike the ways that human beings respond. Upon treading on a drawing pin, a dog will yelp and quickly withdraw its paw, and afterwards it will avoid putting its weight on the damaged limb. It is true that not all animals respond in such ways (insects, for instance, do not avoid using damaged limbs). And it is also true that one could dig in one's heels and continue to insist that yelping dogs are merely behaving as if they are in pain. However, behavioural observations of this sort surely lend some support to the hypothesis that some animals can feel pain.
Second, there are various items of physiological evidence. A great deal of attention has been paid, in this context, to the presence of endogenous opioids, substances which, in humans, are released in order to alleviate the pain resulting from major injury. Interestingly, such opioids have also been detected in a wide range of nonhuman animals – even insects and earthworms (Varner
1998: 53). Or consider nociceptors. In human bodies, nociceptors respond to damaging or potentially damaging stimuli by sending nerve signals to the spinal cord and the brain, leading to the feeling of pain. Yet nociceptors are also present in many nonhuman animals, including all birds and mammals. For sure, in order to be conscious
of pain, a being would seem to require a central nervous system; however, fish,
reptiles, amphibians, birds and mammals all meet this criterion as well.
Identifying and comparing these various items of behavioural and physiological evidence is no easy task, especially since many animals meet only some of the relevant criteria. For instance, although insects possess endogenous opioids, they lack central nervous systems and their behavioural responses to pain are quite unlike those of, say, mammals. Fish, reptiles and amphibians do not appear to possess nociceptors, yet their bodies have been found to contain endogenous opioids, they do have central nervous systems, and (like mammals, for example, and birds) they tend to avoid damaging or potentially damaging stimuli. Matters are further complicated by the possibility that different physical structures might be able to perform similar mental functions – that, for instance, a certain kind of feeling could be identified with either a certain state of a mammalian body or a very different state of an avian or reptilian body. Nonetheless, taken as a whole, the evidence suggests that, although all vertebrates can feel pain, most invertebrates cannot.3
Such, at least, was the conclusion of the multi-disciplinary working group that was convened by the UK's Institute of Medical Ethics to investigate the use of animals in biomedical research (Varner 1998: 52).
So there is compelling evidence that many animals are capable of feeling pain. There is, moreover, evidence that many of them are also capable of experiencing aversive states such as fear, anxiety and boredom. For example, behavioural studies have shown that many animals can exhibit the characteristic symptoms of fear, such as frequent urination and raised heart rate. In fact, many anti-anxiety drugs that are prescribed to humans have substantially similar effects on nonhuman mammals (Rowlands
2002: 10). Besides, as with the ability to feel pain, it is easy to see how a capacity to experience some degree of fear in the appropriate circumstances could have evolved through natural selection. If you're a rabbit or an antelope, it probably pays to be a bit nervy.