Ever since Albert Einstein and the Theory of Relativity, time has been described as the fourth dimension of the universe, on an equal footing with height, width, and depth. Research in recent years (since Einstein) has extended the understanding of this basic force to realms beyond the physical. Jeremy Campbell, a correspondent for the London STANDARD and author of the well-received GRAMMATICAL MAN (1982), explores philosophy, history, physics, biology, music, cybernetics, and psychology in an attempt to synthesize the effects of time in our lives.
In the physical world, he covers theories of time from the ancients (Plato and Aristotle), the Renaissance and the Scientific Revolution (Galileo Galilei and Isaac Newton), to the twentieth century (Einstein). In the post-Einstein world, time is not an absolute constant, integrally linked to space, as it had been under the earlier world philosophies.
Biological organisms exhibit marked time-dependent behaviors. Circadian rhythms are reflected in changes in body temperature and blood pressure, as well as levels of production of certain hormones, over roughly a twenty-four-hour period. It is these changes which wake us up in the morning and make us sleepy at night. Winston Churchill liked to take a nap after lunch and before Cabinet meetings because he was taking advantage of a “window of sleepability” which allows us to fall asleep in the afternoon. Other cycles are longer than twenty-four hours....
The computer is to chronobiology, Jeremy Campbell suggests, as the microscopes of the seventeenth century were to biology—it lets scientists see complexities and structures that were previously unsuspected, thus opening new areas of research that may have important consequences for medicine and psychiatry. The discoveries about rhythms, cycles, and time-sense assembled and explained in Winston Churchill’s Afternoon Nap: A Wide-Awake Inquiry into the Human Nature of Time also provide a fascinating commentary on human nature in the broadest sense of the term. Although much of the material is highly technical, Campbell skillfully uses analogies, metaphors, anecdotes, and narratives to make the book not only intelligible but also very interesting.
Chronobiology—a word not yet in most dictionaries—is the study of variations in biological function over time. Most people are aware, subjectively, of certain internal rhythms: cycles of body temperature that lead to a feeling of chill when staying up past bedtime, peak times for mental activity during the day, alternating periods of deep sleep and dreaming at night. Those in search of good news want both their weight and their blood pressure measured first thing in the morning, and pulse rates can differ by as much as ten beats per minute depending on time of day. As these and other physiological rhythms became increasingly evident, scientists until the 1970’s accepted the concept of a fixed body time and searched for a “master clock,” perhaps in the brain or endocrine system, which regulated physiological functions in tune with a regular period that encompassed roughly twenty-four hours but did not depend on the external cues of light and dark. (Bodily cycles are more stable than the timing of sunrise and nightfall in those latitudes where seasons change.)
With the computer, however, it became possible to make and plot the multiple readings that track a great many more biological processes and to discover previously unsuspected periodicities. Almost everything in the body, it was discovered, fluctuates rhythmically: the secretion of adrenaline and other hormones, the manufacture of proteins, the operation of organs such as the kidneys and liver, the presence of various chemical neurotrans-mitters in the brain. White blood cells increase and decrease by as much as 50 percent, an observation which may lead to important ways of understanding—and manipulating—the body’s ability to fight infection.
Furthermore, the computer has revealed regular rhythms that span periods shorter or longer than the simple twenty-four-hour daily clock provided by the Earth’s rotation. One major surprise comes with the discovery that many cycles have a seven-day pattern. In humans, weekly rhythms have been found in pulse, heartbeat, temperature, the number of red blood cells, and the fluctuation of several chemicals and hormones. From a medical standpoint, the seven-day rhythms in the body’s response to certain bacteria and other foreign materials are highly significant. Before penicillin, doctors knew that the crisis in pneumonia came on the seventh or ninth day; malaria has a seven-day curve; and in patients with kidney transplants the immune system is most likely to reject the new organ at regular intervals that come one week, two weeks, three weeks, and four weeks after the operation.
This discovery is intriguing because it challenges received knowledge about the construction of the calendar. The year and the lunar month arose from astronomical observation, but shorter subdivisions of time varied widely in the ancient world. Yet it cannot be that human bodies have simply become accustomed to the workweek/weekend rhythm of the past few centuries and adapted to it; seven-day cycles are much older than human beings and appear in some of the most primitive organisms that have been examined. It is possible, then, that the Jewish calendar which established the seven-day week was an intuitive externalizing of internal rhythms: the sole example of a standardized time measurement based on the human body rather than the...