Phase changes, or the transformation of quantity into quality and vice versa
Reason in Revolt sets out to explain the laws of dialectics using modern scientific examples. In the section, Quantity and Quality, Woods discusses the dialectical concept of the transformation of quantity into quality, which is exemplified, as we shall see, by the way heated water changes into steam. This is an important concept both for Marxists and also for scientists, who use the term ‘phase change’ or ‘phase transition’ for changes such as the transition from a liquid to a gaseous state.
In modern philosophy, the concept was first fully developed by Hegel, who took it from the ancient Greeks.
Hegel used the example of water changing from a liquid to a gas in his Science of Logic and elsewhere. He showed how a constant addition of a quantity of heat to water leads to a ‘qualitative leap’ at boiling point. Water above boiling point no longer has the ‘quality’ of being a liquid. Instead, it is a gas, a qualitatively different form of matter.
Criticising the maxim, ‘Nature does not make leaps’, Hegel wrote:
“Again, water when its temperature is altered, does not merely get more or less hot but passes through from the liquid into either the solid or gaseous states; these states do not appear gradually; on the contrary, each new state appears as a leap, suddenly interrupting and checking the gradual succession of temperature changes at these points.”
Science of Logic, p369
Additional quantities of heat at boiling point do not lead (under normal circumstances) to a further increase in the temperature of the water, it leads to a qualitative change – water turns from a liquid into a gas. The same applies if the temperature of water is reduced:
“Water, in cooling, does not gradually harden as if it thickened like
porridge, gradually solidifying until it reaches the consistency of ice; it
suddenly solidifies, all at once. It can remain quite fluid even at freezing
point if it is standing undisturbed, and then a slight shock will bring it
into the solid state.”
Science of Logic, p370
Hegel’s observations are scientifically accurate. Physicists call this type of change, when water changes from a liquid phase to a gaseous phase, a phase change. The fact that nature makes leaps from one form to another, such as from a liquid to a gas, is seen as an important concept in physics and cosmology today. Brian Greene explains how cosmologists today examine periods in the distant past when the rapidly expanding early cosmos itself underwent phase changes (speculation about a period of “inflation” in the early universe is thought to undergo phase changes). Greene himself uses the example of water changing into a gas. The concept of phase changes or transitions, Greene comments, “helped scientists make definite predictions that have been experimentally proved”. (The Fabric of the Cosmos, p268)
This process of change is represented in materialist dialectics in the expression, “the transformation of quantity into quality and vice versa”. The addition of “vice versa” indicates that the reverse is true: a change of quality brings new characteristics which can be quantitatively measured. For instance, the qualitative change of water from a liquid to a gas brings about a gas with a certain pressure and temperature which can be quantified.
In discussing the maxim, ‘Nature does not make leaps’, Hegel was also seeking a justification for leaps that take place in society – revolutions. Hegel is well aware that the French Revolution of 1789 was described as “unnatural” by detractors such as Edmund Burke, the ‘father of Conservatism’. Burke argued that unless change is gradual it will end in disaster because nature does not make leaps.
Woods also attempts some scientific observations while giving the same example of the phase changes of water. But unlike Hegel and Engels, his scientific knowledge is lacking. For instance, he states:
“Until it reaches boiling point, the water keeps its volume. It remains water, because of the attraction of the molecules to one another.”
Reason in Revolt, p49
But water does not “keep its volume” and neither Hegel nor Engels suggest that it does. If a liquid is heated it expands and its volume increases: this is how a thermometer works. Further, it “remains water” even when it turns to a gas (water vapour or steam). And it does not remain liquid because of the “attraction of the molecules to one another” but because of atmospheric pressure. Lower the atmospheric pressure sufficiently and the water will boil without any addition of heat.
Woods then states that the volume between the atoms increases in water which is heated which, of course, must mean an increase of the volume of the water as a whole. He then attempts to describe boiling at the molecular level. He writes:
“However, the steady change in temperature has the effect of increasing
the motion of the molecules. The volume between the atoms is gradually
increased, to the point where the force of attraction is insufficient to
hold the molecules together.”
Reason in Revolt, p49
But Woods has confused melting with boiling. In Dialectics of Nature, Engels discusses phase changes at the molecular level in great detail, but makes no such scientific errors (relative to his epoch, of course).
Melting takes place during the heating of a solid, such as ice, when the molecules become too energetic and the bonds between them break. This is what Woods’ description resembles. In this way ice turns into water, which flows with little restriction from molecular bonds. Boiling essentially takes place when, during heating, evaporating molecules become more and more numerous until, at a certain point, these molecules escaping from the surface of the water counteract the pressure of the air molecules on the surface of the water. At this point the water boils. It is quite a different process. This is standard science which can be found in any textbook.
In Dialectics of Nature, Engels quotes Hegel on the phase change of water, and then goes on to give a very significant example:
“Similarly, a definite minimum current strength is required to cause the
platinum wire of an electric incandescent lamp to glow; every metal has
its temperature of incandescence…”
Dialectics of Nature, p87
This particular type of leap in nature, the points at which metals glow at various specific stages of heating, (e.g. red hot, white hot, etc) was vexing the minds of the scientists of the time. They were looking for an equation which showed how gradual processes could lead to these sudden changes in colour, or different energy states. But none seemed to work. When, at the turn of the 20th century, Max Planck found a formula which satisfied experimental observation, the formula contained discrete leaps from one energy level to another. Planck termed the discrete packets of energy, suggested by his formula, “quanta”.
Had they been alive to witness it, Marx and Engels would have derived no small satisfaction at Planck’s discovery, not least because Hegel, discussing leaps in nature, quite coincidentally even used the same term. Any existing thing, Hegel wrote, “is essentially a relation of quanta”. This quanta may undergo “quantitative alteration”, Hegel continues, within a range in which it “does not change its quality”. But, “there enters a point in this quantitative alteration at which the quality is changed and the quantum shows itself … so that the altered quantitative relation is converted into … a new quality, a new something.” (Science of Logic, p367) Planck’s quanta marked the beginning of quantum mechanics, which takes for its basis that physical systems (such as atoms) leap from one discrete energy state to another.
Electrons and protons
In another discussion of dialectics in the section, The Unity and Interpenetration of Opposites, Woods aptly uses the atom as an example of how opposites interact with each other.
In an atom, electrons swarm round a nucleus composed of protons and neutrons. But the electrons carry the opposite charge to the protons, and in this way, among many others, all physical things made of atoms are comprised of, or are “interpenetrated” by, opposites. Woods quotes Richard Feynman, the US physicist, who said “All things, even ourselves, are made of fine-grained, enormously strongly reacting plus and minus parts, all neatly balanced out.” (Feynman quoted in Reason in Revolt, p64)
The opposite charges are united in the atom. In capitalist society, the ‘opposites’ of the exploiting boss and exploited worker are also bound together and mutually dependent in the production process. Opposing classes are united (in a geographical sense) in each capitalist county. They are a unity of opposing forces in this sense. But these opposing forces will lead, under the right conditions, to an explosion.
After reading Hegel’s Science of Logic, Lenin regarded this concept of a unity of opposites as central to dialectics. Lenin quotes Hegel, who said that the understanding of “opposites in their unity” is “the most important aspect of dialectic”. (Science of Logic, p56) We will discuss the origins of this concept in ancient Greece shortly, where it can be traced to the Ionian philosophy of ‘coming into being’ and ‘passing away’, and we will meet it again when we discuss the nature of modern science.
But Woods’ science is weak. Pointing out that the electron has a negative charge and the proton a positive charge, Woods begins by asking:
“Why do the contradictory forces of electrons and protons not cancel each
other out? Why do atoms not merely fly apart? The current explanation
refers to the “strong force” which holds atoms together.” (p64)
But the contradictory ‘forces’ of electrons and protons do cancel each other out, in the sense that the atom becomes neutrally charged if it has the same number of electrons and protons.
The striking thing is not that electrons and protons do not ‘cancel each other out’ but that they do. The proton has 1836 times the mass of the electron, but exactly the same size charge, only positive rather than negative. The question ‘why do atoms not fly apart’ seems like an odd question to ask also. After all, the positive and negative charges of the electron and proton attract each other. And what puzzled scientists, before the development of the science of quantum mechanics, was why the electron did not spiral into the atom’s nucleus. The strong force, incidentally, does not hold the electrons and protons together as Woods appears, perhaps unintentionally, to state (elsewhere he gets this right), the electrical force does.
Woods gives a number of examples of opposites, but then concludes with a rather sweeping statement:
“There are two kinds of matter, which can be called positive and
negative. Like kinds repel and unlike attracts.” (p65)
This curious statement (two kinds of matter?) is reminiscent of the outlook of the German idealist philosopher Friedrich Schelling at the turn of the 19th Century. Schelling used the example of the north and south poles of the magnet as a metaphor for the world and its contents, to suggest that change in nature expresses itself through a duality of polar opposites, a philosophy that was very influential for a period. In this way, Schelling, for a period a close friend of Hegel, contributed to the development of the dialectic of the interpenetration of opposites, which Hegel developed further.
But Woods’ statement reduces the complexity of the universe and its contents to a very crude formulation. What of gravity, of the neutron, of quarks and neutrinos and those sub-atomic particles which appear to come in sets of threes in various ways? The dialectic of the interpenetration of opposites is a tool which in various ways can undoubtedly aid the comprehension of nature and society, but it is reduced to an absurdity in such sweeping pseudo-scientific statements which can lead to objections or even ridicule from the scientifically minded.
The first passage on modern science in Reason in Revolt comes at the beginning of the section, Everything Flows. Woods claims:
“Particles are constantly changing into their opposite, so that it is
impossible even to assert their identity at any given moment. Neutrons
change into protons, and protons into neutrons in a ceaseless exchange
of identity.” (p45)
There is no truth in this. A neutron that has escaped from an atomic nucleus will decay after about twelve minutes into three particles: a proton, an electron and a neutrino, but this process is quite different to the “ceaseless exchange” pictured here. Later, Woods says that the famous German physicist Werner Heisenberg’s exchange force “implied” this supposed “ceaseless exchange” of identity between protons and neutrons. (p96) It does not. The exchange force deals with exchanges between identical particles, not different ones, which would lead to a violation of the law of conservation of charge. It is a well-understood phenomenon.
Although dialectics certainly suggests that science will find a time limit beyond which protons will decay in some way, and teams of scientists are testing to find that limit – nevertheless the proton is stable over very long periods. A twelve-year experiment, started in 1989, suggested that the proton has a lifetime of at least ten million billion billion billion years (1034 years – a one with 34 zeros after it). It does not ceaselessly change, as Woods asserts.
Woods’ aim is to suggest that nature is not immutable but that change penetrates down to the most fundamental particles. In many ways this is true, if one avoids sweeping statements. But what Woods applies to the smallest particles he will not apply on the largest scale. Engels showed that in the Newtonian conception of the universe, “nature was obviously in
constant motion, but this motion appeared as an incessant repetition of the same processes”, and thus nature was seen as essentially immutable. Kant, says Engels, changed all that. (Anti-Dühring, p73) Yet, surely, when Woods concludes his discussion of cosmology and modern physics he retreats to the point of view of this same “incessant repetition of the same processes”. He writes: “All individuals must perish, but the wonderful diversity of the material universe in all its myriad manifestations is eternal and indestructible. Life arises, passes away, and arises again and again. Thus it has been. Thus it will ever be.” (p225)