In Search of a Theory of Everything

by Demetris Nicolaides

  * * *

  1Aristotle, Physics 239b9–14, trans. Daniel Kolac and Garrett Thomson, The Longman Standard History of Philosophy (New York: Pearson, 2005), 33.

  2Elias, Commentary on Aristotle’s Categories 109.20–22. Or see Richard D. McKirahan, Philosophy Before Socrates (Indianapolis: Hackett, 2010), 182 (Kindle ed.).

  3Bertrand Russell, The History of Western Philosophy (New York: Simon & Schuster, 1945), 124.

  4Aristotle, Physics 239b14–20, trans. Demetris Nicolaides. Or see Daniel W. Graham, The Texts of Early Greek Philosophy: The Complete Fragments and Selected Testimonies of the Major Presocratics (Cambridge: Cambridge University Press, 2010), 261 (text 18).

  5Ibid., 239b30–33. Or see Graham, Texts of Early Greek Philosophy, 261 (text 19); ibid., 239b5–9. Or see Graham, Texts of Early Greek Philosophy, 261 (text 20); Diogenes Laërtius 9.72. Or see Graham, Texts of Early Greek Philosophy, 261 (text 21).

  6David J. Furley, Two Studies in the Greek Atomists (Princeton, NJ: Princeton University Press, 1967), 119.

  7Robert J. Oppenheimer, Science and the Common Understanding (New York: Simon & Schuster, 1954), 40.

  8Aristotle, Physics 209a23–25, trans. Demetris Nicolaides. Or see Graham, Texts of Early Greek Philosophy, 263 (text 24).

  9Simplicius, Physics 140.34–141.8. Or see Graham, Texts of Early Greek Philosophy, 255 (text 7); ibid., 140.27–34. Or see Graham, Texts of Early Greek Philosophy, p. 259 (text 13).

  10

  The Chemistry of Love and Strife

  Introduction

  Empedocles (ca. 495–ca. 435 bce) managed to reconcile the antinomies between the Heraclitean becoming (the constant change) and the Parmenidean Being (the constancy) by introducing four unchangeable primary substances of matter: earth, water, air, and fire, later called elements, and two types of forces, love and strife. Change was produced when the opposite action of the forces mixed and separated the unchangeable elements in many different ways, an idea in basic agreement with modern chemistry or, more fundamentally, with the standard model of particle physics. Moreover, the cosmological cycles, described in his unique cosmology, could have addressed successfully the deceptively simple question, Why is the sky dark at night?, before the cosmology of the big bang had it figured out in the twentieth century.

  Elements and Forces

  Unlike Thales, who taught that the primary material can transform and change its nature (for example, water can become ice), Empedocles held (as did Anaximenes) that the nature of a primary material must always remain the same, like the Parmenidean Being. But with a single primary material of unchangeable nature, he could not account for the observed material diversity of the world. Thus, he postulated four such materials, the elements, which were uncreated and imperishable—neither born out of nothing nor perishable into nothing. His choice for these elements was wise because with them he could explain the three phases of matter: the element earth could account for the solid phase, water for the liquid, air for the gaseous. Furthermore, through fire he could account for light. Now, not only do the elements not change into one another; they do not change at all. But that did not matter. Because Empedocles explained nature’s enormous diversity by imagining love (the force) mixing the elements with one another and strife (the other force) separating them from each other, in infinitely numerous proportions and combinations, forming composite objects or dismantling them. For example, love can mix earth and water to produce mud, but strife can separate the earth and water from mud. Hence, love causes attraction of unlike elements (thus, in a sense, per Aristotle, indirectly it also causes repulsion of things that are alike). And strife causes repulsion of unlike elements (thus, in a sense, indirectly it also causes attraction of those that are alike).

  Empedocles explained the unique properties of objects in terms of the proportions of the elements they contain. A hot object, for example, contained more fire than a cold object. And a wet object contained more water than a dry one. Thus, the quantitative difference of the various materials present in an object determines the qualitative difference between objects.

  Birth and growth occur while the elements mix, as in a blooming flower, and decay and death occur while the elements separate, as in a shriveling flower. Coming to be (the birth, the generation of something) occurs simply from a mixture of things (the elements) that already exist, not from Not-Being (nothingness)—that is, there is no absolute birth. And perishing (the death of something) occurs simply from a separation into things that also already exist, not into Not-Being—that is, there is no absolute death. That there isn’t absolute birth or absolute death is, of course, part of the Parmenidean thesis and is also accepted by Anaxagoras and Democritus.

  Like the elements, the forces were corporeal, uncreated, unchangeable, and imperishable. But it was their motion through the elements that caused the elements to move, too—either pushing them together to mix or pulling them apart to separate. Hence, forces were the source of motion and consequently of change.

  Force, in natural philosophy, appears for the first with Empedocles, who interprets nature in terms of matter and forces. Matter and force, however, became popular with Newton’s work: first, with his three laws of motion, and second, with his law of the universal force of gravity. According to his second law of motion, for example, the cause of motion is a force: you pull an object and the object moves. Also matter can produce a force: the sun produces gravity, or an electron the electric force. Nonetheless, while the matter-force interpretation of nature is still immensely practical, it began fading away in twentieth-century physics: forces, in modern physics, gradually became no longer essential. This is a topic to be revisited in chapter 12. Force, in particular, an action-at-a-distance type (as is Newton’s force of gravity), we will see, remarkably, was never required in the atomic theory of Democritus.

  Empedocles and the Standard Model

  Empedocles’s idea of forces mixing and separating a fixed number of primary materials is in fundamental agreement with the standard model of particle physics. Whereas Empedocles proposed two forces and four primary elements (renamed “particles” by Lederman),1 the standard model considers three fundamental forces—the electromagnetic, the nuclear weak, and nuclear strong (recall gravity is not part of the standard model). It also considers twelve types of particles of matter—the six quarks and six leptons (or actually more by more detailed considerations). Of course, unlike Empedocles’s elements, in modern physics, quarks and leptons are changeable; they transform to energy or from one material particle into another, although again, these transformations occur by obeying conservation laws, and so in essence something is still unchangeable (e.g., the total electric charge is the same before and after a transformation). Still quarks and leptons are brought together by the forces in a multitude of combinations and proportions to form atomic nuclei, atoms, molecules, flowers, and in general all the plethora of small and large objects, animate and inanimate, similar and dissimilar; but the forces can also break down larger objects into smaller ones.

  In Empedocles’s chemistry every object is made by a unique mixing proportion of the elements—for example, a bone, he says, is two parts earth, two parts water, and four parts fire (though the sources do not explain how he derived that). (His Pythagorean influence2 is evident in his use of numerical ratios in mixing processes, just as the Pythagoreans used ratios to describe music, the motion of heavenly bodies, even in their failed attempt to find a ratio for the √2.) Analogously, in modern chemistry every chemical compound is made by a fixed proportion of the chemical atoms—for example, a water molecule, H2O, is always made of two atoms of hydrogen and one of oxygen. Of course, modern chemistry can be analyzed even more fundamentally within the context of the quarks and leptons of particle physics and still preserve Empedocles’s notion of fixed proportions. That is, H2O, for example, is really a fixed mixture of two protons (one from each hydrogen nucleus) plus eight more protons as well as eight neutrons (from the oxygen nucleus) plus two el
ectrons (one from each hydrogen) plus eight more electrons (from the oxygen). Now, electrons belong in the lepton family of particles and, thus, they are fundamental (they are not made of other types of particles), but protons and neutrons are not fundamental: a proton is made from three quarks, two up and one down (“up” and “down” are quark names); a neutron is made from one up and two down quarks. In addition, quarks and leptons are kept together or pushed apart via the continual exchange of force particles, the photons and gluons, in our example. Analogously, in Empedocles’s theory the fixed proportions of the elements are achieved via the constant competition of love and strife.

  Empedocles was interested not only in the composition and changes of individual objects but also of the world as a whole.

  The Cycles of the World

  The structure of the cosmos is spherical for Empedocles, and the changes in it occur without an ultimate purpose or divine intervention (the latter is also the view of the atomists). Instead, nature is ruled by chance and necessity (by potentiality and actuality, in Aristotelian philosophy): namely, only some outcomes are possible, but which ones actually occur is completely the result of chance. Interestingly, this is the meaning of probability in quantum mechanics.3 For example, only some energies are possible for the hydrogen atom, but the energy (the necessity, or actuality) which is actually observed at any one time is completely the result of chance—the probability of each potentiality is calculated from the wave functions.

  Nature in the cosmology of Empedocles has always existed (thus, it has an infinite past time), for, like Parmenides, he believes ex nihilo nihil fit (nothing comes from nothing, in Latin). Thus, nature has no beginning or end. It goes through everlasting cycles of growth and decay, gradually and continuously, through four basic periods.4 In the first period of the cycle, love dominates totally but temporarily, mixing the elements completely. In the second period, strife begins its influence, and so there is a gradual transition to partial mixing and separating. In the third period, strife dominates totally but also temporarily, separating the elements from each other completely, so each, in its pure form, occupies a different region of space: one region of the universe is occupied only by earth, another only by water, another only by air, and the last one only by fire. In the fourth period, love makes its gradual comeback, and so again there is a partial mixing and separating of the elements. Life (the evolution of plants and animals) and nature in general as we know it (with the sun, planets, stars) are happening during the second and fourth periods. The state of our cosmos is temporary for Empedocles, and it is gradually being succeeded by another.

  Now, for a universe with no beginning or end, with “first” and “last” to have no absolute meaning, why should one thing (or concept) be more primary (fundamental) than another? “Again, if everything is created from four things [earth, water, air, fire, or quarks and leptons] and resolved into them, why should we say that these are the elements [the primary, the fundamental entities] of things [of the composite objects or of the emergent properties] rather than the reverse—that other things [the composite objects] are the elements [primary, fundamental entities] of these? For one gives birth to another continually, and they interchange their colors and their entire natures [properties] throughout the whole of time.”5 With this Epicurean reasoning in mind, nature might be a two-way street, nonhierarchical: subtle sameness, which we are in search of to construct a theory of everything, might be as significant and fundamental of a concept as its opposite, perceptible diversity. Generally, reductionism—understanding (constructing) the universe from the bottom up (microscopically to macroscopically)—might just be as valid a philosophy as its opposite, emergentism, understanding (deconstructing) the universe from the top down.

  Interestingly, if we are not myopic in our comparisons, these four periods have several similarities with modern cosmological models of the universe.

  Cycles in Modern Cosmology

  According to the big bang model, initially everything was completely mixed together, space, time, matter, and energy (like Empedocles’s first period). Life as we know it was then impossible because the universe was tiny and superhot, without stars or planets, just a super-dense mixture of tiny particles. The universe has since then been evolving, reaching its astronomical size and diverse state of today, with galaxies, stars, planets, and life (as in Empedocles’s second period). Now, if, as speculated by various big bang models, the universe is “open,” it will continue to expand forever, increasing its size so much that ultimately everything in it will be completely separated (as in Empedocles’s third period). It will then be a cold, lifeless universe without planets or stars, only isolated tiny particles. But if, as also speculated by other models, the universe is “closed,” then after it goes through a third period (a state of maximum, though not necessarily complete, separation of everything in it, during which stars might fade out and die), it will stop expanding and will begin contracting, resulting again in life-bearing partial mixing and separation (as in his fourth period). The fourth period is much like the second, for as matter is brought together in a shrinking universe, the particles coalesce again to form countless light-giving stars and life-sustaining planets to orbit them. But in a “closed” universe the contraction will continue until the crushing force of gravity ultimately collapses the universe in on itself, and brings once more everything completely together (the first period all over), causing a “big crunch” (the opposite of the big bang). If the universe were to reverse and begin to close, would the second law of thermodynamics reverse, too? As is, the second law is supposed to dictate the “arrow of time,” the familiar directionality (flow) of time from past, present, future, where things (flowers, people, stars, the whole universe) all tend toward greater disorder (entropy) and basically grow old. If, in a closing universe, however, the second law were to reverse (i.e., the order, not the disorder, of things were to increase), the arrow of time would reverse, too, in which case we might feel getting younger as in the reversed cosmos of Plato’s cosmological myth.6

  We are not sure if we live in an ever-changing universe going through endless cycles of big bangs, expansions, contractions, and big crunches. Still, we could describe rather accurately the main events in the universe and when they occurred by starting from the “first” moment of the big bang until now.

  Cosmic Calendar

  In modern cosmology all events in the universe span 13.8 billion years in time. To gain a perspective of such time vastness, we often employ a cosmic calendar. It is a metaphor by which 13.8 billion years, the estimated age of the universe since the big bang, are compressed into just one calendar year—about a month per 1 billion years. The initial bang, the big bang, is supposed to have happened at precisely midnight, 00:00:00 (which, in the 24-hour time notation, is the 0th hour, 0th minute, 0th second) on January 1, causing the expansion of the universe. What caused the bang is still unknown, although it is speculated to have been a kind of repulsive gravity that is predicted from the equations of general relativity. But what is known is that this expansion has been happening ever since and up until now, the last moment of December 31 at 24:00:00, increasing the size of the universe from an unimaginably small size initially, possibly point-like, to today’s immensity, of about 93 billion light-years across. (Whether the universe is finitely or infinitely big or old, are questions that in truth have not been settled yet, if ever, because cosmology is a developing field. If we adhere to the philosophy that Being can neither come from Not-Being nor become Not-Being, then the universe has always been and will always be. Also it can be boundless without being infinite, as is the geometry of a sphere discussed in chapter 8.) Anyway, what banged (expanded, stretched)? Space-time did and still does. Within a minuscule period of time after the initial bang, possibly by a mere 10–36 second, the universe underwent an immense faster-than-light7 expansion, a big bang, an idea known as cosmic inflation. In the blink of an eye it expanded by a factor of 1030!8

  By about 14 min
utes (380,000 years) after the big bang, at 00:14:00 on January 1, the universe expanded, became less dense, and cooled significantly and as a result became transparent to light (as a clear-air day is to visible light), allowing for the first time the “afterglow” of the big bang, the oldest observable light formally known as the cosmic microwave background, to travel freely through space and time, from there and then to here and now, and to be seen today (by radio telescopes) coming from every direction in the universe—a triumphal verification of the big bang cosmological model. Earlier than the first 14 minutes, the young universe was very dense and hot and thus opaque to light—as a foggy day is to visible light—thus, light could not travel far. January 1, at 00:14:00, is also the instant that the simplest and lightest of the chemical atoms, hydrogen, first formed when a relatively cooler universe allowed electrons and protons to capture each other via the electric force.