Lecture 10: Emergence

 Foundations of Liberty
The Intellectual Crisis of the Modern World

A Lecture Series with Prof. Thomas Patrick Burke

In the last lecture we examined a remarkable new development in biology, in the field of genetics, a field which occupies the center of the stage in the neo-Darwinian theory of how evolution takes place. Previously it had been taken for granted by most scientists that traits were transmitted from one generation to the next solely by means of the genes. This meant that novelty or improvement, on which any evolution of new species must depend, could occur only through mutation, an accidental alteration in the chemistry of the gene. But the vast majority of such accidental alterations are harmful rather than beneficial to the organism, a fact that does not add greatly to the credibility of the theory.

The new development is the discovery that there is a pathway of inheritance which lies outside the genes, and is therefore termed epigenetic. This takes place chiefly through the mechanism in each living cell by which the genes are activated or “expressed.”  Through devices that affect gene expression, such as methylation, the attachment of a methyl group to the amino-acid cytosine in the DNA , the organism can respond to its environment in ways that can be passed on to its offspring. The result is similar to the inheritance of acquired characteristics earlier suggested by Lamarck but emphatically rejected by most followers of Darwin. The net effect of epigenetics is that we can now see a way in which it seems practically possible for novelty and improvement to occur as we would expect with living, teleological beings.

We turn now to another recent development in science, this time in physics, which also seems to have possible significance for the relationship between science and human values, and specifically for the view we have been advocating in these lectures, Plato’s thesis that living things move themselves, i.e, life is not mechanistic but teleological. The development in physics that we are referring to is the theory of emergence.

In earlier lectures we saw there are two main reasons why science is and must be mechanistic in its methodology.  They are first the rational principle of parsimony in explanation, otherwise known as Ockham’s Razor, which states that explanatory factors should not be multiplied without necessity, or, all things else being equal, a simpler explanation is always to be preferred to a more complex one.  As we saw, mechanistic explanations are always simpler than teleological ones.

Secondly, only mechanistic explanations can be proven, since only they allow the kind of prediction and verification that is required for genuine proof of a theory.  Teleological explanations do not have that kind of definiteness.

It has followed from these reasons that the physical sciences are reductionist.  Reductionism means explaining higher or more complex phenomena by means of lower or less complex ones, and attributing therefore more reality to the lower level than the higher one. Reductionism explains the macro level of reality, the world of our ordinary experience, by means of the micro level, the world we find in our microscopes. For example, we explain the phenomenon of color in a fabric by pointing to the behavior of the electrons in the surface of the fabric when they encounter light. The behavior of the electrons is real and can be demonstrated scientifically. By comparison, the reality of the color is secondary, a function of the electron behavior; it might almost be called an illusion caused by the electrons.  The real world as science reveals it to us is the micro world of atoms and atomic particles and the forces that act between them, rather than the world revealed to us by our ordinary experience.

In recent years, however, there has been a big change in this. It has come to be realized that there are cases where this does not work, but rather the opposite: where it is the higher and more complex level that explains the lower and simpler one. Such, for example, is the case with Newton’s laws of motion. The first of these laws is the law of inertia, that a body at rest will remain at rest, and a body in motion will remain in motion, unless it is acted upon by an outside force. These laws cannot be explained by any simpler or lower level of reality, but they can be predicted by quantum mechanics, which is more complex, as a limiting case.

More is Different

In 1972 the American physicist Philip Anderson, then working at Bell Laboratories, published in Science a short paper with the title “More Is Different.” The argument of this paper was that although reductionism is almost universally accepted among working scientists, it is not in practice very useful. The reason is that “The ability to reduce everything to simple fundamental laws does not imply the ability to start from those laws and reconstruct the universe.” “The behavior of large and complex aggregates of elementary particles, it turns out, is not to be understood in terms of a simple extrapolation of the properties of a few particles. Instead, at each level of complexity entirely new properties appear.” “At each stage entirely new laws, concepts, and generalizations are necessary, requiring inspiration and creativity to just as great a degree as the previous one.”  Although scientists assume that psychology can be reduced to biology, and biology to chemistry, and chemistry to physics, “psychology is not applied biology, nor is biology applied chemistry.”  Anderson shows why this is the case by discussing some particular molecules. The sugar molecule has 40 atoms. But there is a difference between sugar molecules produced in the bodies of living beings and those we synthesize by a chemical reaction. Those we make by a chemical reaction are, on average, symmetrical, in terms of parity between  left-handed and right-handed versions, but in those produced in living bodies, and only in them, the symmetry is “broken.”

Arguing from the macro level to the micro is often in science called analysis. Arguing in the reverse direction, from micro to macro, is termed synthesis. Anderson remarks that the relationship between a system and its parts is “intellectually a one-way street. Synthesis is expected to be all but impossible; analysis, on the other hand, may be not only possible but fruitful in all kinds of ways.” He gives the example of superconductivity, which however is too technical to reproduce here. In conclusion he remarks, “we have yet to recover from the [arrogance] of some molecular biologists, who seem determined  to try to reduce everything about the human organism to “only” chemistry, from the common cold and all mental disease to the religious instinct. Surely there are more levels of organization between human ethology and DNA than there are  between DNA and quantum electrodynamics, and each level can require a whole new conceptual structure.”  Anderson’s paper has been one of the most-discussed in the history of physics. It is usually considered to have given rise to the idea of “emergence” in physics. Anderson went on to win a Nobel prize.

Sound Quantization

Since 1972 many other examples of emergence in this technical sense have been recognized. One striking case is that of sound quantization. As everybody knows, sound consists in a wave motion through the molecules of a medium, such as the air. The molecules of the medium vibrate, each passing its vibrations on to the next.  It turns out, however, that under certain circumstances sound no longer consists of a wave, but of particles. The physicist Robert B. Laughlin, co-winner of a Nobel Prize in physics, describes it in this way:

This astonishing phenomenon (sound quantization) is the closest thing to real magic I know. Sound is familiar to everyone as the vibration of elastic matter, typically air but also solid walls, as you know if you’ve attempted to sleep with a loud party going on next door. Of the two, sound in solids is the more interesting from a quantum perspective because it continues to exist and make sense even at ultralow temperatures. Measurements at such temperatures reveal that it is particulate. Suppose, for example, a sound transducer is attached to a solid and turned on, thus beaming sound into the solid, and then reduced in intensity to make the amount of sound small. A sound receiver on the other side of the solid detects not a faint tone but sharp pulses of energy arriving at random times. This quantized transmission of pulses evolves into  the more familiar transmission of tone when the intensity is increased – an everyday example of the emergence of Newtonian reality out of quantum mechanics . . . the conclusion becomes inescapable that particules of sound exist, even though they do not exist when the solid is disassembled into atoms. The particles emerge, just as the solid itself does. Sound quantization is a particularly instructive example of particle emergence because it can be worked out exactly, in all its detail, starting from the underlying laws of quantum mechanics obeyed by atoms . . . The analysis also reveals that the particles of sound acquire more and more integrity as the corresponding  tone is lowered in pitch, and become exact in the limit of low tone. Very high-pitched sound quanta propagating through a solid can  decay probabilistically into two or more quanta of sound with a lower pitch, this decay being aptly analogous to that of a radioactive nucleus or an elementary particle such as a pion. . . . The quantum properties of sound are identical to those of light. This fact is important, for it is not at all obvious, given that sound is a collective motion of elastic matter while light ostensibly is not.  (A Different Universe, p. 106 ff.)

Implications of Emergence

If the theory of emergence is true, it constitutes a profound revolution in our way of seeing both the world and science, a revolution which seems perhaps as important as  the discovery of quantum mechanics. It implies that no particular level of reality is epistemologically privileged. The micro level is not more fundamental than the macro, nor the macro than the micro, but both are of  equal importance for understanding the universe. Many of the collective phenomena (i.e. those that emerge) are not necessarily caused by the single phenomena out of which they appear to be built, but each must be understood in the light of the other.  In other words, all levels of reality are equally real and equally significant.  Laughlin sums the situation up as follows:

What we are seeing is a transformation of worldview in which the objective of understanding nature by breaking it down into ever smaller parts is supplanted by the objective of understanding how nature organizes itself. (A Different Universe, 76).

In  other words the theory of emergence is not reductionistic. He goes on to argue that the implications of emergence theory are so far-reaching that they effectively usher in a new scientific era.

Much as I dislike the idea of ages, I think a good case can be made that science has now moved from the Age of Reductionism to an Age of Emergence. a time when the search for ultimate causes of things shifts from the behavior of parts to the behavior of the collective. (ibid., 208)

Laughlin refers to a number of scientists who believe that science has gone as far as it can and now has no future. In his view, however,

We live not at the end of discovery but at the end of Reductionism, a time in which the false ideology of human mastery of all things through microscopics is being swept away by events and reasons. This is not to say that microscopic law is wrong or has no purpose, but only that it is rendered irrelevant in many circumstances by its children and its children’s children, the higher organizational laws of the world.  (221).

Laughlin gives many other examples of emergence, or what he believes to be emergence.  In truth he extends the range of the concept and the theory well beyond what is generally accepted at the present time in the scientific community, if I am not mistaken. The fact is that emergence theory is admittedly in its infancy and is still highly controversial. The basic concepts involved in it are not entirely clear, nor even the line of demarcation between what emerges and what does not. The term “emergence” is used widely outside of the scientific context in many different senses. This has led some writers to draw a distinction between weak emergence, as when we say of someone that “he emerged from hiding and gave himself up to the police” where there is no new substance or law involved, and strong emergence, where there is a new substance or law or something of similar magnitude involved. Some such distinction is certainly needed.

If,  however, the theory of emergence proves to be well-grounded—as indeed it appears to be, at least to some extent, at the present time—then certain questions follow from it. It seems to me these are chiefly two. One concerns the nature of science, the other the nature of the world.

What is to be the fate of science in an emergent world? We have been arguing in these lectures that science must necessarily be mechanistic if it is to be successful. We have given the two main reasons for this: the rational principle of Ockham’s Razor,  and the necessity of empirical prediction and experimental verification.  It has long been assumed that to be mechanistic is also to be reductionist. But in an emergent world, science is no longer to be reductionist. Is it possible for science to be mechanistic without being reductionist?  Perhaps not science, but the scientist. I am not asking for any changes to science, which within its own sphere has been fantastically successful. What is most necessary is that the person of the scientist, as well as everbody else, should be able to recognize that there is more to life than mechanism.

My second question concerns the nature of the world. If the theory of emergence is correct, there is no single epistemologically privileged level of reality, as scientists previously assumed, but there are different levels. This ties in well with the account we have given of the phenomenon of life. For we have pointed out the immense difference between the living world and the inanimate one. And within the living world we see there are a number of levels of life, at least four by my reckoning: the archaea or most primitive, plants, animals and human beings. Just how these levels relate to one another from the viewpoint of explanation remains to be seen. I hope to discuss that in a coming lecture.