Circulation

AN INDEFATIGABLE EXPERIMENTER, with a rare genius for devising and interpreting ‘trials’, it is hardly surprising that William Harvey has often been described as a practical counterpart of Francis Bacon (1561–1626), the great philosopher of empiricism. ‘Bacon’, one of Harvey’s twentieth-century biographers wrote, ‘laid down the rules for the collection of facts and for inductive methods of thought, but he did not sufficiently realize the value of experiment. Harvey by his example taught the correct place of experiment. The sequence was careful observation, thoughtful deliberation, appropriate experiment, and further consideration upon its results. This has ever since been the model for research students.’

Conveniently for those who make such claims, Bacon was one of Harvey’s patients during the late 1610s and early 1620s. Harvey was rather wary of the super-subtle thinker and Machiavellian politician: Bacon’s ‘delicate, lively, hazel eie’ reminded him of the ‘eie of a viper’. It is likely that they clashed occasionally on medical matters. Bacon had his own ideas about how diseases ought to be treated, and rarely followed his doctor’s orders.

Portrait of Francis Bacon. Formerly King James I’s Solicitor General, Attorney General and Lord Keeper, Bacon was elevated to Lord Chancellor in 1618 and given the title Baron Verulam.

Bacon was sorely afflicted with gout throughout his adult life: ‘never beggar’, he would wail like a titan in pain, ‘had the gowte but me’. He probably called on Harvey during one of his many attacks. A veteran of the malady himself, Harvey was certainly qualified to suggest a number of treatments. ‘If you would be rid of the gout’, the physician told his patients, ‘you must neither drinck wine nor any strong drinck; you must eate but once a day, and that sparingly too.’ Bacon probably demurred, as he believed that a combination of plasters, poultices and baths would see off an attack. It seems unlikely, though, that his proud physician would have obliged him by carrying out the proposed treatment.

Bacon had a low opinion of physicians generally, dismissing most of them as charlatans. In his famous treatise on education The Advancement of Learning (1605), he argued that medicine had progressed little, if at all, in the modern period. It relied too heavily on authorities, when inductive investigation was required. ‘Men have withdrawn themselves too much from the contemplation of nature, and the observations of experience, and have tumbled up and down in their own reason and conceit … they [have been] made fierce with dark keeping.’ Bacon proposed a new philosophic system, based on the empirical examination of nature. ‘All depends on keeping the eye steadily fixed on the facts of nature, and so receiving their images simply as they are.’

‘My way of discovering sciences [i.e. knowledge]’, Bacon wrote, ‘performs everything by the surest rules.’ These rules included the compilation of detailed statistical tables relating to all the manifestations and variations of a particular phenomenon – for example, that of heat. Surveying the mass of particular instances garnered in these tables, Bacon believed that he was in a position to isolate what was essential about a phenomenon. By a process of induction, he could, he argued, also arrive at general hypotheses regarding it. These hypotheses could in turn be tested by experiments ‘skilfully and artificially devised for the express purpose of determining the point in question’.

Bacon criticized thinkers such as Plato for ‘intermingling’ ‘[natural] philosophy with theology’, yet the main target of his prose polemics was Aristotle. The Greek philosopher’s ‘four causes’ of natural phenomena should, he argued, be dispensed with, especially the final cause which confounded men’s minds by focusing on the ultimate purpose or the ‘why’ of phenomena. This was something that, in his view, simply could not be fathomed – nor did it need to be.

Bacon claimed that Aristotelian syllogisms were flawed too, being based on ‘propositions which consisted of words’ – that is the ‘symbols of notions’. The problem was that ‘if the notions themselves are confused there can be no firmness’. Moreover, syllogisms encouraged men to argue from a universal principle (i.e. ‘All men are mortal’) to a particular (i.e. ‘Socrates is a man’), when what they ought to be doing was using particular instances as stepping stones towards general principles. Aristotle was, Bacon complained, liable to entangle men’s minds in a net of words and propositions; this rendered them pedantic and sluggish when it came to identifying facts. The Greek’s philosophy was an inadequate tool for ‘enquiring into truth’, utterly ‘useless for the discovery of knowledge’.

Bacon saw some promise in the innovative ideas and methods of contemporary natural philosophers such as Galileo, who had been Padua University’s professor of mathematics during Harvey’s time there. Like Bacon, Galileo believed that natural philosophy ought to be based on ‘sensory experience and necessary demonstration’ rather than an abstract exploration of the ‘why’ of things. Bacon admired Galileo’s experiments to establish the precise measurement of the primary qualities of external bodies – their size, shape, quantity and motion – the Italian maintaining that these were the only qualities inherent in objects; secondary qualities, such as colour or scent, existed partly in men’s minds.

Yet even the great Tuscan was found wanting by Bacon, for the limited scope and number of his experiments. He complained that Galileo’s ‘trials’ stopped ‘with [a] few discoveries’ – that is, after his tests had settled a theory to his satisfaction – ‘and [so] many other things equally worthy of investigation are not discovered by the same means’. Galileo still dedicated too much time to imaginative philosophical thought for the English empiricist. ‘Individual excellence’ or ‘genius’ was, Bacon held, far less important than the establishment of a broad, state-funded programme of experimentation into all natural phenomena, carried out by humble artisans who would use their eyes and hands as much as their minds. The knowledge accrued from such a project would, Bacon prophesied, give man dominion over the entire natural world, as well as the power to harness its energies and resources.

Bacon believed that technological advances such as printing, gunpowder and the compass had already ‘changed the whole face and state of things throughout the world’; the exploration of distant lands beyond Europe had also revealed new wonders. And there were still so many secrets to uncover, myriad domains to map and master, numerous instruments to devise, countless natural forces to manipulate and exploit. Through induction and empirical investigation man would be restored to the pristine condition of perfection and potency he had enjoyed before the Fall; in action he would be like an angel, in apprehension, like a God!

Over the course of his private research, Harvey tested various hypotheses, such as the forceful systole, by devising experiments on human cadavers and living animals, and observing the results. His ‘trials’ revealed a number of anomalies in traditional notions of the function of the heart and the movement of the blood, and he appears to have formulated alternative theories that were in better keeping with his findings.

At first glance, Harvey’s project would appear to have been thoroughly Baconian, as does his achievement in undermining a 1,500-year-old theory through empirical investigation and the discovery of anomalous facts. Harvey overpowered tradition, it seems, because he was an empiricist, no longer content to rely on books, but determined instead to investigate the body as it really is. When discussing his methodology, Harvey always emphasized the importance of ocular testimony, the reading of books being less important than ‘finding out the nature of things by the things themselves’. Harvey’s innovative circulation theory, it has often been argued, emerged organically from a revolutionary Baconian method.

Harvey’s methods and philosophy were, however, utterly different from Bacon’s. The empirical aspect of his research programme, like most of its other facets, was derived from Aristotle, the ‘general’ whose authority carried such weight with the Englishman that he ‘never did think of differing from him inconsiderately’.

It may have been at Padua that Harvey had learned of Aristotle’s theories regarding the role of particulars, and empirical enquiry, in the search for universal philosophical knowledge. These theories were far more subtle than Bacon’s polemics suggested. ‘Singulars are to us more known’, the Greek philosopher wrote, ‘and are the first to exist according to the information of sense, for there is nothing in the understanding which was not first in the sense … and we more readily define singulars than universals, for there is more equivocation in universals; whence it is advisable to pass from singulars to universals … It is impossible to have universal theoretical propositions without induction.’ Harvey quoted this passage in his published writings, as a statement of his personal philosophic faith. He also cited in print Aristotle’s famous suggestion that: ‘If one day things become sufficiently known, then will the evidence of the senses be more worthy to be believed than reason. Reason, indeed is only to be believed when those things which are demonstrable in argument agree with those things which are perceived by the senses.’

Harvey’s ‘general’ had advocated a continual interchange between individual facts and general theories, observation and reason, particular instances and universals, as the basis of true natural philosophy. An Aristotelian had no interest in facts divorced from a broader philosophic context – to establish the dimensions or weight of an object by quantitative experiments, for instance, was meaningless in itself.

Harvey’s most famous experiment was his measurement of the quantity of the blood leaving the heart at the moment of contraction. In testing this, it has often been suggested that he proceeded along Baconian lines. After close observation, he devised the hypothesis that blood leaves the heart, in systole, in a considerable quantity. The next step was to establish how much blood was ejected with every contraction.

Yet Harvey was not interested in the exact amount of the blood ejected by the heart as an isolated fact – the fact was, in itself, of little use to him. What he wanted to demonstrate was that a great deal of blood left the heart, in order to illustrate just how forceful the systole was, and to suggest that more blood was ejected than could either be accommodated comfortably by the arteries or produced by the liver.

Accordingly, Harvey made an extremely rough estimate of the amount of blood leaving the contracting heart, based on the volume of blood contained in the left ventricle. Had he wanted to be more exact, he could have measured the amount of blood spurting out of a perforated aorta (and then multiplied it by the number of heartbeats per minute). In his lifetime, other anatomists would devise the means to make this very measurement, but even when their procedure was well known, Harvey did not adopt it to arrive at a more accurate figure. He neglected to carry out this test because exactitude was not his aim; what he required was a convincing illustration for his theory, as it were, for rhetorical effect. Neither Bacon, nor Galileo, who performed precise quantitative experiments, would have proceeded in this fashion.

There were, as a matter of fact, fundamental philosophical differences between Harvey and Galileo. Harvey always denied the Italian’s crucial distinction between the primary qualities of an external body, which could be quantified, and its secondary qualities, which could not. When Harvey came to make ‘ocular inspection’ of an animal or human body, he was as interested in its secondary as he was in its primary qualities, citing both as equally weighty ‘evidence’ for his theories. It may be worth remarking here on Harvey’s apparent lack of interest in attending any of Galileo’s lectures during his stay at Padua; he seems never to have sought out the professor of mathematics or to have troubled himself about the Italian’s ideas.

Unlike Bacon (and to a much greater extent than Galileo) theory invariably informed and preceded observation for Harvey, the universal truth coming before the individual fact. Aristotle’s deductive principles, rather than empirical data, were the starting point for his enquiries. In his investigations into the movement of animal muscles, for example, Harvey began with the following Aristotelian first principles: ‘Nature is the principle of motion and change’; ‘Nature in the making of muscles is concerned with two things, their actions and functions’; ‘Nature does nothing that can be done by fewer’, and ‘The soul working within the body is the basis and pattern for all movement’. He then proceeded to examine how these principles were embodied in particular animals.

Aristotelian first principles were also present in his mind throughout his investigations into the heart. When Harvey observed ‘the symetrie, and magnitude of the ventricles of the heart and of the vessels which go into it’, and especially the ‘carefull artifice’ of the valves, he reflected that, ‘since nature does nothing in vain’, and since ‘so provident a cause as nature’ could not have ‘plac’d so many valves without design’, the vessels and the valves must have a purpose – which, ultimately, had to be the circulation of the blood. Harvey was expressing the Aristotelian belief that the organs of the body were all designed with an end in mind, and that nature had an aim or ‘final cause’ bestowed upon it by God – a truth that Bacon’s philosophy denied.

Harvey claimed that his theory had been ‘confirmed by many ocular demonstrations’ and ‘illuminated by reasons and arguments’. It was this Aristotelian interplay between data and ideas, between magnificent generalizations and particulars, that prompted Harvey’s theory. Facts, to adapt his own metaphor, were the labyrinth; ideas and Aristotelian principles, his Ariadne’s thread.

Bacon’s writings were greatly admired by the courtiers and scholars of England. In both private conversation and in print Harvey complimented Bacon for ‘for his wit and style’, his prose being among the very finest. Yet, much to the chagrin of those modern commentators who depict the pair as intellectual allies, Harvey ‘would not’, according to a friend, ‘allow [Bacon] to be a great philosopher’. ‘He writes Philosophy’, Harvey would say in a tone of derision, ‘like a Lord Chancellor – I have cured him.’ As the Lord Chancellor presided over the legal courts, Harvey may have been implying that Bacon wrote like a barrister, who regards truth as something to be proven by factual evidence rather than philosophical ingenuity, and who is motivated by the goal of practical social utility, instead of that of attaining true knowledge.

In quipping that he had ‘cured’ his patient, Harvey could have been alluding to an intellectual joust between the pair at which Bacon was worsted, or perhaps the phrase expresses the doctor’s belief that his life’s work offered a philosophical riposte to Bacon’s manifestos of empiricism and his attacks on Aristotle. ‘To [think you can] go beyond Aristotle’, Bacon had written, using ‘the light of Aristotle’ is to ‘think that a borrowed light can increase the original light from which it is taken’. Harvey’s research into the heart and the blood would disprove that elegant epigram.

One thing is certain: by announcing that he had ‘cured’ Bacon, Harvey was not referring to having eradicated his lordship’s gout, which only became more ‘ambitious’ with time, changing its ‘old course’, by migrating from toe to heel.