Guy Brown - The Energy of Life:

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.

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.