And you, ye stars! * * * * You too once lived— You too moved joyfully Among august companions In an older world, peopled by Gods, In a mightier order, The radiant, rejoicing, intelligent Sons of Heaven! But now you kindle Your lonely, cold shining lights, Unwilling lingerers In the heavenly wilderness, For a younger, ignoble world. And renew by necessity, Night after night your courses, * * * * * * * Above a race you know not, Uncaring and undelighted[33].
Of the origin of energy we have not solved the riddle, we have given it up; but instead of coming from without we know that it comes from within. As Mr Benn puts it, we have extended the atomistic method from “matter” to motion. Harvey’s contemporary, Francis Bacon, sagaciously guessed that heat is an expansive motion of particles; but he regarded heat and cold as two contrary principles. Almost in the same generation the brilliant John Mayow perceived a substance in the air “allied to saltpetre,” which passed in and out of the blood by the way of the lungs or placenta. “Innate heat” then gave way to phlogiston; but it was not till the discovery of oxygen and of the conservation of energy that we attained a theory of energy, and finally got rid of “matter and form,” and of all the thicket of metaphysics, relating thereto; through which in the day of Harvey no mind, however mighty, could have made its way.
In the history of medieval thought we must always bear in mind that in neither of its two periods were theology, logic, metaphysics, psychology, or even physics, fully differentiated; and before the Arabian literature they were not differentiated at all[34]. Logic, which for us is but a drill, and, like all drills, a little out of fashion, was for the Middle Ages a means of discovery, nay, the very source of truth; thus every man carried his own busy laboratory within him. The heirs of Porphyry and Boetius had no other method in their possession. The dialectically irresistible was the true (κατάληψις); thus was man to succeed “irrefutabile aperire secretum.” To begin to think before beginning to learn is a hollow business, yet then logic furnished the theorems which experience might illustrate at its leisure; and nature was contemplated under philosophy. The differentiation of psychology began with the translation of the De anima[35], and the recognition of the relation of the percipient; hence, in the second period, Roger Bacon denounced the pretensions of logic, and John Duns, that brilliant backslider, forced them to an absurdity. Again, on the translation of the Metaphysics, theology parted into the studies of the doctrines of God and the soul, which belong to theology proper, and of being, in modes, kinds and universals, which belong to metaphysics. Medicine again was a confusion of spheres, as was theology; the care of the soul and the care of the body were the ends of knowledge, and their means contained all knowledge. Thus when we hear that Alcuin ordered the formal teaching of medicine, it was under the name of “Physica”; and not until the Physics of Aristotle came to light did the various branches of natural history become in their turn not only definite studies but also self-sufficient, aside from the art of healing. To this day the healer keeps the name of “physician”; and the subject at Cambridge the name of Physic. It is well to be reminded that although the soldiers of truth must be separated into several regiments, nevertheless for its edification the healing art must draw, directly or indirectly, on all natural science. Robert of Lincoln, Albert of Cologne, and all the Masters of that time studied medicine—that is τὰ φυσικά—as a solid part of knowledge, which in their apprehension was not only a whole but also a manageable whole. Even Francis Bacon did not realise fully the littleness of man in the presence of nature; he hoped that for his harvest man would on a right method—by, let us say, a reformed astrology and a reformed alchemyquickly surprise the secret of her processes: thus Bacon was the last of the Summists. With the differentiation of the several spheres of knowledge, and the perception of the vastness and variety of each, man has ceased to hold not the unity but the simplicity of nature; and he has given up summaries: the theologian rules no longer in metaphysics and psychology; the physician is no longer the only naturalist.
Systems succeed each other but give each other the hand; it takes many a generation to kill a strong theory outright: realism, shaken by Roscellinus and Abélard, and scotched by Hales and Ockham, survived to mislead Harvey; and still it stretches its withered hand over us in the nursery, in the school, and in the great arguments of life[36]. Malebranche warned us against our deceptive terminology. “Ils prétendent expliquer, (he says), la nature par leurs idées générales et abstraites, comme si la nature était abstraite.” The methods of the English grammar schools are even now medieval in so far as their teaching begins, as it mostly does still, with abstract propositions.
Mysticism gathered over Germany; in Paris to this day nature is constrained in the artifices of logic and rhetoric; and to this day platonism, chiefly by the influence of the Florentine humanists and perhaps of the Cambridge school of Henry More, has moulded both thought and language in England. John Hunter conceived a “materia vitæ diffusa”; and but yesterday Huxley had to say of Owen’s theory of “spermatic force” that an artillerist might as well attribute the propulsion of a bullet to “trigger force.” We profess Aristotle, and we talk Plato. Even by men of science it is daily forgotten that the only being is the particular. After the Faith then, realism—the belief in principles and kinds having external existence, and in formative essences to be reached by abstract thinking—stood another adversary against natural knowledge.
But, stronger even than realism, was a third adversity—the pride of the human mind. Socrates, although, for ethics and politics, he initiated the inductive method, was disposed to regard physical speculations as but a rational pastime[37], and the political and ethical study of man as the only serious engagement of thought. Aristotle took up natural knowledge as an encyclopedist[38]; he rarely verified his facts and he made no experimental researches[39]. The medieval church held that “ex puris naturalibus cognoscere” was a meagre and might be a mischievous amusement; and it sought to confine speculations to final causes, that is to the animation of the world by an intelligent Being, as man animates his own instruments: though, as Roger Bacon declared, final causes must have physical means. Even Locke thought nature to be hopelessly complex, and urged that ethics is the proper study of man. The asceticism derived from the East, disdainful of carnal things, brought the dualism of matter and spirit into monstrous eminence; and, in respect of medicine, in a few generations it turned the cleanest people in the world into the most filthy[40]. Moreover, are we not bound to admit that, as ultimate analysis was dangerous to the synthesis of the Faith, so for unwieldy and unstable societies in which ethical and political habits had not yet become engrained, to descend from transcendental explanations to explanations by lower categories was fraught with some danger to lofty and imposing standards of custom and conduct? Nature is too base, says St Anselm, for us to argue from it to God; we must argue from God to things. Analysis is a disintegrating function; the departure of the scientific enquirer is rather from below upwards: it is not only his bias but also his deliberate method to decline to use the discipline and the conceptions of higher categories until he is satisfied that those of the lower are inadequate. A certain natural process may not be attributed to those of chemistry until those of physics are proved to be inadequate; to another process biological conceptions and methods are denied until those of physics first, and then of chemistry, have been tried and found wanting; psychological conceptions are denied to another until in their turns the physical, the chemical, and the physiological are exhausted[41]; and so on: and within each category the same economy prevails. Now this scientific economy, perhaps first formulated, or effectively used, by William Ockham, in the phrase “entia non sunt multiplicanda”—known as “Ockham’s rasor”—is what is called now-a-days “materialism”; and there is no doubt that the method, legitimate, nay, imperative, as it is in natural science, may in custom and conduct engender a personal and collective habit of apprehending in lower categories, and even of contentment in them until strong reason be shown to go higher[42]. A higher order of ideas is put in a lower order of language; the “ὁδος εἰς τὸ κάτω” of Heraclitus. The danger of this attitude lies in loss of effort, of aspiration, and even of imagination; he must stoop on the weary oar who, knowing no anchorage, is ever stemming the drift. Notwithstanding is there in history any lesson sadder than this, that where ideals have been loftiest sin and failure have most abounded? a lesson from which Carlyle learned that “the ideal has always to grow in the real, and often to seek out its bed and board there in a very sorry way.”
Almost to this day then the mechanical arts, presumably concerned rather with the lower categories, have been regarded as base; and the craft even of the laboratory as unworthy of great souls. Anatomy had to labour against antipathy both ecclesiastical and popular; chemistry and mechanics were gross pursuits, unless endowed with the perilous distinctions of alchemy and sorcery. Unfortunately this charge upon the dignity of man was made heavier rather than lighter by Petrarch, and by the later humanists of the Renascence; even in the 17th century we find in Oxford that Boyle was bantered by his friends as one “given up to base and mechanical pursuits.” As Boyle himself put it in his delightful way—“There are many Learned Men ... who are apt to repine when they see any Person capable of succeeding in the Study of solid Philosophy, addicting himself to an Art (Chemistry) they judge so much below a Philosopher, and so unserviceable to him. Nay, there are some that are troubled when they see a Man acquainted with other Learning countenance by his example sooty Empiricks” ... “whose Experiments may indeed be useful to Apothecaries, and perhaps to Physicians, but are useless to a Philosopher that aims at curing no Disease but that of Ignorance.”[43]
Lord Herbert of Cherbury, who early in the seventeenth century attended lectures at Padua, opined that natural science deals with “ignoble studies, not proportioned to the dignity of our Souls.” In the eighteenth century indeed, grave English physicians, humanists who forgot how Aristotle had exclaimed that marvellousness lies in all natural phenomena, scorned the trivial curiosity of John Hunter respecting flies and tadpoles.
It is part of my argument to-day to point out one evil of many which this prejudice has wrought for medicine. The progress of an applied science dependent as it is upon accessions of advantage from other arts, yet on the whole is from the simple to the complex; from facts of more direct observation to those of longer inference: and this path was the more necessary when the right method of inference—the so-called inductive method—had not been formulated, and indeed was barely in use. Now in medicine, from Homer to Lord Lister, direct observation and the simpler means of experiment have obtained their first-fruits on the surface of the body. In Homeric times surgery was the institution of medicine, and kings concerned themselves with the practice of it. From Erasistratus to Celsus physicians of all schools practised medicine and surgery as one art. Galen urges the unity of medicine, and Littré points out that this unity is maintained in the Hippocratic writings. In the Middle Ages the ascetic contempt for the body—partly Stoic, chiefly oriental,—the barren alliance of medicine with philosophy, and the low esteem of mechanical callings hid from the physician the very gates of the city into which he would enter. Francis Bacon says of the physicians of Harvey’s day, that they saw things from afar off, as if from a high tower; and, again, that after the manner of spiders they spun webs of sophistical speculation from their own bowels. Surgery, by virtue of its imperative methods, was kept clear of philosophy on the one hand and of humanism on the other; and in Paris the establishment of the Collège de St Côme, afterwards the Academy of Surgery, protected the higher surgery against the rabble of barbers. Upon the raft of anatomy and surgery, with some clinical aid from Salerno, positive medicine crossed the gulf between Byzantine compilations, monkish leechcraft, Arab starcraft and alchemy, and the scientific era of Harvey[44]. But physicians were not only blind to the great services to the whole art of medicine of the surgical school of Lanfranc in the fourteenth century, of Guy de Chauliac in the fifteenth, and of Paré and Gale in the sixteenth century, advances even accelerated in the seventeenth, but they ignored also their very origin, and even withdrew from fellowship with the surgeon; to our grievous harm from those days unto our own[45]. Surgery was excluded from the Faculty of Medicine of the University of Paris; and from the Royal College of Physicians of England, which was, and is still, enabled by charter to teach surgery, and to grant licenses therein. Fabricius, the master of Harvey, was fortunately as great a surgeon as anatomist, and such was Fallopius. In this College Harvey lectured on anatomy and surgery, and he left his surgical instruments to us; for us Caldwal founded a lectureship in surgery which has been allowed virtually to lapse. From the progress of anatomy which, under the protection of the Italian nobles as formerly of the Alexandrian, went hand in hand with surgery, physicians drew then little advantage; and so in part perhaps it came about that although Vesalius, Fallopius, and Fabricius broke up the traditional anatomy of Mundinus, yet anatomy did more even for the fine arts than for physiology; and medicine at the end of the Middle Ages had not recovered the standard of Alexandria. Against this adversity also had to contend the founder of physiology whom to-day we celebrate.