In some respects I am ill equipped for my office; of the history of the practice of Medicine from the time of Galen to the time of Harvey I am almost ignorant, I fear wilfully ignorant. Well indeed may we turn our eyes away from those centuries wherein one of the chief callings of man fell into unexampled and even odious degradation; yet I trust that in me this ignorance and this aversion may be compensated by some familiarity with the history of thought in the Middle Ages, a familiarity acquired during thirty-six years of abiding interest, and occasional study.
The discovery of the circulation of the blood by William Harvey is commonly regarded among scientific discoveries as pre-eminent if not unique. I can quote but two opinions on this matter, both taken beyond our own land. In France, Dr Daremberg exclaims “Voici Harvey! Comme au jour de la création le chaos se débrouille, la lumière se sépare des ténèbres!” In Germany, Dr Baas says that Harvey stands alone in respect of the world of life; that his discovery of the inner working of the microcosm takes a place equal to, if not indeed higher than, those of Copernicus, Kepler and Newton in respect of the macrocosm. It will be my endeavour to show that these judgments are historically justifiable.
To put the discovery of the systemic circulation of the blood in its true light, we must have some notion of the history of philosophy, science and medicine. Medicine, and herein it is in contrast with Theology and Law, had its sources almost wholly in the Greeks. Not only in the doctrine of the four elements of Empedocles, a doctrine which has survived almost to our own day[2], and in the physical theories of Heraclitus and Leucippus, did medicine, for good or ill, first find a scheme of thought, but in the schools of Hippocrates and of Alexandria it was based also, and far more soundly, upon natural history and anatomy. The noble figure of Galen, the first experimental physiologist and the last of the great Greek physicians, portrayed for us by Dr Payne in the Harveian Oration of 1896, stood eminent upon the brow of the abyss when, as if by some convulsion of nature, medicine was overwhelmed for fifteen centuries. To the philosophy of medicine, Galen had given more than enough; to its natural history he had contributed in the following of Hippocrates; to its discoveries he had given the greatest of all means of research, individual genius; to its methods he had given, but in vain, that indispensable method, practised first perhaps in history by Archimedes and the Alexandrians, of verification by experiment; a method, after Galen, virtually lost till the time of Gilbert, of Galileo and of Harvey.
In the growth of human societies small civilisations, however exquisite, have been sacrificed to the formation of vaster and vaster congregations of men; thus only, it would seem, is an equilibrium to be reached of sufficient stability for the highest ends of mankind. Greece, beautiful as was her bloom, penetrating as was her spirit, perhaps because of her very freedom of thought, never became a nation; her city states were too wilful to combine. The Macedonian power broadened the foundation of polity eastward and westward; and this work was carried as far perhaps as sword and fasces could carry it by the power of Rome. But even the Roman peace, bought as it was at the cost of learning and the arts, was but a mechanical peace; in the wilder, more turbulent and more heterogeneous peoples of the later Empire the bodies but not the wills of men were in subjugation. The great system of Roman Law, which Numa, the Moses of Rome, had invested with supernatural awe, had become but an external rule; even in Rome herself, poorer in people, poorer in commerce, poorer than ever in ideas, the sanction of patriotism was failing, and her citizens were held together for the most part by their baser and more dangerous passions[3]. For Eastern Europe the University of Constantinople established a compact and uniform system of thought, subtle prolix and acquisitive rather than original or profound; but in the West, under the Frank and later Northern devastations, the very traditions of learning and obedience were broken up; schools were closed, and even the art of writing was almost lost. Then it was that the cohesion and development of Western Europe were saved by a new and a wonderful thing. From the East, the home of religions, had spread, like an exhalation, Christianity, that religion which proves by its survival that it is the fittest sanction for the will of man. This religion, entering as a new spirit into the ancient fabric of Roman Empire, was to hold men’s service in heart and soul as well as in body; yet to this end no mere mystic or personal religion could suffice: clothing itself with the political and ritual pride and even with the mythology of the pagan Empire it inspired a new adoration; but it imposed also upon Europe a catholic and elaborated creed. To preserve the authority of the common faith not only must every knee be bowed, not only must every heart be touched, but to build and to repair its fabric every mind must also bring its service. How the scheme of the Faith was built up, how oriental ecstasy and hellenistic subtlety, possessing themselves of the machinery of Roman pomp, were wrought to this end, we may briefly consider.
As, politically, under Diocletian and Constantine the ancient world gave place to the new, so in the third century philosophy was born again in neo-platonism[4], the offspring of the coition of East and West in Alexandria, where all religions and all philosophies met together. The world and the flesh were crucified that by the spirit, man might enter into God[5]. Pure in its ethical mood, neo-platonism, says Harnack, led surely to intellectual bankruptcy; the irruption of the barbarians was not altogether the cause of the eclipse of natural knowledge: to transcendental intuition the wisdom of the world had become foolishness. Yet even then, as again and again, came the genius of Aristotle to save the human mind. The death of Hypatia was the death of the School of Alexandria, but in Athens neo-platonism survived and grew. Proclus, ascetic as he was, was versed also in Aristotle; and he compelled the Eastern mysteries into categories: so that on the closure of the School of Athens by Justinian (a.d. 529) a formal philosophy was bequeathed to the Faith; the first scholastic period was fashioned, and the objects and methods of enquiry were determined for thirty generations. From Aristotle Europe adopted logic first, and then metaphysics, yet both in method and in purpose Origen and Augustine were platonists; rationalised dogma lived upon dialectic, and conflicted with mysticism; but logic, dogma and mysticism alike disdained experience.
Thus, no mere external sanction, stood the Faith; threefold: from the past it brought its pompous ritual, it appealed by its subtle dogmatic scheme to the intellects, and by its devotion to the hearts of men. Through the mirage of it, when its substance had waned, Copernicus, Galileo, and Harvey had to steer by the compass of the experimental method. This was their chief adversity, and of other adversities I have to speak.
The visitor to the Dominican Church of St Catherine at Pisa will see on its walls St Thomas of Aquino with the Holy Scriptures in his hand; prostrate beneath him is Averroes with his Great Commentary, but beside him Plato bearing the Timæus. It was the fortune of the Faith that, of all the treatises of Plato, the Timæus, the most fantastic and the least scientific, should have been set apart to instruct the medieval world; that the cosmical scheme of the Timæus, apparelled in the Latin of Chalcidius,—for there were then no Greek texts in the libraries of the West,—should for some 500 years have occupied that theoretical activity which Aristotle regarded as the highest good of man[6]. Again, those works of. Aristotle which might have made for natural knowledge fell out of men’s hands[7], while in them, as Abélard tells us of himself, lay the Categories, the Interpretation, and the Introduction of Porphyry to the Categories, all in the Latin of Boetius[8]; treatises which made for peripatetic nominalism, but whereby men were versed rather in logic and rhetoric than in natural science. Thus Plato’s chimera of the human microcosm, a reflection of his theory of the macrocosm, stood beside the Faith as the second great adversary of physiology.
The influence of authority, by which Europe was to be welded together, governed all human ideas. As in theology was the authority of the Faith, so in the science and medicine of the first period of the Middle Ages was that of the neo-platonic doctrines, and, in the second period, of the Arabian versions of Galen and of Aristotle; furthermore in this rigid discipline metallic doctrine almost necessarily overbore life and freedom. It is not easy for us to realise a time when intellectual progress—which involves the successive abandonment of provisional syntheses—was unconceived; when truths were regarded as stationary; when reasons were not tested but counted and balanced; when even the later Averroists found final answers either in Aristotle or in Galen[9]. Thus in the irony of things it came to pass that Harvey was withstood by the dogma of Galen who, in his own day, had passionately appealed from dogma to nature.
Porphyry of Tyre, who lived in the 3rd century, may be called the founder of both Arabian and Christian scholastics. He was an Alexandrian, but of peripatetic rather than platonic opinions. In the Isagoge, or Introduction to the Categories, already mentioned as translated by Boetius about 500 a.d., he set forth plainly a problem which during the Middle Ages rent Western Europe asunder; a problem which, says John of Salisbury[10], engaged more of the time and passions of men than for the house of Cæsar to conquer and govern the world; one indeed which even in our day and country is not wholly resolved.
The controversy lay between the Realists[11] and the Nominalists; and the issues of it, in the eleventh century,—at which time the “Dark Ages” passed into the earlier of the two periods of the Middle Ages,—were formulated on the realist side by William of Champeaux, while the Breton Rousselin, or Roscellinus, had the perilous honour of defining them on behalf of the nominalists[12]. To see the depth of the difference we must step back a little, to a time when metaphysics and psychology were not distinguished from other spheres of science[13], and all research had for its object the nature of being. Plato himself held ideas not as mere abstractions but in some degree as creative powers; and we shall see how potent this function became in the thought of the Middle Ages when, in the ardour of research into the nature of being, the modes of individuating principles were distinguished or contrasted with an ingenuity incomprehensible to Plato or Aristotle, or at any rate undesired by these greater thinkers. Aristotle avoided the question whether form or matter individuate; he held that there is no form and no matter extrinsic to the individual. But by the medieval realist every particular, every thing, was regarded as after some fashion the product of universal matter and individual form. Now “form” might be regarded, and severally was regarded, as a shaping, determinative force or principle, pattern type or mould, having real existence apart from stuff, or, on the other hand, as an abstract principle or pattern having no existence but as a conception of the mind of the observer. The realists roundly asserted that form is as actual as matter, and that things arise by their participation—without whiteness no white thing, without humanity no man; and not individuals only: for the realist, out-platonising Plato, genera and species also had their forms, either pre-existent (“universalia ante rem”), or continuously evolved in the several acts of creation (“universalia in re”). Indeed for the extreme realist every “predicamental modality” was “aliquid ens separatum”; for instance, the soul, the active intellect, the passive intellect, and so on: conversely, by fusing idea with will, for other philosophers realism would get pushed back into efficient reason or divine will, and almost vanish[14]. By this latter route the Sorbonne, originally opposed to the Thomists, became nominalist after all; as did those once pious realists the Augustinians and Cistercians. Setting aside then the extreme nominalists, who would have dissolved thought by declaring all creatures to be so individual as to be incomparable,—“pulverising existence into detached particulars,” as some one has put it—and that names of kinds are mere nouns, or indeed mere air (“flatus vocis”), the prevalent nominalists were content to deny to ideas, forms, principles, or abstractions any other existence than as functions of the human mind—as subjective conceptions. For Ockham, says Hauréau, an idea was but a modality of the thinking subject. Abstractions then for these thinkers were but mental machinery for analysis of the concrete. Aristotle was as obscure and inconsistent in his language herein, and often elsewhere, as he was profound and scrupulous; but when his works came to be studied as a whole, and in the original tongue, the influence of his method, rather than the close consistency of his language, told against realism: virtually he was a conceptualist, and he found reality, where Plato denied it, in the particular object of sense[15].