Kitabı oku: «The Energy of Life:», sayfa 2

Our caveman has now got some theories, but it does not seem to be doing his cavewoman any good. She has gone cold. The caveman now needs to add one more item to his list of differences between living and dead: body heat. The body temperature of living mammals and birds is normally higher than their surroundings, cooling to that of their environment at death. If our body temperature is lowered by more than a few degrees, if for example we fall into freezing water, then we rapidly die. Clearly heat has an important connection to life. In pre-industrial times, the only significant producers of heat were animals, fire and the sun. Aristotle, for example, thought of the life-force partly as a kind of fire inside the body. And the association between heat (and movement) and the life-force, may well explain the widespread belief that the sun was a god, and the use of fire in religious rituals. In fact there are a number of other important similarities between life and fire: both are produced by the burning of organic matter (fuel/food) with air (supplied by a bellows or breathing), which generates heat, movement, and residual waste (ash/faeces). This analogy was important both in ancient Greece and in much more modern times. For it was the key concept in the development of the modern scientific idea of body energy, although the theory could not be used productively until chemical concepts of burning were developed by Lavoisier in the eighteenth century.

Back with our caveman, things are looking bleak. The cavewoman’s body has started to decay. First the flesh rots away, leaving the skeleton, then the bones themselves disintegrate to dust. Although the process is slow, its effect is dramatic: we start with a highly organized human body and end with a pile of dust, which merges into the soil. There is obviously little hope of reversing this process, and nowhere for the soul to hide afterwards. This is clearly the great disaster of the human condition. Many cultures have expended immense efforts trying to either prevent or circumvent this problem. The ancient Egyptians were the most zealous, utilizing mummification, pyramids, tombs, sacred objects, temples, an extensive priesthood, literature and mythology to evoke a whole parallel world beyond death. In Egypt, bodies were at first buried in dry sand in which they could survive for up to a thousand years, but were shrivelled and dried out. Subsequent use of stone coffins resulted in the flesh disappearing – supposedly eaten by the stone. This is the origin of the Greek word sarcophagus (meaning ‘flesh eating’) perhaps reflecting a prehistoric notion that the body and soul of the dead could enter into and be preserved in stone. The bodies were, in fact, eaten by micro-organisms too small to be seen. The Egyptians developed mummification to prevent this process, although of course lacking any knowledge of the existence of bacteria. Mummification was, however, never entirely successful, and the final resort of both the Egyptians and later cultures was to circumvent the problem by favouring the idea that the mind or soul could separate from the body at death, and either live independently (in heaven or another world), or in other objects (such as in statues), or another body (reincarnation).

The decay of the flesh leaves the bones. Some cultures believed that the bones represented the essential core of the human, the flesh its disposable clothing. The bones contained a vital fluid, which we would now identify as the marrow encased by major bones, the spinal cord encased by the spine, the brain encased by the skull, and the cerebro-spinal fluid permeating the cavities of the brain and spine. All these ‘bones’ surround, as if protecting, a greyish-white gelatinous material or fluid, which in ancient Greece was thought to be the origin of semen, another off-white gelatinous fluid. Thus, semen was thought to be derived from this vital gel, a kind of creative force, constituting the brain, spinal cord and bone marrow. The Romans consequently believed that men’s tiredness after orgasm and ejaculation was due to the draining of creative force throughout the body. The myth that masturbation causes blindness may originate from this ancient concept that the sperm partly derives from the brain. In Greek legend, gods and goddesses were born directly from Zeus’s head (Athena) or thighbone (Dionysus), because this is where the creative force was thought to be located. The belief that bones were the essential core of the human being, encasing an individual’s procreative powers, may have motivated the preservation of the bones of ancestors in many cultures.

The body’s decay after death appears the counterpart of its growth in life. The growth of the body is dependent on food, and it is all too evident that when a human stops eating, they stop growing, shrink, then die. Clearly there was something in food or in eating that was related to life, and this link was all the stronger because food consisted of recently dead animals or plants. Food could thus be thought of as containing either a soul or soul-nourishment. In most early cultures, there were religious rites involving human or animal sacrifice and the eating of the flesh. Often the food was blessed or otherwise transformed so that a god or soul might enter and be absorbed into the body of the eater. The Christian mass is partly derived from earlier Greek Orphic and Bacchic rituals, where food was magically transmuted into the body and soul of a god, which then entered into the body and soul of the person eating. A version of this is described in Euripides’s Bacchae, where the normally well-behaved, upper-class ladies of Athens achieve an ecstatic state, hunting a wild animal representing the god Dionysus, tearing it limb from limb and devouring the raw flesh. This was a means of obtaining ‘enthusiasm’, which in Greek means the entry of a god into the person. Thus, enthusiasm is a kind of mind energy, and these rituals were a means of obtaining it.

The idea that food was incorporated into the body – that when eaten, the substance of the food became the substance of the body – predates Classical Greece, but just how this transformation might occur was not elaborated until the Greeks devised various schemes. One idea was that food was broken down and transformed into blood, then congealing (as in blood clotting) in various ways to produce the body’s organs. While this might explain the growth of children, it did not really explain the fact that although adults do not grow, they require large amounts of food. Later the idea of ‘dynamic permanence’ was developed by Alcmaeon in the sixth century BC, according to which the structure of the body was continuously breaking down and being replaced by new structures and substances derived from food. This would account for the fact that the body slowly decayed after death, when no food could be eaten. The general concept that material things consist of smaller components, which can be rearranged to give all the different forms or structures of things (such as food or the body), was an extremely important and fruitful one. It was particularly developed by Greek philosophers, such as Plato and Democritus, leading to much speculation as to what the simple components might be, for example water, fire, air or earth or atoms of different shapes.

During illness and starvation, the fat of the body shrinks, while in times of health and plenty, it expands. Until comparatively recently, fat was often associated with health and riches. Some Andean Indians still associate the fat with the spirit, and thus when a man ‘fades away’ in chronic illness or starvation, his spirit fades away too, often thought to have been stolen by a sorcerer. Fat, blood and air are the basic body fluids in traditional Andean physiology, and fat is the energy principle distributed from the heart via a system of channels and rivers mirroring the hydraulics of the Andes. This imaginative physiology is indeed partly based on an analogy of the body with the mountains and rivers, so that the head is like the mountain peaks lost in the clouds, while the legs are the river valleys. Illnesses associated with particular parts of the body can be treated by offerings of coca, blood and fat at earth shrines located at appropriate parts of the mountains. In the modern West, where food is plentiful and wasting illness rare, being fat now has the connotation of being unhealthy and poor. But, of course, only a couple of hundred years ago a rotund outline was celebrated, and the skinny figure, favoured today, was feared and pitied.

Our caveman is now distraught. He has watched his mate die: first she stopped moving, then she stopped breathing, her heart and pulse stopped, then the heat left her body, which then started to decay leaving bones and then dust. Watching this process, he has formulated new ideas about life, but these are completely useless in actually dealing with death. Many thousands of years later, we are in the same position: although we know much more about death, we are completely incapable of reversing it. However, let us return to our caveman, who is now in a reflective mood. Many of the differences between the living and the dead are visible and obvious, but perhaps the most important difference is neither visible nor obvious: what happens to the mind? What happens to our perception, thoughts, feelings and will at death? Thoughts, feelings and perceptions are not visible in other people, even if we open up their bodies, and there is no obvious machinery for producing them inside the body. The caveman could not see his mate’s thoughts and feelings when she was alive, so it is conceivable that when dead she is still capable of producing them, although they remain invisible to him. Perhaps the mind or soul enters the body at birth and leaves it at death. Accordingly, the mind of the caveman’s mate may still be alive though her body is dead and gone. This thought may not provide the caveman with much immediate relief, but implies that when he himself dies his mind may survive in some form, and may even enable him to meet up with his mate again.

Different cultures had quite different ideas about whether and in what way the mind might separate from the body at death. But the ancient Egyptians, Indians and Greeks, believed that the mind could survive death. This belief has obvious repercussions on how we view the relations between mind, body and matter generally. If the mind can separate from the body at death and survive as an invisible but active entity, then we could conclude that life consists of two separate entities: an invisible active mind (or soul) which occupies a passive material body. Furthermore, all other entities in the world might also consist of a similar combination of mind and matter. This dualistic distinction between active mind (or spirit) and passive matter foreshadows that between energy and matter, which replaced it: the modern concept of energy has its ancestors among the spirits.

Early explanations of the world attributed intentions or desires to objects, and interpreted events in terms of the desires of spirits and gods. This type of explanation (known as ‘teleological’ or ‘intentional’) mirrors that which we use to explain other people’s behaviour. Thus, if someone hits me over the head with a baseball bat, I might explain this behaviour by attributing it to the attacker’s anger or his intention to rob me. Similarly, if a stone fell on our caveman’s head he may have seen this as the anger or intentions of a spirit, god or even the stone itself. Nowadays, we would look for a ‘mechanistic’ explanation of such an event (for example the stone fell from a building), rather than ascribing evil intentions to the stone or the event itself. In the ancient world, there could be relatively few genuine ‘accidents’ because most events were thought intended by someone, something or some god. Thus almost everything was seen as meaningful; in complete contrast, today most physical events (such as atoms colliding or the Universe exploding) are thought intrinsically meaningless and accidental, except where human intentions are involved. And even where humans are involved, scientists often prefer mechanistic explanations. For example, the scientist may trace that blow to the head with a baseball bat to the effects of the attacker’s upbringing on his brain biochemistry, rather than a premeditated intention to rob me.

Modern science is based on mechanistic rather than teleological explanations, making a strong distinction between passive matter and the invisible mind. And the advance of science has caused a gradual retreat of intention (and mind) from the world: first from non-living matter, then from the body to the brain, and, more recently, attempts have been made by both philosophers and neuroscientists to banish it from the brain itself. Yet as individuals we prefer intentional or anthropomorphic explanations of the world, rather than cold mechanistical explanations. We prefer to think that people and animals do things because they want to, rather than because their brains make them do these things. We like to see the world and Universe as having meaning, rather than being meaningless accidents. Part of the reason science alienates people is its rejection of intentional explanation; and perhaps in turn much of the appeal of religion and literature could be their generous use of anthropomorphism and intentional explanation. You may notice as you read this book that the parts that describe the behaviour of molecules and cells in terms of their intentions, wants or needs, are more readable than the strictly scientific parts cast in terms of cold mechanism. And, moreover, there may well be a good mechanistic explanation of why we prefer intentional explanation, which is that it is hard-wired into our brains. Recent psychological research indicates we develop the ability to attribute intentions to others at the age of three, and children who fail to develop this ability (perhaps because of brain defects) are much more likely to become autistic and unable to interact functionally. Thus, our preference for intentional explanations of other people and the world is because that’s how our brains work, presumably because such explanation has been successful in promoting survival during evolution. However, during science’s evolution, it has been found that intentional explanation is relatively unsuccessful in predicting the behaviour of the world in comparison to mechanistic explanation.

The relevance of intentionality to energy is that the concept of energy has evolved partly to replace intentional explanation. Energy has replaced gods, spirits and inanimate forces as the source of all motion and change in the Universe. But fundamental theories and concepts (such as mind or energy) are not labels that can be attached to the world without distorting it, but are rather like a pair of coloured spectacles through which we can see and interpret the world. If we are short-sighted, it may be impossible to see the world at all without some spectacles (or some theory). Or the spectacles may be locked on (as happened to Dorothy and her companions in The Wizard of Oz), or imprinted in our brains, so it is well-nigh impossible to see without them. The concept of energy is one basic idea through which we now perceive the world. And we have already seen how the origin of the concept of energy is rooted in even more basic ideas about life, movement and mind. In the following chapter we follow these ideas’ evolution into our current conception of energy.

Chapter 2 THE STORY OF LIVING ENERGY

The modern concept of energy originated in the nineteenth century, a child of the industrial revolution, but its origins extend back to ancient Greece, amongst the elements, humours and spirits of the classical world. We will follow the evolution of these ideas of energy and life up to the present, as it is extremely difficult to understand the current concept of ‘living energy’ without seeing where these ideas came from.

THE ELEMENTS, HUMOURS AND SPIRITS OF THE CLASSICAL WORLD

Science started in ancient and Classical Greece, and it is there that we can begin to pick up the trail leading to our current ideas of energy and life. The Greeks were astonishingly creative thinkers. Indeed it is almost impossible to characterize clearly what the Greeks thought about anything, because they thought so many different things about any one thing, most of them mutually contradictory. (Much like the White Queen in Through the Looking-Glass, who could believe six impossible things before breakfast, without spoiling her appetite.) Indeed the Greeks were spectacularly wrong about many things. And this in itself is important because for almost two thousand years after the fall of Athens, Greece’s intellectual heirs in the Hellenic, Roman and Islamic worlds, and in Medieval and Renaissance Europe believed that whatever the Greeks thought was the unquestionable truth. The thoughts of the wise men of Greece on philosophy, science and medicine were held in the same awe and reverence as those of Moses, Jesus and Mohammed on religion and ethics. Now we know that many of the ‘truths’ discovered by the Greeks are ‘false’, but the forms of their ideas, the type of questions they asked, and the ways they went about answering them, have had a fundamental influence on the development of modern knowledge and ideas. Were it not for this relatively small number of thinkers in ancient and classical Greece, science, philosophy and western culture as we know them would not now exist.

Empedocles (c. 490–c. 435 BC) was one of the greatest all-rounders of all time, exemplifying the enormous diversity and creativity of ancient Greek thinkers. Born to an aristocratic family in the city-state of Acragas, Sicily, he assisted in a coup against the oligarchy ruling the city and was offered the crown. He refused, establishing instead a democracy, and becoming himself a politician. But, in his spare time, he also managed to be one of the greatest poets, scientists, philosophers, and doctors of his age. As if this were not enough, after banishment and exile from his home state, he became a prophet and god. Legend has it that he could work miracles, control the winds, restore the dead to life, and killed himself by jumping into the volcanic crater of Etna to prove his divinity. Whether this leap did in fact prove this or not, history does not say, though apparently all that remained of Empedocles physically were his sandals. However, his thoughts remained to haunt the intellectual landscape for over two thousand years.

Empedocles devised the theory of the four elements, described as the most successful scientific theory ever, in terms of popularity and longevity, although it was not, of course, correct. It held that everything in the world consisted of a combination of only four elements. This theory appears to be a diplomatic compromise between earlier contradictory ideas that the world consisted solely of water (Thales), an unknown and unknowable substance (Anaximander), air (Anaximenes), or fire (Heraclitus). Empedocles suggested that there was not a single fundamental substance at all, but rather four elements (or ‘roots’ as he called them): earth, fire, air and water. The advantage of having four elements rather than one, was that it was obvious to anyone that the world consisted of an incredible diversity of things, and it was hard to explain this diversity if everything consisted of the same single substance. It was also difficult to explain how anything could change, if everything was, in essence, the same. Empedocles suggested that each different type of thing in the world consisted of different proportions of the four elements, and further that change was due to exchange of some of its constituent elements. For example, he said that bone was composed of fire, water and earth in the proportions 2:1:1 and flesh was composed of all the elements in equal proportions.

However, change could not just be left to the elements. After all, why should objects alter if there was only inert substance in the world? Why should rocks fall? Why should volcanoes explode? Why should thunder and lightning wrench the skies? Change was a big problem for the Greeks. It is also intimately related to energy, as energy can be thought of as the hidden source and cause of change. How were the Greeks to explain it without invoking gods or souls or minds? How could matter alone cause change? How could something new appear from nothing? Empedocles proposed that, in addition to the four elements, there were also two forces, which he called ‘love’ and ‘hate’. Hate (or ‘strife’) pushed things apart, while love pulled them together again; and when the two forces were balanced there was no change, a standoff. This sounds like a plot for a romantic novel, but Empedocles partly conceived of love and hate similarly to the modern conception of a force, as an inanimate pushing or pulling between matter. Thus, Empedocles’ overall conception of the world as consisting of different immutable elements, pushed and pulled by forces, so that change is due to chance and necessity rather than purpose, is strikingly similar to that of nineteenth-century physics. This similarity is no accident, of course, since the modern concept is partly derived from Empedocles.

Empedocles’ view of the world does, however, diverge radically from the modern in many ways: he also saw the two forces, love and hate, in a religious sense, as a struggle between good and evil (with the four elements each identified with a different god). His scheme of things also differs from ours in that his elements correspond more to the modern phases of matter (solid, liquid, gas, and plasma) rather than to modern elements (such as hydrogen, oxygen, nitrogen, and carbon). This difference partly arises from the fact that Empedocles appears to have rejected the idea of empty space – the void or vacuum – a space where there was nothing, no elements or anything else. Since he had shown that air was a substance, he saw no reason to believe in empty space between the elements. Thus he conceived of the elements as homogenous substances, which blended together when mixed, like different-coloured paints.

Earlier thinkers (such as Anaximenes) and later thinkers (such as Democritus) took the more modern view that a substance consists of a vast number of small particles separated by empty space, and conversion from liquid to gas is not due to a change of elements, but rather to the elements moving much further apart. Thus, ice consists of water molecules held rigidly together, while liquid water consists of the same water molecules flowing over each other, and steam, or completely evaporated water, consists of the same water molecules very far apart. The Atomists – Leucippus and Democritus (c. 460–370 BC) – pushed this view of the world to its most materialistic extreme, by taking Empedocles’ world, ridding it of its religious components, but adding the void. Thus, their view was that there was nothing in the world except a vast number of tiny particles (atoms) moving through empty space. Each of the four elements had a different shaped particle, and this shape determined the properties of the element. This explanation of the world had great advantages over the no-void view, because it could explain easily how the elements could mix and then separate: particles simply passed between each other; whereas this was hard to explain if there was no empty space between elements. Similarly, Empedocles had considerable difficulty explaining why the millions of things in the world had such startlingly different properties, if only differing in the proportions of the four elements. Why should a difference in proportions cause new properties? Democritus (and modern science) could explain this by the arrangement of the atoms within the object. New properties arose from new spatial arrangements or configurations of the atoms. There were an infinite number of ways of arranging atoms of four elements, and consequently an infinite number of possible things or materials. This is the essential secret of the success of modern chemistry and biology: explaining the properties of things in terms of the microstructure of the elements of which they consist. Unfortunately for the Atomists, the technological means did not exist in Greece to probe the microstructure of things, and thus test their theories.

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.