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Signs of Mind and the Souls of Beasts

I - Signs of Mind and the Souls of Beasts

How my soul, which I look upon to be an immortal Being in me, that is the Principle of thinking, should extinguish with my Body I cannot in any reasonable way of thinking conceive. But that it is immaterial appears hence. Vizt. that the immediate Actions thereof which are thinking have not the least affinity with matter, nor often do those Actions when exerted terminate in it. As when I think of time, or when I think this present thought which is my present subject, Vizt. that my soul is immaterial. And indeed most of those Ideas which the art of Logick in the whole Latitude thereof furnishes me withall are totally removed from matter, and yet are so necessary that unless I have them either by nature or art I cannot think true without them. If it shall be thought that whatsoever is must needs be material, and whatsoever is not so must be nothing at all: I would enquire whether by matter we do not understand that which is the Object of some one or other of our senses?95
With the rejection of scholasticism and the emergence of new philosophies of nature, from corpuscularianism to Cartesian dualism, established doctrine about the kind of relation that bound humans to other living creatures underwent significant upheavals in the period of the Scientific Revolution. It is impossible to recount a history of the relation between body and mind at that time without considering the shifts in the understanding of what sort of thing the human body was, given what sort of capacities humans had and, notably, given their ability to speak. Metaphysical concerns about the need to preserve the exceptional status of human beings within the created realm were inseparable from considerations about the characteristics, capacities and limitations of language, given the widespread belief that language was unique to humans and a manifestation of higher reason. In this section, we look at post-Cartesian ideas about the fate of human reason. We do so by considering the relation of reason to the definition of language among both English natural philosophers and French Cartesians, in Chapter 1; through the debates, following Descartes’s beast-machine thesis, about the nature of animal minds in relation to human language and reason, in Chapter 2; and through a study of discussions and polemics on the nature of the capacities of beasts, in Chapter 3.

The changes which took place during those years did not consist in a clean, easy break from previous doctrines. As this presentation to Part I explains - especially through the earlier, but central case of Harvey and his dealings with Aristotelianism - the past was still present, and problematically so, within the very issues which would seem most pointed during the second half of the century.96 According to the tradition bequeathed in various forms to the Renaissance via scholasticism and Galenism,97 human beings belonged to the ‘great chain of being’: life and its manifestations were explainable according to different sorts of souls which were all related to one another. The basic model was a tripartite soul. Humans shared with beasts a sensitive soul, responsible for perceptual and motive faculties, and with both beasts and plants a vegetative soul, responsible for the faculties of growth, nutrition and generation. In Aristotle’s view, some aspects of the higher, intellective soul of humans also belonged to beasts; but deliberative reason was the prerogative of man alone,98 in whom there was, as he wrote, ‘a part of the divine’.99 The faculties of these three souls constituted the psyche, usually translated generically, as soul, anima in Latin, which for Aristotle was the substantial form100 of the body - the substance, ousia,101 in virtue of which matter manifested itself and had its identity. In his words, in De anima, the soul was ‘the cause and principle of the living body’,102 responsible for self-nutrition, movement and perception.103

Previously, the Greek concept of psyche had always denoted the condition of being alive.104 For Plato too, as he wrote for example in the Phaedrus, ‘a body deriving its motion from a source within itself has a psyche’,105 which he thought was necessarily uncreated and immortal, and separate from the body. Aristotle also saw the soul as incorporeal. But he could not accept the Platonic notion that it was separate from the body: it was because of the very ‘partnership’ of soul and body, he wrote, ‘that the body acts and the soul is affected, that the body comes to be moved and the soul produces motion’.106 He sought to explain the natural world in terms of its finality, accounting for living organic matter in terms of its intrinsic functions107 and of what the various bodies were designed to accomplish, given their shape, form, qualities and so on; so, he held ‘natural bodies’ to be the ‘soul’s instruments, those of plants in just the same way as those of animals’.108

The Baconian ‘new science’ was characterized by the programmatic, although never simple rejection of this teleological account of the physical world - long-lived but too rigidly dependent on Aristotle’s notion that ‘in some way the body exists for the sake of the soul, and its parts for the sake of those tasks for which each grew’.109 The data of physics and natural history were now to consist of quantitative rather than formal and qualitative analyses of matter,110 and of the empirical observation of natural phenomena; organic processes were now to be identified inductively rather than deductively. Verbal descriptions would have to be clear and scholastic formulations shunned;111 but reality itself need not be neat. In the second of his momentous essays on the circulation of the blood,112 William Harvey (1578-1657) declared, against those ‘who repudiate the circulation because they see neither its efficient nor its final cause’, that the ‘facts manifest to the senses wait upon no views’ and ‘the works of Nature upon no antiquity: for there is nothing older or of greater authority than Nature’.113 This did not mean that Aristotle should be dismissed. On the contrary, Harvey referred to him frequently, for example in his description of the formation of the heart in the chick and human embryo.114 Rather, the observation of nature and the search for concrete mechanisms would have to take precedence over those scholastic formulae which favoured formal and final causes, because ‘explanations in terms of forms’115 began to look unsatisfactory, and because the use of teleological explanations became redundant.

Moreover, Aristotle himself most probably had performed dissections,116 and his resulting observations were present throughout his writings. In his first essay on the circulation of the blood, Harvey also quoted approvingly Aristotle’s words in De generatione animalium to the effect that: ‘Faith is to be given to reason if the things which are being demonstrated agree with those which are perceived by sense: when they have become adequately known, then sense should be trusted more than reason’.117 But in the absence of comparative dissections such as those Harvey was able to practice, the available conclusions had been limited and remained stuck in time in the form of ‘a universal syllogism on the basis of a particular proposition’.118 No revision was possible without further facts, gathered from observation, dissection and vivisection.

Harvey’s precise but respectful revision of established doctrine thus invoked the authority of observation to ground a new account of blood circulation which he eventually would explain in terms of its relation to heart function, misunderstood until then, as he wrote, and fixed in the erroneous description of the septum between left and right ventricle as porous. The perpetuation of error had been caused in part, he thought, by the Galenic emphasis on ‘the close connection of the heart and the lungs in the human subject’,119 where the lungs had been understood to act as the refrigerator of the innately hot heart. Instead, the heart was, in Harvey’s words, ‘the starting point of life and the sun of our microcosm’, ‘the tutelary deity of the body, the basis of life, the source of all things’,120 present in the embryo before either liver or brain, although probably not before blood. The view that blood in fact circulated between arteries and veins via the heart,121 moreover, triggered a need to revise some key features of the Galenic edifice, which relied on the vital spirits that coursed through the organism. In the second essay on the Circulation of the Blood, Harvey discussed the nature of the spirits contained in the blood (itself, as he showed, contained in the veins), stating that ‘there are many and opposing views’ regarding what spirits were and regarding ‘what is their state in the body, and their consistence, and whether they are separate and distinct from blood and the solid parts, or mixed with these. So it is not surprising’, he went on, ‘that these spirits, with their nature thus left in doubt, serve as a common subterfuge of ignorance’.122 Those half-material, half-spiritual organisms had always acted as the key to the connection between sensation and cognition, emotion and movement. Until Harvey, they were concocted by cardiac heat123 and expelled by the aorta, from where they were distributed throughout the body via the arteries. But these originally Galenic spirits remained very much alive in some form or another as key explanatory structures for the functioning of sentient, cognizant living creatures, beyond Harvey, beyond Descartes and well into the modern era.

In the Galenic scheme, which was also the medieval one, the liver’s ‘temperament’ was the seat, or form, of Aristotle’s nutritive and vegetative soul (and of Plato’s concupiscible soul). As for the heart’s ‘temperament’, it was the irascible form of the soul.124 Both the irascible and the concupiscible souls, along with the imagination, partook of the sensitive soul, and, at least on the Thomist version of this Aristotelian model, all human passions belonged to either one of those.125 The brain was the seat of the rational, or intellective, soul: the two anterior lateral ventricles housed imagination, the middle ventricle housed thought, the posterior ventricle, memory. According to this scheme - some of whose terminology at least was still in use throughout the seventeenth century and beyond - the blood and its contents, broadly speaking, were expedited from the liver to the brain via the heart. Some of the vital spirits transported by the blood would be refined by the cerebellum into smaller animal spirits, responsible for the transmission of sense-perceptions to the sensus communis, the seat of common sense, separate from reason and will.126 Formal explanations - shaped first in an Aristotelian mould and reworked by medieval Arabic commentators and Renaissance humanists - both accounted for and implicitly assumed a continuum between organ and cognition, between blood and spirit. What is striking, and commonplace among historians of science but nonetheless important, is that the shift in method, in place already in the early part of the century, did not entail even by the latter part of that century a shift in vocabulary or in assumptions about the mutual dependence of physiology and theories of human nature.
Descartes (1596-1650) is a prominent instance of this lag between method and concept. His mechanistic account of matter entailed the idea that motion in space - including the motion of heart and blood - was due to mechanical action. While, as we shall see further on, the programmatic structure of the arguments he used to demonstrate the truth of his picture of the organism was itself novel, his physiology nonetheless rested, within the realm of natural philosophy, on a Galenic scheme.127 He thus believed that the body’s motive faculties were taken care of by Galenic animal spirits, the subtlest parts of the blood, which travelled from the arteries to the nerves and muscles via the ‘pores’ of the brain, causing us to perceive, feel, move and remember. As he recounted in the Discours de la méthode and in L’homme, the spirits were propelled by the heart’s heat and changed according to the blood’s composition, determining passions and bodily states.128 The movement of the blood, due to a combination of heat and fermentation, was the cause of the heart-beat, itself caused by the heart’s heat, ‘a fire without light’.129 Once in the brain, the animal spirits passed through the ventricles and entered the pineal gland, or conarium, from where they kicked into action. Via the nerves, they determined muscle flexion and distension, the cause of movement; and via the same nerves, they affected the brain according to the part of the body they were coming from, causing all sense perception and all sensation.130

Georges Canguilhem made a good case in 1977 for claiming that Harvey’s theory of heart-beat was too incompatible with a mechanistic account of its motion for Descartes to dare accept it.131 The heart could not be a muscle, as Harvey had claimed (against Galen), for that would have meant that the animal spirits it produced would also have to travel to it in order for it to function. Clearly this was not possible, and it was inconceivable to picture the heart as a pump,132 as Harvey had done. Better, in the Cartesian scheme, to retain the kind of account which allowed for clear, mechanical explanations of all possible emotions and ailments.133 The organ-cognition, blood-spirit continuum thus remained with Descartes, but as a mechanical chain, and with the addition of the pineal gland as the “operations headquarters” of the soul. Galen would continue to rule in medical practice even as Harvey’s theories begot heirs. Animal spirits thus continued to explain the workings of living organisms; and Aristotelian finalism continued to exert its hold on medical theory.

Thomas Sydenham (1624-1689), for example, London’s most respected physician in the 1660s and 70s, friend of Robert Boyle (1627-1691) and John Locke (1632-1704), preferred observation to text books and received ‘anatomie’. But his faith in observation was sustained by the belief ‘that there is a most perfect and exquisite Order in the severall natures of the world, fully conducing to the preservation of their individual Beings, and to the propagation of their kinds’.134 This determined the order of causes; so, ‘it cannot be, but if I shall be shipwrackt at sea I must needs be drowned’. And yet, this order was such that ‘to the preserving me from this mischief [of dying at sea] he [God] may be pleased so to dispose the previous Circumstances of my Will and other things, as to prevent my going to sea, and so in this and in other things he may hinder the Occasions leading to my destruction’.135 Freedom of will and divine foreknowledge could coexist.136 On the one hand, there was a causal order in the world, over which we had no control; on the other, the causal order was such that God could know everything about it. To know God was the only way of having control over events. Sydenham contrasted the lowly soul we shared with brutes with the higher, intellectual, immortal soul, which alone was able to worship God. Our position with regard to the ‘Lawes of nature’ was such that, while these laws were ‘written on our minds’, our sensuality might ‘deface’ them.137 We were ‘partly rational and partly brutal’, but it was possible to live beyond our passions, however ‘riveted’ into our nature these laws of nature (which included ‘self preservation’) were.138 Here, then, was a doctor holding on to finalism within a dualist framework - arguing that we are such that we do what we are made to do, contemplate God - while also advocating that we should conceive of the human body as an elaborate organism not explicable in terms of forms.139 Robert Boyle, too, believed that ‘all consideration of final causes is not to be banished from natural philosophy; but that is rather allowable, and sometimes commendable, to observe and argue from the manifest uses of things, that the author of nature pre-ordained those ends and uses’.140

Meanwhile, treatises on natural theology such as that of the botanist John Ray (1628-1705) could fill the explanatory gap left by mechanistic accounts of living matter:141 Ray attacked the Cartesians or ‘Mechanic Theists’ and pointed to the inability of the mechanical account of matter in motion to explain the variety, formation and organisation of animals’ bodies.142 As we shall see throughout this section, a commitment to new explanatory schemes was posing problems to the common-sense assumption, previously protected by scholastic structures, that all living creatures were equipped with some sort of mind.143 Accounts of the biology of humans and beasts had them both meet undercover, so to speak, disguised as ‘automata’ by Descartes and later Cartesians. Materialistic explanation was potentially menacing now that the hierarchy of souls, disbanded along with the scholastic heritage, no longer guaranteed the preeminence of man-as-animal among fellow animals - a preeminence salvaged only through the claims of teleology. The availability of mechanism and Gassendist atomism as explanatory structures led to doubts that the biology we shared with animals signified anything about the nature of our souls; the reality of both man and beast might lie hidden from the senses. On the other hand, it became possible to say that, since human thought and voluntary action partook of the immaterial soul substance, involuntary action was a matter of biology, just as it was for animals. The relation between will and biology, however, remained unclear.

We begin this section with verbal knowledge - theories about the nature and truth-value of language and its relation to ideas in the human mind; and end it with questions about ‘natural’, innate knowledge - theories aimed at establishing the respective roles of reason and instinct in guiding human and animal action. On the way, we hear proclamations about virtue and reason, loud appeals to the fate of the human soul and various logical or ethical formulae, all employed in arguments against, as well as for, the notion of an animal soul, mind or thought. Together, these discussions contributed to bringing to the philosophical fore a good deal of puzzlement about the function of a rational faculty in creatures such as ourselves, whose bodies functioned like those of animals, according to the laws of nature - of matter in motion, mechanical action and blood circulation - but whose souls had to remain immortal. The efforts to map the human mind’s hidden contents in terms of our capacity for symbolic representation are presented here as one manifestation of this perplexity about reason. These efforts included the creation of a language for the deaf-mute, along with the quest for a universal language; and they were related to the establishment of criteria for the practice of natural philosophy, as well as to debates on ideas and thought in French Cartesian circles. It appears that questions regarding the nature of language and its acquisition could not be set apart from those regarding the nature of thought; but neither could questions about the nature of reason be formulated without language. It is thus with this puzzle about the place of language in the natural world that we open our enquiry.
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