Guy Brown - The Energy of Life:

We have been pursuing these ideas about matter, because they lie at the root of modern notions of energy. But Empedocles was far more than a creative physicist ( physis was Greek for nature), he was also an inventive biologist ( bios , Greek for life). According to Empedocles, the body’s flesh and blood consisted of equal proportions of all four elements, and these attracted similar elements from the environment. Thus, the same four elements constituted non-living and living matter, mind and the immortal gods. The blood circulated from the heart to the surface of the body, where air was taken in through the pores, and back again, alternately expelling and drawing in air. The motion of blood in and around the heart created thought, and so the heart was seen as the organ of consciousness. But Empedocles had a very concrete view of consciousness, seeing for example, thought as simply blood in motion. Perception occurred by elements in the blood meeting and mingling with the same elements in the environment. An external object was perceived by some elements from it entering the body and meeting the corresponding elements in the body, and their meeting or mingling was perception. Nutrition occurred through direct assimilation, that is, the elements of the body attracted similar elements in the environment to them, and these new elements fitted in place to form the growing body.

The theory of the four elements was astonishingly popular and long-lived, lasting from the fifth century BC until the chemical revolution of the seventeenth century. Yet it is hard to see quite why thinkers stopped at only four elements. Aristotle suggested a fifth – the ether – to compose all extraterrestrial things. The Chinese used five elements also (or phases): water, earth, fire, metal and wood. In modern science we have about 100 different chemical ‘elements’, which can combine to give an infinite number of possible molecules. But at the beginning of the twentieth century the Cambridge physicists J. J. Thomson, Ernest Rutherford, and James Chadwick discovered that these chemical elements were not in fact elements in the classical sense (fundamental and indestructible particles of matter), because they were destructible and composed of three simpler, indestructible particles – the proton, electron, and neutron. And these three particles were later found to interact via a fourth (short-lived) particle – the photon. Therefore, Empedocles’ four elements and two forces theory is, in outline, not that dissimilar to much more modern theories of the Universe.

Hippocrates (c. 460–377 BC) is called the founding father of medicine, and his theories of disease, cure and physiology influenced medicine and biology up until the eighteenth century. However, his own life is so mythologized that it is impossible to distinguish the basic events of his life, or even whether he really ever existed. According to legend, Hippocrates was a physician from Cos, and he practised medicine in Thrace, Thessaly and Macedonia, before returning to Cos to found a school of medicine. This school flourished from the late fifth century to the early fourth century BC, producing a vast number of highly original medical texts. Copies of around seventy of these books survive. These were conventionally attributed to Hippocrates, although he probably wrote none of them himself. The defining characteristic of Hippocratic medicine was its rejection of religious and philosophical explanations of disease, and its search for an empirical and rational basis for treatment.

Since prehistoric times, disease had been thought caused largely by gods, evil spirits, or black magic. A cure could thus be effected by ejecting the sin, spirit, or magic from the sufferer via various processes of purification. In Greece, traditional medicine was practised by priest-physicians in temples dedicated to the god Asclepius. In these temples of health, disease was apparently diagnosed partly on the basis of dreams and divination, and partly on the symptoms. Cures were half rituals and spells, and half based on fasting, food, drugs and exercise. According to later legend, Hippocrates was descended from the god Asclepius and brought up on Cos as son of a renowned priest-physician. The relationship between secular medicine (represented by Hippocrates) and religious medicine (based on faith healing or magic) in ancient Greece is difficult to discern, although apparently not as antagonistic as today.

Hippocrates and his followers accepted the doctrine of the four elements as an explanation for the natural world, but their concern as doctors was with disease’s causes and treatment. The four elements – earth, fire, air, and water – cannot be seen in anything approaching a pure form in or on the body. Also they knew relatively little about the inside of the body, because dissection was prohibited on both religious and ethical grounds. So the Hippocratics concerned themselves with what they could see and use in the diagnosis of disease, particularly the bodily fluids: blood, saliva, phlegm, sweat, pus, vomit, sperm, faeces and urine. Gradually the doctrine evolved that there were only four basic fluids (humours): blood, phlegm, yellow bile, and black bile. Blood can appear in cuts, menstrual flow, vomit, urine or stools. Phlegm is the viscous fluid in the mouth (saliva) and respiratory passages and comes out through the mouth and nose in coughs and colds. Yellow bile is the ordinary bile secreted by the liver into the gut to aid digestion; it is a yellow-brown fluid that colours faeces. The identity of black bile is not entirely clear, perhaps originally referring to dark blood clots, resulting from internal bleeding, which may appear in vomit, urine or faeces. However, the four humours did not only refer to these particular fluids, but were thought to be the body’s basic constituents. Health was thought to be due to the balance of these humours, and ill health an imbalance of the humours. Epilepsy was, for example, thought to be caused by an excess of phlegm in the brain blocking the flow of pneuma (vital spirits) to the brain. Thus treatment sought to restore the balance between the humours by removing the humour that was present in excess, for example by bloodletting, purging, laxatives, sweating, vomiting, diet or exercise.

The four humours (blood, phlegm, yellow bile, and black bile) were associated with the four elements (air, water, fire and earth), the four primary qualities (hot, cold, dry and wet), the four winds, and the four seasons. A predominance of one humour or the other gave rise to four psychological types. Thus, the ‘sanguine’ type, resulting from a dominance of blood, was cheerful and confident. ‘Phlegmatic’ types (with too much phlegm) were calm and unemotional. ‘Choleric’ or ‘bilious’ people (with too much yellow bile) were excitable and easily angered. ‘Melancholic’ types (too much black bile) were, obviously, melancholy, that is sad or depressed, with low levels of energy. This was the earliest psychological classification of character or temperament, and was used to categorize different people right up until modern times. No obviously superior way of classifying temperament has, in fact, yet been devised. The theory of the four humours dominated medical thinking until about three hundred years ago. Many patients were still being bled even in the nineteenth century.

The Hippocratics and Greeks generally believed in positive health – health could be improved much further than the absence of illness towards well-being. Modern medicine is mainly concerned with negative health (i.e. illness), and how to restore us to health, rather than with helping us feel ‘on top of the world’. The Hippocratics were much concerned with regimen or lifestyle, both in health and disease, mainly involving the correct balance of food and exercise. The importance of exercise to both physical and mental health was recognized, and was institutionalized in gymnasia where exercise was practised on a social basis. If you had gone to Hippocrates in 400 BC (assuming you could find him) complaining of lack of energy he might have given you a detailed regimen involving an exercise programme, with a warning about too much or the wrong type of exercise; a diet, particularly including strained broths; a lot of hot and/or cold baths, and massages; some sex (if lucky); and some obscure advice about the relations between your energy and the wind direction, season of the year, etc. This would have been, in general, a reasonably effective regimen, and you would be lucky to get better advice today from your doctor.