Sunday, November 23, 2008

What is time?

"The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' (I found it!) But 'That's funny ..." Isaac Asimov

As I sit on a Sunday morning, pondering about fast the weekend went by and how less the time seems to be when you are having fun… a thought struck me – what is time? Often the immediate concept that comes to mind is a clock, watch or a calendar, but what really is time?

According to John Sankey, to physicists, time is defined by quantum mechanics. A photon with energy h (Planck's constant) behaves as though it were oscillating once per second. Modern atomic clocks are based on this. Time direction is something else. It is based on information, which sits uneasily in the world of physics. But, any quantum system must have an arrow of time.

You often hear: “I have no time.”, “Time is money.”, “I need to be on time” and so on.

I have read through some scientific literature and what the scientific community considers as time if even more confusing than our everyday common sense notions about it, for example the Einstein theory of relativity makes the subject for ordinary people just even more confused.

What if time were to stop?

As L. Ron Hubbard (1951) had put it - The illusion called time is composed of altering of the particles position in space” and “Alteration is the basic manifestation of time. Well, he was much more of fantasy novel writer than actual scientist (some may dispute the fact).

Everything moves, all the time. Time is measured from instruments which from beginning come from natural movements such as the sun and the planet as well as the moon. When we think of time we tend to think of the ways in which we measure the passing of time, such as a clock or watch, or perhaps a measured interval of time such as an hour or minute, but not of time itself. So what is time? Exactly what is it that we are measuring?

We can begin to answer the question with the basic description that we are measuring the interval between events, using units that we have chosen for the purpose. We may say, for example, that the next train will be due in 5 minutes. While this information may be very useful for telling us how late the train is when it eventually arrives, it does nothing to describe just what it is that we are measuring. We want to know exactly what the 'interval' is.

Time can seem as solid as a rock. In fact, it's a lot more squishy. Our calendars are imperfect. We need a leap day to keep them in line with the seasons, and even so, time will eventually get away from us. "If you feel there aren't enough hours in a day, just wait," says Max Tegmark, a cosmologist at the Massachusetts Institute of Technology. "In a few hundred million years, tidal friction will have slowed Earth's rotation to make the day 25 hours long."

If that doesn't make your head spin, consider that in physics, motion alters time; in psychology, different stimuli alter our perception of time; and in philosophy, there's disagreement on whether time is even real. "In terms of our inner lives, no time exists except for what is happening in the present moment," says Joan Halifax Roshi, a Zen Buddhist teacher.

Whew!

And I thought time was such a simple matter to ponder about…

In physics and other sciences, time is considered one of the few fundamental quantities. Time is used to define other quantities – such as velocity – and defining time in terms of such quantities would result in circularity of definition. An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, is highly useful in the conduct of both advanced experiments and everyday affairs of life. The operational definition leaves aside the question whether there is something called time, apart from the counting activity just mentioned, that flows and that can be measured. Investigations of a single continuum called space-time brings the nature of time into association with related questions into the nature of space, questions that have their roots in the works of early students of natural philosophy.

Among prominent philosophers, there are two distinct viewpoints on time.

One view is that time is part of the fundamental structure of the universe, a dimension in which events occur in sequence. Time travel, in this view, becomes a possibility as other "times" persist like frames of a film strip, spread out across the time line. Sir Isaac Newton subscribed to this realist view, and hence it is sometimes referred to as Newtonian time.

The opposing view is that time does not refer to any kind of "container" that events and objects "move through", nor to any entity that "flows", but that it is instead part of a fundamental intellectual structure (together with space and number) within which humans sequence and compare events. This second view, in the tradition of Gottfried Leibniz and Immanuel Kant, holds that time is neither an event nor a thing, and thus is not itself measurable nor can it be traveled.

According to Lee Smolin, The debate between absolute and relational time echoes down the history of physics and philosophy, and confronts us now, at the end of the twentieth century, as we try to understand what notion of space and time is to replace Newton's. If there is no absolute time, then Newton's laws of motion don't make sense. What must replace them has to be a different kind of law that can make sense if one measures time by any clock. That is, what is required is a democratic rather than an autocratic law, in which any clock's time, imperfect as it may be, is as good as any other's. Leibniz was never able to invent such a law. But Einstein did, and it is indeed one of the great achievements of his theory of general relativity that a way was found to express the laws of motion so that they make sense whichever clock one uses to embody them with meaning. Paradoxically, this is done by eliminating any reference to time from the basic equations of the theory. The result is that time cannot be spoken about generally or abstractly; we can only describe how the universe changes in time if we first tell the theory exactly which real physical processes are to be used as clocks to measure the passage of time.

The problem is that general relativity is only half of the revolution of twentieth-century physics, for there is also the quantum theory. And quantum theory, which was originally developed to explain the properties of atoms and molecules, took over completely Newton's notion of an absolute ideal time.

So, in theoretical physics, we have at present not one theory of nature but two theories: relativity and quantum mechanics, and they are based on two different notions of time.

In the theory of relativity, the concept of time begins with the Big Bang the same way as parallels of latitude begin at the North Pole. You cannot go further north than the North Pole,” says Kari Enqvist, Professor of Cosmology.

One of the most peculiar qualities of time is the fact that it is measured by motion and it also becomes evident through motion.

According to the general theory of relativity, the development of space may result in the collapse of the universe. All matter would shrink into a tiny dot again, which would end the concept of time as we know it.

No general agreements here, although the search for the grand unified theory is on the achievement does not appear to be any closer still.

There is of course, like anything else under the purview of human thought, an alternate, more human approach towards time…

Spiritual guide and alternative medicine expert Deepak Chopra, who warned of the dangers of a hectic lifestyle. "People who feel that they are 'running out of time' have speeded up their biological clocks," says Chopra. "They have faster heart rates and jittery platelets with high levels of adrenaline. When they drop dead from a premature heart attack, they have literally 'run out of time.'"

Perhaps the most surprising thing we heard about time came from a scientist and entrepreneur who studies aging. "Time has little impact on biology," says Michael West, a gerontologist who teaches at the University of California, Berkeley, and founded the biotech company Geron. That sounds reassuring at first--but it's only because we're pre-programmed to fall apart anyway. "From a gerontologist's standpoint, biological time is not wear-and-tear, it's a genetic program," says West. "It's sort of like a time bomb. The cells are programmed to last just long enough for us to rear children, and no longer."

If now is both now and forever, as C.S. Lewis suggested, then the religious view may not be so different than the scientific view. Physics tells us that all moments exist equally, at once--it's only our consciousness that distinguishes the present from the past or future.

According to The Internet Encyclopedia of Philosophy, “Time has been studied by philosophers and scientists for 2,500 years, and thanks to this attention it is much better understood today. Nevertheless, many issues remain to be resolved. Here is a short list of the most important ones—what time actually is; whether time exists when nothing is changing; what kinds of time travel are possible; why time has an arrow; whether the future and past are real; how to analyze the metaphor of time's flow; whether the future will be infinite; whether there was time before the Big Bang; whether tensed or tenseless concepts are semantically basic; what is the proper formalism or logic for capturing the special role that time plays in reasoning; and what are the neural mechanisms that account for our experience of time”.

There are 3 competing theories:

--> Presentists argue that necessarily only present objects and present experiences are real, and we conscious beings recognize this in the special "vividness" of our present experience

--> According to the growing-universe or growing-block theory, the past and present are both real, but the future is not because the future is indeterminate or merely potential

--> The third and more popular theory is that there are no significant ontological differences among present, past and future because the differences are merely subjective. This view is called "the block universe theory" or "eternalism."

Although there are theories of how to solve a specific problem about time, it is always better to knit together solutions to several problems. Ideally, the goal is to produce a theory of time that will solve in a systematic way the constellation of problems involving time. What are those problems?

--> One is to clarify the relationship between time and the mind. Does time exist for beings that have no minds? It is easy to confuse time itself with the perception of time.

--> Another problem is to decide which of our intuitions about time should be retained. Some of these intuitions may reflect deep insights into the nature of time, and others may be faulty ideas inherited from our predecessors. It is not obvious which is which. For one example, if we have the intuition that time flows, but our science implies otherwise, then which view should get priority? Philosophers of time must solve the problem of how to treat our intuitions

--> A third problem for a philosophical theory of time is to clarify what physical science presupposes and implies about time. Most all philosophers of time claim that philosophical theories should be consistent with physical science, or, if not, then they must accept the heavy burden of proof to justify the inconsistency

A philosophical theory of time should describe the relationship between instants and events. Does the instant that we label as "11:01 A.M." for a certain date exist independently of the events that occur then? In other words, can time exist if no event is happening? This question or problem raises the thorny metaphysical issue of absolute vs. relational theories of time.

The article is profound in its depth and I strongly recommend reading, though not on a Sunday afternoon, when one is more attuned towards a lazy stroll through time rather than an activity which challenges the one’s intellect and imagination both.

Although we understand that Time is a component of a measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify the motions of objects, Time has been a major subject of religion, philosophy, and science, but defining time in a non-controversial manner applicable to all fields of study has consistently eluded the greatest scholars. Also, throughout my readings, the concept of time, which we all take for granted, is still far from being agreed upon by most of the branches of human thought from Physics to religion. It is profoundly disturbing and humbling to know that we know how to split an atom, reach the moon and gaze at the depth of cosmos, we are still not quite sure what time is… although we can experience its effects on everything we see around us…

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