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Descartes versus Cudworth On The Moral Worth of Animals

Samuel Kaldas compares two views on the nature of animals and their implications for our moral responsibility towards them.

“No one understands animals who does not see that every one of them, even amongst the fishes, it may be with a dimness and vagueness infinitely remote, yet shadows the human…”
– George MacDonald, The Princess and the Goblin (1872)

Back in March 2008 the collective rage of the internet was roused against a U.S. Marine who was filmed throwing a puppy over a cliff. The grainy footage posted on YouTube showed the soldier holding the small black and white puppy by the scruff of the neck and remarking how cute it is before violently flinging it over the edge. Naturally enough, the public was outraged, and the Marine in question was discharged.

Perhaps there were circumstances surrounding the incident which, if we knew them, would make the whole thing seem (slightly) less monstrous: the Marine apparently claimed that the puppy was terminally ill. Even so, the fact that the video outraged so many people proves that for most of us, animals have a moral significance; it matters how we treat them. If the Marine had been filmed throwing a fancy watch over the cliff, none of the moral outrage would have followed. Implicitly then, we believe that there are important moral differences between animals and inanimate objects. Thus, even though our society is guilty of enormous industrial cruelties to animals, we tend to believe that we ought to treat animals well, because, unlike inanimate objects, they are living, feeling creatures.

Descartes’ View of Animals

Descartes with puppy
René Descartes and ‘friend’

This moral difference between a puppy and a laptop might seem obvious to us, but it was not at all obvious to the father of modern Western philosophy, René Descartes (1596-1650). Descartes famously thought that animals were merely ‘mechanisms’ or ‘automata’ – basically, complex physical machines without experiences – and that as a result, they were the same type of thing as less complex machines like cuckoo clocks or watches. He believed this because he thought that thoughts and minds are properties of an immaterial soul; thus, humans have subjective experience only because they have immaterial souls inhering in their physical bodies. However animals, reasoned Descartes, show no signs of being inhabited by rational souls: they don’t speak or philosophise, and so (as far as we can tell) they lack souls, and minds. So ultimately, Descartes thought that animals were not hugely different from cars or computers; they were mechanical objects and not living subjects. See his Discourse on Method (1637) and Meditations (1641) for his elaboration of this idea.

Of course, Descartes has been repeatedly and mercilessly criticised for this view, especially in our time, when far fewer people share it. In Descartes’ defence, modern scholars such as John Cottingham have shown that Descartes couldn’t quite stomach his own strict separation of man and beast (‘A Brute to the Brutes’: Descartes’ Treatment of Animals’, Philosophy 53, 1978). Thus, Descartes speaks of animals having sensations, and even feeling emotions like anger and happiness, even though a strict adherence to his dualism would demand that they could only do so if they possessed an immaterial soul. Prevarications like this suggest that, in practice at least, Descartes saw a meaningful difference between animal life and inanimate objects. And it would be hugely unfair to ignore the fact that Descartes had a pet dog, Monsieur Grat, whom he probably loved dearly. But such evidence can only exonerate the man so much. Pets and prevarications aside, Descartes undeniably did set up a strict dichotomy between the immaterial, experiencing, thinking life of man, and the material, mechanical, mindless existence of animals. That dichotomy certainly doesn’t encourage any sense of kinship between man and beast. Rather, it seems to imply that killing a puppy is no worse than spilling coffee on a computer (to take a modern analogy).

Descartes seemed aware that his view absolved us of moral responsibility towards animals. In a letter to the Cambridge philosopher Henry More, Descartes argued: “[My] view is not so much cruel to beasts but respectful to human beings… whom it absolves from any suspicion of crime whenever they kill or eat animals” (reprinted in Penguin Classics’ edition of Mediations and Other Metaphysical Writings, trans. Desmond M. Clarke, 1998). So although this view doesn’t make throwing a puppy over a cliff a good or a wise thing to do, it doesn’t suggest that doing so is particularly wrong.

Cudworth’s View of Animals

A modern reader of Descartes who wanted to refute this view would probably begin by attacking his idea of the soul as the source of subjective experience. Today, we tend to believe that subjective experience arises from the brain rather than from some mysterious non-physical entity. If subjectivity is generated by the brain, then the structural similarities between human and animal brains strongly suggest that animals (and especially mammals such as puppies) have subjective experiences. If animals’ brains give them subjective experiences like ours, then we cannot kill, eat or harm them with total insouciance, as we might scrap an old lamp or a set of headphones that definitely lack that subjectivity.

The response to Descartes I want to look at here though, is not modern. It belongs to a now little-known philosopher called Ralph Cudworth (1617-1688), a younger contemporary of Descartes. Cudworth was an Anglican theologian, a keen Classicist, and for most of his career, Cambridge University’s Professor of Hebrew. Along with the aforementioned Henry More, he was a leading member of a group of philosophers known as the Cambridge Platonists, who promoted the relevance of Platonic philosophy to contemporary life and thought. Although he agreed with Descartes on many things, Cudworth thought (as did More) that Descartes’ view of animals as mindless machines was implausible. For Cudworth, it was clear that an animal is much more like a living, feeling human than an inanimate machine. But Cudworth didn’t think that the similarity between man and beast was purely biologically based, as most of us would argue today. Instead, Cudworth argued that animals, like humans, have souls.

According to Cudworth, Descartes’ mistake was that his conception of the soul was too narrow. Descartes thought that animals’ inability to speak or think reflectively like humans was explained by their not having souls and thus being purely physical machines, but Cudworth saw a problem with this: animals might not speak or reason, but they still do an awful lot. As Cudworth saw it, anyone who can look at the incredible variety and complexity of animal behaviour and decide that it is all merely physical mechanism “will never be able clearly to defend the incorporeity and immortality of human souls” (The True Intellectual System of the Universe, 1678, p.44). In other words, if animals feel and move and communicate as they do purely because of their physical makeup, then there’s no reason to introduce a special, immaterial soul to explain human behaviour. If Descartes is willing to explain the behaviour of all animals as resulting from nothing but ‘blood and brains’, why shouldn’t he draw the same conclusion about us?

For a seventeenth-century Platonist, that’s a surprisingly modern insight; in fact, it’s not unlike the sort of argument many materialists would use to refute Descartes’ dualism today. But Cudworth was not a modern man, and like Descartes, he accepted the orthodox assumption of his time that conscious minds are souls. As we have seen, he was also committed to bridging Descartes’ radical gap between human and animal life. And so, instead of showing that neither animals nor humans have souls, he tried to show that animals have souls too. And although Cudworth thought that animal souls were less perfect and less conscious than human souls, he believed that nevertheless, their existence gives us moral responsibilities towards animals that we do not have towards soulless, mindless objects. So for Cudworth, the specialness of human souls does not entail the worthlessness of animal ones: rather, animals are simply less complex, less developed examples of the same sort of thing that humans are.

Cudworth contra Descartes

Given that today people tend to reject the idea of immaterial souls as outdated, it is tempting to dismiss Cudworth’s talk of ‘animal souls’ completely. If we don’t even believe in human souls, why should we bother with a theory that attributes them to animals too?

Well, for one thing, even if we reject their metaphysical underpinnings, Cudworth’s ideas make for an interesting counterpoint to Descartes’ view; one with important moral consequences. And besides that, I think we will find Cudworth’s concept of the soul much less bizarre once we get to know it better. It is radically different to Descartes’ conception, and you might even say that it has a modern feel. The soul, for Cudworth, is not so much a ‘disembodied mind’ as a kind of life-force that vivifies and animates all life.

However, to understand Cudworth’s concept of the soul as a life-force, we need to first briefly consider Descartes’ dualism, to which it is a response.

Descartes divided all reality into two kinds of things: thinking things (res cogitans) and extended things (res extensa). Thinking things, such as God, angels and human souls, are immaterial and independent of the physical world. Extended things, such as human bodies, animals, plants and inanimate matter, are extended across the three dimensions of physical space. Subjective experience belongs entirely to thinking things, while extended things are nothing but mindless stuff, even if that stuff is intricately formed into clockwork or biological systems.

It is in the context of this strict dualism that Descartes expounds his concept of the human soul. In his Discourse on Method, Descartes concludes that his soul is: “a substance whose whole essence or nature consists only in thinking, and which, that it may exist, has need of no place, nor is dependent on any material thing” (Pt. IV). Thus a human soul is a res cogitans, a thinking thing, entirely independent of the physical world. As a result, Descartes arrives at the idea that the mind or soul is something “wholly distinct from the body” and “would still continue to be all that it is even if the body were destroyed” (ibid). Descartes further believes that in humans, the soul and body mysteriously combine to form a united thing (Meditations, 6.13); but nevertheless, subjective experience belongs entirely to the thinking soul and not to the body. From this, it follows that animals are unlikely to have minds: unless they begin speaking or philosophising, Descartes argues in his letter to More, we have no certain evidence that anything beyond mechanistic, physical motion is occurring in them. And since the mind is an entirely immaterial thing, the mere physical similarities between animals and humans tell us nothing about whether or not animals have minds like ours.

Cudworth, on the other hand, thought Descartes’ dualism was far too presumptuous. He devotes several pages of his ambitiously titled The True Intellectual System of the Universe to showing that Descartes’ concept of the soul does not fit with everyday experience. For one, if Descartes is correct that the nature of the soul “consists only in thinking”, where does it go when we are asleep? When not dreaming, a person in a deep sleep is not expressly thinking anything, just like any inanimate object. In order to maintain that a sleeping person has a soul by his definition of it, Descartes would have to be able to show that people are actually thinking even in the depths of sleep; that the souls of sleepers are “never so much as one moment without expressly conscious cogitations” (TIS, p.160). Otherwise Descartes would be forced by his own definitions to group sleeping people with animals and inanimate objects as purely material mechanisms. For Cudworth, such cases (he provides others; TIS, p.160-1), show that whatever the soul is, conscious thought is not essential to it (and we can reasonably assume, linguistic thought is certainly not).

Considerations like this lead Cudworth to a picture of the soul which is far broader than Descartes’. Rather than a perpetually thinking, immaterial mind, Cudworth indicates his concept of the soul by the various names he gives to it, such as “Life”; “Internal Self-activity”; “Internal Energy”; and even (at his most incomprehensible) “Vital Autokinesie” (TIS, p.159). It is this internal energy that differentiates living creatures – plants, animals, and humans (sleeping or not) – from lifeless matter.

Unfortunately for Cudworth, he founds this idea on an assumption now thoroughly disproven; namely, that all physical motion must be caused by some non-physical substance.

Cudworth thought that matter could not cause its own motion; that it “hath no internal energy, self-activity or life belonging to it” and as such, “is not able so much as to move it self” (TIS, p.163). To explain motion in the physical world, then, Cudworth posited another substance, independent of physical matter, and which must therefore be incorporeal, “which acts upon the matter and hath a commanding power over it” (TIS, p.28). It is this self-active substance, rather than thought or linguistic reason, that makes up Cudworth’s concept of soul. This deals neatly with problem of the sleeping human: a sleeping human might not be thinking, but she still breathes, and her heart still beats; she might even move herself in her sleep. So even if the ‘higher’ part of her soul that causes linguistic thought and reason is currently dormant, this ‘self-activity’ is more than enough for Cudworth to differentiate a sleeping human from a watch or a mannequin.

Cudworth’s assumption that physical matter cannot move itself is, of course, wildly mistaken. We know today that gravity, electromagnetism and chemistry all provide perfectly good physical explanations of motion, including that of plants and animals. But even if we reject Cudworth’s underlying assumption that physical motion must be caused by something non-physical, his idea of the soul as ‘Self-Activity’ is not entirely ridiculous, for it implies a moral distinction that Descartes mostly failed to make: a distinction between living, feeling agents and inanimate objects.

Puppies & Pebbles

In fact, Cudworth’s concept of the soul has two defining features. The first is self-activity – the ability of a thing to determine its own movement and action. The second is subjectivity, which always accompanies the most self-active beings like humans and animals, and even plants to a very small degree. Cudworth argued that in men and animals, the soul creates a “con-sense and consciousness, which makes a being to be present with it self, attentive to its own actions… to perceive it self to do or suffer, and to have a fruition or enjoyment of it self” (TIS, p.159). In simple terms, the more self-active something is, the more aware of its own suffering or pleasure it is, culminating in humans being entirely self-conscious. Even if his underlying metaphysical assumptions are mistaken, Cudworth is surely onto something here: vivid subjective experiences seem to occur only in agents, that is, in highly self-active beings like animals and humans. And in fact, nervous systems did only evolve as organisms became mobile – when they became animals rather than plants.

To see where Cudworth is coming from, compare a puppy and a pebble. Whilst the puppy grows and moves of its own accord, a pebble neither grows nor moves except when it is acted upon by external forces. True, you can’t have a conversation with a puppy (which is crucial for Descartes), but it still seems to subjectively feel things in the sort of way that we do and pebbles certainly do not. Unlike Descartes, then, who must sort puppies and pebbles into the catch-all category of ‘non-thinking things’, Cudworth can point to a meaningful difference between the two: a puppy has internal energy and life in it, which makes the puppy capable of self-activity and subjective experience, whilst a pebble does not. We might not use the same words, but we can’t deny that the puppy is indeed more ‘self-active’ and more a ‘subject’ than the pebble; it has more agency. Even if this has nothing to do with the puppy’s ‘soul’, there is certainly something, or some set of things, which constitute this difference between a dog and a rock. We needn’t stick to Cudworth’s disproven assumptions about an immaterial life-force to get to this conclusion; we could probably find a biophysical basis for the kind of ‘self-activity’ he is talking about it: perhaps it has to do with the sense organs and brain structures that pebbles lack and both puppies and humans have. But the crucial thing is that such ‘self-activity’, whatever it is based upon, allows us to make a meaningful distinction that Descartes did not, between non-human things which are living, feeling creatures and those non-human things which are not. Most importantly, self-activity provides the basis for a meaningful moral distinction between animals and inanimate objects lacking from Descartes’ thought.

The Moral Worth of Animals

To return to where we began: it seems far more wrong to throw a puppy over a cliff than it is to throw a pebble over. If we asked a child why this is so, they would probably respond, “Because a puppy is alive and a pebble is not!” In a way, this is precisely what Cudworth’s ‘self-active soul’ affirms, and what Descartes’ ‘rational thinking soul’ ignores. For Descartes, the defining activity of the soul is (rational) thought, and the only conclusive evidence of thought is speech. In the absence of speech there is no definitive evidence that animals have souls. And because Descartes’ dualism is so absolute, this effectively makes animals and rocks the same kind of thing: both are equally devoid of thought, and therefore they are both equally ‘soul-less’. Our moral responsibilities toward the two will not be radically different. Not so with Cudworth, who has already widened the idea of the soul to include sleeping and comatose humans; that is, to things which are living but which are not thinking. This means that even in the absence of linguistic thought in animals, Cudworth can, and indeed does, recognise a meaningful moral difference between animals and inanimate objects. This becomes clearest at a point in the True Intellectual System where Cudworth examines a famous Scriptural passage about the non-human Creation: “Because Creation itself shall also be delivered from the bondage of corruption… For we know that the whole Creation groaneth and travaileth in pain together until now” (Romans 8:21,22). For Descartes – who was a faithful Catholic – the Creation to be ‘delivered from travail’ is nothing but a senseless, mindless machine. But Cudworth points out, quite reasonably, that mere senseless matter cannot really be in pain in the first place: “In the generations and corruptions of senseless bodies… when for example, oil is turned into flame, flame into smoke… there is, I say, in all this, no hurt done to anything” (TIS, p.866). In other words, there is nothing for senseless matter to be delivered from, because it does not have any subjective experiences. Rather, Cudworth thinks this passage must refer to the parts of the Creation that actually need deliverance from pain; and thus he concludes that God’s New Creation “will not be made for the sake of the senseless matter… but only for the sake of men and animals, the living spectators and inhabitants thereof, that it may be fitter both for their use and delight” (ibid, my emphasis). For Cudworth then, animals are subjects who can experience both delight and pain in the same sense as humans, even though they cannot put those experiences into words. Furthermore, Cudworth’s exegesis of this passage clearly reveals that he saw animal suffering as carrying a moral significance that the destruction of other kinds of matter in motion does not.

Cudworth’s ideas were far more subversive in his time than they might seem to us today. In his intellectual biography of Cudworth, the late John Passmore noted that Cudworth’s philosophy was “regarded with suspicion, as atheistic in tendency” because “he blurred the sharp distinction, on which Descartes insisted, between the human mind and every other sort of natural entity” (Ralph Cudworth: An Interpretation, 1951). In simpler terms, Cudworth noticed and emphasised the animal in the human, and more importantly, the human in the animal; and he did so in an intellectual culture which angrily discouraged such blurring of human-animal boundaries. The result was a moral approach to animals that fits with our moral intuitions far better than Descartes’. For an ancient-minded mystic writing nearly two centuries before Darwin, that’s no small feat.

© Samuel Kaldas 2015

Samuel Kaldas is a postgraduate student at the University of Sydney, writing an MPhil thesis on Locke’s natural law theory. He wishes to thank Dr Anik Waldow and Balint Kekedi for helpful comments.

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