Laws are Not Rules, and Vice Versa

If a physicist traveled to another planet, she would expect Newton’s laws of motion to operate there as they do here, but she would not expect to hear Finnish being spoken. If an earthly legislative body decreed that for one day each year the speed of light must be 50 percent slower, that piece of legislation would not be obeyed; light would be a scofflaw. If an asteroid struck Earth and wiped out all life, any remaining molecules of DNA would continue to behave according to their chemical and physical properties, but their ability to choreograph the complex dance of other molecules would vanish.

In this chapter we have been studying the contrast between how the physical world functions and how sequences function. Systems of sequences demonstrate unusual behaviors with respect to time and space, matter and energy. Pattee says it all boils down to what he calls the difference between laws and rules.*’ This is an important distinction, but it can be confusing at first because in everyday conversation most people use law in two different senses. We talk about the law of the land, meaning rules and regulations that are created by governments, but we also call gravity a law of nature that is fundamental to how the universe operates.

To Pattee, laws—like the laws of physics—have three characteristics. First, they are universal, which means they hold true at all places and times, even on distant planets.5' Second, they are inexorable, which means they cannot be evaded or modified, even by determined legislatures. Finally, they are incorporeal, which means they are obeyed without the need for any external mechanism. A piano falling from a crane does so without any help.

Pattee’s rules are the opposite of laws. They do not hold true at all places and times, they can be evaded or modified, and they are dependent upon external mechanisms in order to function. In other words, rules are local, arbitrary, and structure-dependent. Life and civilization are more like rules than laws, as are the behavioral mandates issued by governments. They are not found everywhere, they do not have to be exactly as they are, and they apply only if there is equipment around to execute them.

However, the molecular sequences of DNA, RNA, and protein that make life possible depend on the absolute reliability of the laws of physics. If those laws were not universal, not inexorable, or not incorporeal, then sometimes life would work and sometimes it wouldn’t. It certainly would not be life as we know it. Life is only possible because certain aspects of the physical environment, such as energy from the sun, appear and disappear on a reliable, predictable schedule.

Here’s the thing. No matter how robust and reliable the living world appears to be, it does not share the absolute properties of physical law. “A mature physicist, acquainting himself for the first time with the problems of biology,” says Nobel laureate biophysicist Max Delbriick,

is puzzled by the circumstance that there are no ‘absolute phenomena’ in biology. Everything is time bound and space bound. The animal or plant or micro-organism he is working with is but a link in an evolutionary chain of changing forms, none of which has any permanent validity.38

However regular they seem to us, the regularities of biology and culture are contingent, not necessary. They are like rules, not laws.

Our biological regularities are far from universal, having arisen on a single lonely planet among likely billions, and within a temporal window that represents one-quarter of the age of the universe. And they are hardly inexorable; the diversity of the living world is largely due to chance, to what Crick calls frozen accidents.59 As for incorporeality, as we have seen, biological regularities depend on the continuity of living matter. DNA transcription, translation, and replication cannot take place without an ensemble of helper molecules in a functioning cell, and language cannot survive without humans to speak it. So, in comparison with the universality, inexorability, and incorporeality of physical law, biological regularities are 0-for-3, none of the above.

This leads to a quandary. It is one thing to say that the sequences of the living world are reliant upon the lawful behavior of the underlying physics and chemistry. But it is quite another to say that the speech and text that govern human civilization are dependent in the same way upon the lawful behavior of the underlying biology. This is because we just saw that the living world is not lawful; it is rule-ful, time bound and space bound. In one sense, life is no more than a set of arbitrary molecular constraints foisted upon the lawful behavior of the underlying physical world.

Biology may float on a layer of physics and civilization on a layer of biology, but the complicating factor is that we know physics is lawful and biology is not. The distinction between laws and rules thus has the potential to trip us up in our effort to provide a unified account of sequences. How can we describe them as two examples of one sort of thing when one is built on the laws of physics and the other on the non-laws of biology?

The answer seems to be that, although the regularities of biology may be arbitrary and rule-like, they can rise to the stature of physical law in explaining how sequences behave. Natural selection can simulate a law, says Delbriick.60 Evolutionary change may be a necessary component of the living world, but so too are stability, reproducibility, and predictability. Evolution does not require the absolutes of physics, merely the predictable good-enoughs of natural selection.

So coherent and persistent is the living world that its contingent regularities appear lawful for all practical purposes. It is a testament to the coordinating power of DNA sequences that ecosystems operate as if biological consistency were just as lawful as gravity or electromagnetism. Many organisms depend not only on the predictability of the physical environment, like gravity and solar energy but also on the predictable presence of other organisms in that environment. Green plants may rely on the astrophysical regularities of planetary motion and nuclear fusion, but herbivores depend on a reliable supply of green plants and carnivores on a reliable supply of herbivores.

Predator-prey and parasite-host relationships come into being only because predators can bank on a supply of prey, as can parasites of hosts. As observers, we may recognize the contingent nature of these relationships, but from the perspective of natural selection the availability of food sources is as lawful as gravity. While saying so might make a physicist wince, inexorability is in the eye of the beholder. “Many of the most beautiful regularities of the natural world [are] only approximate regularities,” says Herbert Simon.61

As a result, our higher-level sequences of speech and text can rely on the biological regularities of our bodies and brains in the same way that sequences of DNA can rely on the regularities of the physical world. It’s a hierarchy; the rules of the upper level organize and coordinate the lawful behavior of the lower level; genes coordinate the underlying physics and language the underlying biology.

Speech is coupled to the biology of human bodies and brains and thus behaves more like a law. To persist across the generations, sequences of human speech require nothing more than a reliable supply of new speakers. As reproducing biological creatures, we are generally happy to maintain that supply. However, the sequences of written language are not as tightly coupled to our underlying biology. Literacy behaves more like a rule. Texts are a cultural invention not shared equally by all members of our species. To facilitate what Jack Goody calls the reproduction of the readers, we divert significant economic resources to social institutions of instruction and learning.62 We will return to this point in Chapter 7.

The distinction between laws and rules is readily seen in human institutions. “Even though social systems observations are many hierarchical levels away from the measurement of electrons,” says Pattee,

there is still the need to distinguish the dynamical 'laws’ of social organizations from the descriptive rules that we call goals, plans or policies. Here, the concept of law does not have the degree of inexorability or universality as does physical law, but relative to the goals of the individual it has similar effects. Certainly, one characteristic of social dynamics is its rate-dependence as opposed to the rate-independence of our descriptive social plans and policies.63

We will take a closer look at institutional behavior in Chapter 8.

Although the regularities of biology are not quite as reliable as the laws of physics, they are reliable and lawful enough for natural selection to take place. And in the case of humans they provide sufficient stability and reliability for the sequences of speech and writing to perform their organizational roles in society. Systems of sequences may be layered atop other pre-existing systems of sequences, like a laminate, but the lowest level is grounded in physical law.