'I Follow Aristotle': How William Harvey Discovered the Circulation of the Blood

Andrew Cunningham

• Publisher: Routledge
• Year: 2022
• ISBN:
  9781000610796
• Edition: 1
• Topic: History
• Subtopic: World History
• Index: History

This book presents a new interpretation of how and why the discovery of the circulation of the blood in animals was made. It has long been known that the English physician William Harvey (1578–1657) was a follower of Aristotle, but his most strikingly 'modern' and original discovery – of the circulation of the blood – resulted from Harvey following Aristotle's ancient programme of investigation into animals. This is a new reading of the most important discovery ever made in anatomy by one man and produces not only a radical re-reading of Harvey as anatomist, but also of Aristotle and his investigations of animals.

1 Aristotle’s animal and the question of the soul

DOI: 10.4324/9781003247616-3

As can now be seen from my Prologue chapter ‘Nine years and more’, my story about how Harvey discovered the circulation of the blood begins by privileging Harvey’s own claim, ‘I follow Aristotle’. My argument then starts with Fabricius in 16th-century Padua trying to revive and to continue practising Aristotle’s investigations into animals. Harvey, in turn, takes up this same practice of investigating animals, and takes things further than Fabricius had done. Finally I claim that, by following Aristotle both as practitioner and theorist, Harvey finds himself investigating an anatomical area that no-one – not even Aristotle, not even Fabricius – had investigated before, that is the heart and blood vessels of live animals (all animals, not just humans), but doing so without exploring the lungs or other respiratory organs (as all anatomists, intent on humans, had done before him). By complete immersion in this project over a number of years, by creating new experimental procedures, by dogged work and persistence, by refusing to be put off by the extraordinary findings he was making, Harvey discovered – not willingly, not with any sense of triumph – that the blood circulates continuously in animals, including man, while they are alive, and that when the heart stops pumping the blood then the animal dies.

‘I follow Aristotle’, Harvey wrote. But what Aristotle is this? And this Aristotle, what is his project of investigating animals? It is not an Aristotle we are familiar with today, nor are we familiar with this project of investigation by Aristotle, despite generations and generations of scholars exploring and discussing his work.

The standard explanation from Antiquity of what Aristotle was doing with respect to animals, and which is recorded in his animal books, comes from the elder Pliny’s Natural History (Naturalis historia), written in the mid-1st century A.D. Will this be of any help as we try to answer our question about the identity of Aristotle’s project in investigating animals? Pliny is talking about lions when he writes:

Aristotle … a man whom I cannot name but with great honour and reverence, and whom in the history and report of these matters I mean for the most part to follow. And in very truth King Alexander the Great, of an ardent desire that he had to know the natures of all living creatures (naturas animalium), gave this charge to Aristotle, a man singularly accomplished with all kinds of … learning, to search into this matter, and to set down the same in writing: and to this effect commanded certain thousands of men, one or other, throughout all the tract as well of Asia as Greece, to give their attendance and obey him: to wit, all Hunters, Falconers, Fowlers, and Fishers that lived by those professions: Item, all Forresters, Park-keepers, and Wariners: all such as had the keeping of herds and flocks of cattle: of bee-hives, fish-pools, stews, and ponds: as also those that kept up fowl tame or wild, in mew: those that fed poultry in barton or coup: to the end that he should be ignorant of nothing in this behalf, but be advertised by them, according to his Commission, of all things in the world. By his conference with them he collected so much, as thereof he compiled those excellent books de Animalibus, i.e. of Living creatures, to the number almost of 50. Which being couched by me in a narrow room and brief summary, with addition also of some things which he never knew, I beseach the Readers to take in good worth: and for the discovery and knowledge of all Natures works, which that most noble and famous King that ever was desired so much to know, to make a short start abroad with me, and in a brief discourse by mine own pains and diligence digested, to see all.¹

So Pliny here ascribes the whole project to an initiative of Alexander the Great ‘of an ardent’ – if unspecific – desire that he had to know the natures of animals [so in the Latin, all living creatures in the English], who put Aristotle in charge of a grand investigative programme with thousands of men to work for him. Pliny gives no timing for this project so scholars have chosen, according to their lights, to place it at the beginning of Aristotle’s career, or in the middle, or at the end, whichever best suits the story they want to tell about Aristotle’s work.² Pliny here also indicates that his own project in the Natural History is of a similar kind and with similar goals. For, whatever source Pliny had for this story, he is clearly describing Aristotle as an early Pliny:

As touching myself (forasmuch as Domitius Piso says, That books ought to be treasuries and store houses indeed, and not bare and simple writings) I may be bold to say and aver, That in 36 books I have comprised 20000 things, all worthy of regard and consideration, which I have recollected out of 2000 volumes or thereabout, that I have diligently read … and those written by 100 several elect and approved authors (Dedicatory Epistle to Vespasian, not paginated).

Where Aristotle supposedly had thousands of men to collect varied and unspecific information, Pliny has had 2000 volumes as his sources for his factual and imaginary stories. I think that Pliny’s account of Aristotle’s animal project can be trusted about as much as Pliny’s own naive stories of elephants which speak Greek and climb trees upside down (Natural History book VIII, 1.3). Even if it is true, Pliny’s account of Aristotle’s project is so imprecise with respect to motivation, or to what information was to be sought, as to be of no use to us at all. So let us put this hoary old story aside and begin again. Our primary source has to be Aristotle himself, not some gullible fantasist such as Pliny writing several centuries later. It is, however, the case that Aristotle’s animal books record and include the observations of very many people over a very long time, all brought together to serve as data for Aristotle’s own questions.

So, what had Aristotle been doing when he was investigating animals, back in the 4th century B.C.? Why had Aristotle turned to them in the first place as an object of enquiry? For he knew of no predecessors in this enquiry, and we know of no systematic investigations into animals in the Greek tradition before Aristotle either. What was his enquiry about? What was he looking for? What questions was he asking? What kind of answers was he satisfied with? How did he demarcate his area of enquiry: precisely what did he take as his material for investigation? And quite how did he go about it?

Modern scholars of Aristotle’s animal books have investigated virtually none of these questions. For they have worked with the assumption that they already know what Aristotle was doing in his investigation of animals: they take him to have been practising modern disciplines such as ‘biology’, ‘comparative anatomy’, ‘taxonomy’, ‘embryology’ and so forth (see Chapter 9 below). But we need to treat it not as a settled, but as an open question what Aristotle was up to: and to discover the answer to this we need to listen to what Aristotle himself said about what he was doing and why he was doing it. There can be no better witness than Aristotle himself to the identity and coherence of his own activity.

Today we think of Aristotle as a philosopher who could wear many hats: and we do not remark that the extension of his concept of philosophy and of the role of the philosopher is matched by no modern category of knowledge and by no modern scholar – and indeed is not even captured by all the faculties of a modern university and all its academics, taken together. In fact, the modern discipline of philosophy is itself a creation of the 18th and 19th centuries. The point, concerns, topics and identity of old philosophy were all transformed and reshaped then, and were greatly restricted compared to their former range and extent. The modern philosopher was now obliged to yield his expertise with respect to Nature to that new person, the scientist. The new philosopher now had to pursue his philosophy not in the world but in the ivory tower of academia: philosophy was no longer to be the pursuit which enabled one to live the life of the good man, but was restricted to a set of discrete topics for discussion and argument.

In order to appreciate Aristotle’s view of the role of the philosopher and of the goals of philosophising, and of his view of the role of the study of animals, the first thing we have to do is to abandon the modern discipline boundaries and definitions. For it is only our commitment to these which leads us to characterise his animal books currently as ‘biology’ and so on, and therefore to contrast, oppose or even seek to reconcile them with his supposedly distinct and supposedly contrasting ‘philosophical’ works. Our discipline of philosophy has no role for the systematic study of animals. But it will become clear that Aristotle’s philosophising was undertaken in order to understand the nature and functioning of the soul, and that this meant that an integral and crucial part of philosophy had to be animals. Only when we can see the animal books as an integral part of Aristotle’s particular view of what philosophy is and how it should be lived and practised, will we have gone some way to understand them.

Anatomising is a means to an end, not an end in itself. The anatomist engages in anatomising in order to answer questions he or she has in their mind. The questioning mind guides the knife in the hand. The anatomist may wish to discover what kinds of different material the human, animal or plant body is made up of. Or he may wish to know how particular organs within the body work or carry out their functions, or even what these functions are. Or she may be inquiring about the similarities or differences between different animals, maybe asking why they exist, and perhaps even asking whence these similarities or differences derive. Or they may be seeking to find out how one complete animal or plant produces another like itself.

So: anatomy is a practical and empirical pursuit, aimed at acquiring theoretical knowledge. Without his knife in his hand, the anatomist is helpless: he cannot be an anatomist unless he cuts up and explores, as at least one part of his investigative procedure. But equally, without thinking and reflexion, the anatomist gains no more knowledge through all his cutting-up than the butcher has. This theoretical, contemplative, dimension of anatomising is what distinguishes the anatomist from the slaughterer, butcher, cook or huntsman, who seek knowledge of the insides of animals for practical purposes, such as preparing meat for table. While anatomical knowledge can certainly be put to practical use in other contexts, such as medicine and surgery (two of the disciplines in respect of which we usually think about anatomising), and this ultimate practical use may be the reason why any given individual engages in anatomising, yet in itself anatomical knowledge is not practical but wholly theoretical. This characterisation of anatomy applies equally to all the different anatomical projects that there have been over the centuries.

It is clear that Aristotle did actually perform anatomy, asking questions about the nature (and natures) of animals and their organs, questions which could only be answered by employing the manual practices of dissection and vivisection. The term ‘anatomy’ is ancient Greek in origin (rather than modern-style Greek, like ‘biology’). There is extensive evidence in the animal books that Aristotle had personal experience of the dissection of a wide range of animals. Aristotle repeatedly refers his readers to his own (now lost) book, Dissections (or Anatomy). In the Parts of Animals, for instance, when speaking of the parts which pass the food, Aristotle writes:

The mouth, then, having done its duty by the food, passes it on to the stomach, and there must of necessity be another part to receive it in its turn from the stomach. This duty is undertaken by the blood-vessels, which begin at the bottom of the mesentery, and extend throughout the length of it right up to the stomach. These matters should be studied in the Dissections and my treatise on Natural history [i. e. the History of animals].

(650 a 28–32)

When discussing the blood vessels, he writes: ‘For an exact description of the relative disposition of the blood-vessels, the treatises on Anatomy and the Researches upon animals should be consulted’ (668 b 28–31). Similarly, when discussing the lobster, Aristotle writes, ‘For an account of every one of the parts, of their position, and of the differences between them, including the differences between the male and the female, consult the Anatomical treatises and the Inquiries upon animals’ (684 b 2–6). And everywhere in the Parts of Animals there is material presented which could only have been established by dissection; for instance: ‘In all cases that we have examined the heart is boneless, except in horses and a certain kind of ox’ (666 b 18–20). In other treatises linked to the animal books too there are direct references to dissection as in On Respiration, for example, and On Sleep. It is also clear that Aristotle had prepared diagrams for his Dissections. Speaking of the cuttlefish in History of Animals, for instance, Aristotle writes: ‘The cuttlefish has two sacs and numerous eggs in them, like white hailstones. For details of the arrangement of these parts, the diagram in the Dissections should be consulted’ (525 a 6–8).

Anatomy has two interdependent facets: manual (dissection) and mental (rational and contemplative). We have just seen that Aristotle engaged in the manual practice of dissecting animals. But why? What were the rational and contemplative grounds for him doing so? Usually this question would not arise in our scholarly work on him. And if the question were raised, it would seem like a question whose answer is self-evident: for we would assume that Aristotle obviously anatomised animals because in conducting the work recorded in the animal books he was being a biologist (or some other kind of modern investigator). In such a role or roles of course he would have anatomised animals. How else could one sensibly be a biologist and so on? But as that was not – could not have been – the case, the question can indeed be asked: what reason did Aristotle have for engaging in such systematic dissection of animals? – for it is not the sort of thing one engages in for no purpose.

In seeking to recover what Aristotle’s object and project of investigation was with respect to anatomy, let us use Aristotle’s own words as much as possible. And let us start our investigation of the nature of this project at the same point that Aristotle starts his own exposition of it – and by this I mean the beginning of Aristotle’s argument about the study of animals, which may or may not be chronologically the earliest of his works in this area.³ This starting point is in the book On the Soul, known to scholars for centuries under its Latin title, De Anima.⁴ We need to read it as the necessary preliminary to the animal books. Indeed it is more than a preliminary: it is the book whose theme and thesis called into existence the animal books themselves, and the work recorded in them.⁵

A work on the soul ought to seem to us to be a mighty odd place for anyone to begin the exposition of a project on anatomy. In the modern way of going about things, there is no relation between the ‘soul’ and the enterprise of seeking anatomical knowledge. Yet Plato, Aristotle’s own teacher, talking in the Timaeus about the human body, had described it as divided into certain regions which correspond to the nature and needs of the soul, and talked of the body as ‘the vehicle of the soul’. Indeed it can be claimed that the philosophical projects of each of that great triad of Athenian philosophers – Socrates, Plato and Aristotle – were soul-centred, that their respective philosophical systems are about the soul. Scholars have of course been right to point out the great differences between the outlooks of Socrates on the one hand, and his pupil Plato on the other; and between Plato on the one hand, and his pupil Aristotle on the other: there are indeed differences, and they are highly significant. Yet the things that Socrates, Plato and Aristotle disagree on, in successive generations, are the same things. That is to say, they agree on what the enterprise of philosophy is about: it is about the human soul gaining wisdom and understanding. They disagree on precisely what kind of thing the human soul is, and hence on what kind of wisdom and understanding it can properly acquire and how it acquires it.

In the modern world, however, we have divided up the topics of knowledge in a way which would have made no sense to Plato or Aristotle. In the first place we take the study of the ‘soul’ (insofar as it is thought to exist at all) to be the province of only one branch of knowledge: theology/religion. Similarly we have put just some of the concerns of the Greek philosophers into the subject-area that we now call ‘philosophy’: logic, metaphysics, epistemology, ethics, aesthetics. And others of their concerns we have placed in our subject-area, ‘science’: anatomy is one of these, which we count to be part of ‘biology’, itself regarded by us as a part of science. These subject-boundaries we work with are antithetical to the Greek philosophical enquiry. The soul and anatomy, which Aristotle studied as one, we have not only put into different departments of knowledge, but into ones to which we accord different statuses: theology/religion for us deals with ‘revealed’ truth, while science we take to deal with ‘objective’ or physical truth.

The defining of ‘soul’ as something which is the concern of theology/religion comes from Christianity being our paradigm of what a religion is. Yet ‘soul’ became a central concern of Christianity in the first place because of the influence on Judaism of Greek ways of thinking. Soul as the true man, or what-makes-a-man-what-he-is; the soul as something immortal; the soul as an entity separate and separable from the body; the soul as something implanted in the human body before birth; the soul as something which ‘ascends’ out of the body after death. All this is Greek and common to Socrates, Plato and Aristotle. But we can also find all this about the soul in certain books of the Old Testament and many books of the New Testament because there was an extensive historical encounter of Judaism with ‘Hellenism’ – with, that is, the legacy of Socrates, Plato, Aristotle and others, and most especi...

Table of contents

• Cover Page
• Half Title page
• Series Page
• Title Page
• Copyright Page
• Dedication
• Contents
• List of figures
• Preface
• Prologue ‘Nine years and more’: An overview of the story
• Introduction
• 1 Aristotle’s animal and the question of the soul
• 2 Aristotle On the causes of the parts of animals
• 3 Aristotle’s animal in Padua: The anatomical investigations of Fabricius
• 4 William Harvey: Pupil, physician, professor
• 5 William Harvey, searcher into the vegetative soul
• 6 ‘The wonderful circulation of the blood first found out by me’
• 7 Method and experiment
• 8 ‘The anatomy of the blood’: The blood as a new research object
• 9 Precursing Aristotle: Why and how did we lose this Aristotle?
• 10 Harvey and his historians: Why and how did we lose this Harvey?
• Appendix English or Latin?: A note on the editions and translations of Harvey’s published works.
• Index