IN A CONTEMPLATIVE moment, you may have watched a clock precisely tick off the seconds. At the same time you may have subjectively sensed one moment gently and indistinguishably merge into the next.
This experience expresses two aspects of time, one of accurate measurement, the other of human sensation.
The notion that time is rational and quantitative as well as intuitive and subjective has haunted and fascinated thinkers for centuries. It has also haunted me, a physicist, and prompted me to examine time concepts from the extreme perspectives of physics, the "hardest of sciences," and religion, the "softest of humanities."
I have looked in particular at comparisons between concepts of time in modern physics and those in Hindu, Buddhist, Tao and Judeo-Christian religious traditions. There are interesting similarities between what physicists are reporting in detail today and what ancient religious mystics painted in broad strokes with an insight that is truly impressive.
The similarities arise in six categories: the beginning of time, the duration of time, the end of time, timelessness, the irreversibility of time and the interrelatedness of time and space.
Let us start with the beginning of time, which for most physicists was first described by what is known as the Big Bang Theory (BBT), the father of present-day theories.
First, according to the BBT, there was an instant at which the universe began with a colossal explosion.
Second, the evolution that came with the expansion and cooling of the universe occurred in stages, starting at extremely high temperatures with the most elementary particles and very gradually reaching the present stage of cooling where atoms, molecules, galaxies, organisms and humans can exist.
Third, during the earlier stages a tremendous amount of energy was released in the form of light, a degraded remnant of which is still experimentally detectable today.
Now let us compare these three general aspects of the BBT with the first verses of the Bible: "In the beginning God created the heavens and the earth . . . And God said, 'Let there be light'; and there was light." These words are followed by a description of the remaining of the six days of creation. The three features of the BBT are all found in the Genesis story: the moment of creation, light and creation in stages.
According to mainstream biblical scholarship, elements of the Genesis story derived from Babylonian and Canaanite creation myths. These are but two among a variety of such myths -- often with the element of light -- found in other primitive cultures such as the Navaho, Pueblo, Mayans and Zuni in North America, and the Polynesians, Tahitians, Maoris and aborigines in the South Pacific.
For example, in the Maori myth of creation by the god Io, we read: "Io dwelt within the breathing-space of immensity. The universe was in darkness . . . . And he began by saying these words: . . . 'Let there be light unto Tawhito, a dominion of light, a bright light,' and now a great light prevailed."
I find this remarkable. How did these people know that there was a moment of creation? Why did some of them think light was associated with it, or that things happened in stages and not all at once?
Perhaps the anthropologists have a clue. They tell us that the human brain, after having experienced an incredible evolutionary growth of ten cubic inches every 100,000 years, has not changed significantly in the last 100,000. Men and women of 6,000 years ago may therefore have been just as intelligent as we. What they lacked in modern scientific ability, they may have more than made up for in spiritual insight.
By the early part of the previous millenium some of this insight had reached a matured state. In his "Confessions," St. Augustine develops in considerable detail his concepts of God's time. He clearly states that before God created the world, there was no time. God created the world and time along with it; God is outside of time. In essence, he agrees with many physicists, such as theoretical physicist John Wheeler, who say that time did not exist before the Big Bang.
Other time-related questions associated with the Big Bang arise from the burning and still-unsettled issue of whether the universe is "open" or "closed." That is, will it expand forever, in which case it is an "open universe," or is there enough mass in the universe so that gravity will reverse the expansion and ultimately turn the universe into a super-dense black hole, or "Big Crunch," as Wheeler puts it?
The latter is an abbreviated scenario for a "closed universe." In the Big Crunch, time again may cease to exist as it may have before the Big Bang. But will it? Many credible physicists, including Nobel laureate Andrei Sakharov, take seriously the possibility that the crunch will be followed by another bang, starting another cosmic cycle.
This possibility presents an interesting parallel to the cyclic cosmology envisioned in Hindu scriptures called the Puranas. Their largest cosmologic time unit is known as a kalpa, which is 4.32 billion years. It is a day in the life of Brahma, the creator. With a night of the same duration, and a life of 100 Brahmic years, this yields a total of 311,040 billion years, after which total dissolution occurs for a Brahmic century. Then the cycle begins again.
Such cycles are symbolized by three gods: Brahma, the creator of the universe, Vishnu, its preserver and Shiva its destroyer. They are realizations of the supreme deity, Brahman, who is changeless, indescribable, attributeless and beyond time, space and the universe. Hinduism is the only major religion which specifies time periods of such colossal scope. What is striking is that the time scales -- billions of years -- are comparable to the scale given by the scientifically estimated age of the universe, about 18 billion years.
Cyclical cosmologies also characterize the Mahayana Buddhist and Taoist religions. Although no times are specified, the Tao tradition sees the world as being created from the Absolute Tao and receding back to it. But just as with Brahman, the Absolute Tao is ineffable, transcendent and outside of time; it is the timeless Non-Being that sustains the universe. Thus both Brahman and the Absolute Tao attest to the reality of timelessness.
The notion of timelessness is also apparent from the contention of St. Augustine and John Wheeler that there was no time before the creation instant. If the universe happens to be closed as well as non-cyclical, there may be none after the Big Crunch.
Another aspect of time addressed by both science and some religions is its irreversibility. Common sense might argue that it is obvious that time is irreversible. But it has long been the observation of physicists that almost all physical phenomena in the microscopic world could occur in a context in which time moves backward as well as forward. Reconciling this behavior in the microscopic world with our day-to-day human experience of time as irreversible has occupied the thought of physicists and philosophers for years.
Time's irreversibility has been gauged in several ways.
The continuously expanding universe is like a giant clock ticking off the eons and defining what physicist and natural philosopher Sir Arthur Eddington called the "arrow of time."
Physicist David Layzer calls the arrow of time associated with the expanding universe the "cosmological arrow." The inherent characteristic of physical nature to gradually disintegrate into a greater state of disorder -- more precisely described by a thermodynamic quantity called entropy -- is the basis for what has been labelled the "thermodynamic arrow."
On the other hand, what Layzer calls the "historical arrow" associates the irreversibility of time with the growth of order, as in crystals, organisms, and humans.
For comparison let us now look at some religiously based arrows.
The Judeo-Christian arrow derives from the belief in a single non-repeatable creation event, and that time is proceeding unidirectionally toward a day of judgment, such as the coming of the Messiah for the Jews and Christ's second coming for the Christians. The linear sense of time associated with this belief originated with early Israel's developing commitment to a god of history in contrast to one of cyclical nature as was characteristic of the Canaanites.
French theologian Teilhard de Chardin gives a modern interpretation of the Judeo- Christian arrow and sees an irreversible direction or "axis" inherent in the evolution of the universe. In this evolution through inanimate matter, then animate matter or life, then cognizant matter or mankind, Teilhard sees a progression to what he terms the Omega Point, which may be associated with the Christian End, or Day of Judgment.
Alfred North Whitehead, whose philosophy embraces both physical and religious concepts, sees a world propagated by units or quanta of experience (for Whitehead even inanimate matter can experience) known as "actual occasions," whose occurrences are influenced but not dictated by God. These "actual occasions" are characterized by a certain intermixing of time and space, and, having happened, can never happen in the same way again. This clearly implies a unidirectionality or arrow of time.
Whitehead's thought also leads us to our final aspect of time, its interdependence with space, which is one of the significant features of Einstein's theory of relativity. It was perhaps expressed most cogently by Hermann Minkowski, whose work Einstein adapted in his theory: "Henceforth space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality."
Interdependence also is expressed by Buddhist sages -- a point made by Fritjof Capra in his book, "The Tao of Physics."
The Tibetan Buddhist mystic Lama Govinda, discussing the meditative experience, speaks of "a state of mutual interpenetration . . . in which time and space are integrated." D. T. Suzuki, scholar of eastern religions, elucidating the meditative practice of a Mahayana Buddhist school, stated, "There is no space without time, no time without space; they are also interpenetrating."
Do these similarities between religious and physical views of time that I have discussed imply that there may be an underlying unity? Possibly, but not necessarily. Perhaps we could try another approach to achieve some kind of conceptual unity using a generalization of what is known as the Complementarity Principle. It was first enunciated by one of the founders of modern physics, Niels Bohr.
He applied the principle to the duality exhibited by all of the inhabitants of the microscopic world from protons and electrons to massless units of light known as photons. Depending on the measuring instrument used, any inhabitant will appear either as a particle or a wave but never both simultaneously. For example, if, observing an electron with one kind of instrument, the physicist sees it as a wave, he may with another instrument see it as a particle. Bohr maintained that the wave and particle forms were irreducible and mutually exclusive, but complementary, modes of a single phenomenon.
I believe a case can be made for applying a generalization of the principle to the duality presented by the objective and subjective, or more particularly, by the physical and religious views of time.
There may also be a possibility for unity through a further study of the human brain, particularly its left and right characteristics. For example, psychologists have already found that the left brain is dominant in establishing the temporal order of two closely spaced events, while the right brain possesses a better sense of time durations as well as of velocity and accelerations.
Despite these attempts at finding some unity in the concepts of time, there is the haunting thought that one or the other is really the true view. Some would argue that the rational scientific view is the only true one, for it is only by a scientific approach that one can find a universally agreed-upon view of time, free from individual human bias.
But as Longfellow wrote:
"What is time? The shadow of the dial, the striking of
the clock, the running of the sand, day and night,
summer and winter, months, years, centuries -- These are
but arbitrary and outward signs, the measure of Time,
not Time itself. Time is the life of the soul."
Obviously, clear answers to the mystery of time are hard to come by. It will probably always challenge us with fascinating, uncharted and ever-deeper levels for exploration, as part of our search for meaning. And my attempts to find answers by comparison of physical and religious time concepts will probably continue with impetus provided by the words of Sir Arthur Eddington:
"In any attempt to bridge the domains of experience belonging to the spiritual and physical sides of our nature, time occupies the key position."