4. The Anthropic Principle
Aristotle and Ptolemy believed that the earth lay at the center of the solar system and the universe. Aristarchus and Copernicus, on the other hand, argued that the solar system was heliocentric. This shift in the conception of the earth's "importance" and hence mankind's supposed place in the universe, was a revolutionary and shocking thought to the people of that time. Today we know that not only does the earth accompany other planets in orbit around the sun, but also the Milky Way galaxy is but one of millions of other galaxies in the universe. Where do we belong? An attempt to reinsert humans as a central aspect of the cosmos is stated in the Anthropic Principle. There are different "versions" of this principle, the interpretation of which provides a point of view from which to examine our place within the expanse of the universe.
The Strong Anthropic Principle
This principle strictly defines any universe as one which necessarily produces intelligent or sentient beings, who are able to observe it. Another way of stating it would be that the structure and particles of the universe are essentially fixed by conditions which specify that at some point an intelligent observer will emerge. Most scientists and philosophers today do not adhere to this version of the Anthropic Principle, because it is simply too rational and limiting when placed against what we know about the construction of the universe. The laws of quantum mechanics, for example, clearly point toward the uncertainty of events on the molecular level, and therefore in all creation. How could we know that the universe exists only to support intelligent life? And what if a minute change in the order of events occurred, such that the evolution of life became impossible? Is not evolution a combination of chance and selection, impossible to predict and complex beyond imagining? And is there intelligent life outside of the human race? Even animals on our earth are in their own way sentient and intelligent; might not a life form exist which does not subscribe to our own laws of physics and chemistry? The strong Anthropic principle does indeed display a bias toward humans as the pinnacle of intelligent life, and the arrogance it describes simply has no part in our modern understanding of the universe as a whole. Other versions of the principle may provide a more palatable explanation.
The Weak Anthropic Principle
"Because there are observers in our universe, the universe must possess properties which include these observers." This "variety" of the principle only insists that the universe that we know was constructed in such a way that life within it became possible. It is therefore less constricting and narrow than the strong principle, other life forms may still find room to exist, and the possibilities of multiple and unimaginable universes are not ruled out. For many people, this version is easier to swallow. The outright arrogance of the strong principle is watered down, and mankind is left with a sense of importance which may be justified within our own universe.
This theory, an even stronger version of the Strong Anthropic Principle, states that the conditions of the universe which allow humans to exist were created on purpose by God. With this version, God is placed in position "behind the curtain," as Someone who decreed that the universe come into being, and who is responsible for the creation of man in His image. Instead of denying that God exists, as so many scientific theories seem to do, this principle sets a place for Him. For many people who find their need for a reason and for order supplied by the idea of God, this theory is the only option. Here is given a purpose for humanity; a higher calling and a noble beginning, in contrast to emerging out of "primordial ooze" which some people find unpleasant to consider. Perhaps the thought of a God who created the universe for the benefit of humanity makes some people feel secure inside the depths and vastness of the cosmos; it is comforting to believe that a kind and loving God is there to be with us.
The Participatory Anthropic Principle
"No universe can exist unless it contains conscious observers." Again, this version seems to assume or point toward humans as the only intelligent beings that the universe has to offer. The arrogance of the strong anthropic principle is evident, in an even more simplistic statement which seems harsh and unforgiving. There is no room for compromise or imagination here; the universe exists only in participation with its observers.
The Final Anthropic Principle
This version is perhaps the most intriguing and controversial in its statement that once intelligence emerges, it will never perish. How fascinating to consider that the dawn of human intelligence, as is clearly indicated, was the beginning of perpetual life in the universe! Could perpetual mean eternal? How might the spiritual aspect of our humanity deal with this question? Could this principle be interpreted in a manner excluding human beings? If so, does that mean that we must accept the possibility that we cannot control the circumstances which may lead to our extinction as a species?
Many important and interesting ideas are raised by these versions of the Anthropic Principle, all of which are worth consideration, if only to give us an informed perspective on our development as human beings: a species among species on a planet among planets in a galaxy among millions of other galaxies spread across the vast expanse of the universe. Maybe our universe itself is one among millions...
It is for some people a disturbing thought to consider that we cannot easily define what is real. Webster's Dictionary states that reality is "something that is real; what is not imaginary, fictitious, or pretend; what has objective existence." But these definitions are hardly satisfactory, for how do we define the "something" and the "what"? The question, "What is reality?" has no easy answer, and it is one which has plagued humanity for centuries.
We can use our senses to perceive the world around us; is this all of reality? We can use our imaginations to wonder about other possible worlds; is this reality, or could it be? What about the reality of dreams?
In science we use models to describe data, utilizing the utmost precision and accuracy to understand the "real" phenomenon. But we can never reach reality with models. The problem is that many times, the model is mistaken for reality. Einstein noted that because of our inability to "think outside the box," we are sometimes blinded by our perceived certainty of mathematical and scientific models. We need to consider also the inductive, experiential, and non-scientific models which are a part of our everyday lives as human beings. It is a fact that a scientific model can never be proved; only disproved. And so our models, in which we trust, can only show relationships, and contrary to what most people would like to believe, cannot be proven beyond the shadow of a doubt. Scientific knowledge is not illusion, but it is a set of assumptions and conclusions based on models which are not infallible. What a scary thought for those who place all their faith in science! On the other hand, this makes science an ever evolving and never-ending enterprise...
In the paradox of Plato's Cave, we find prisoners who are chained, for the duration of their lives, to a wall inside a cave. Their backs are to the fire; they cannot directly see the light, only shadows on the wall. What they perceive as reality is nothing but a reflection of the true reality. What if we also have our "backs to the fire"? Our experience of reality is all we have to go by; what if we are not seeing the whole picture? The theory of "progressive reality" in fact states that each individual possesses their own version of reality, which is limited and yet true for that person. How can we decide upon a definition of the "true reality" which must exist for all of us? Is there a reality outside of our perception?
By way of example, consider the color blue. Do we all see the same color? Is there a reality in which there is blue, or is it only real in our perception of it? In physics we are able to use a spectrometer to determine the wavelength of light; its frequency tells us that it is blue. But without the spectrometer, is the "blueness" still apparent? Color, in the words of science, is a reflection. Without light, it would not be blue, but the potential for blue is still there. Is it sometimes blue, or all the time? Is there something in the color blue that is blueness? Is there really an underlying reality, beyond what we perceive, in the universe that we can understand?
Can we define reality with words or only experience it? At the heart of our problem lies the fact that our language is insufficient to the task of defining reality. When we try to understand it, and use words to define it, we separate "it" from the reality surrounding everything. Language takes things apart, and isolates them so that they can be examined by our logical minds. Our perceptions of reality are a part of reality, and we cannot take ourselves out of the picture. We end up using circular arguments and definitions, which are not satisfactory, but are the only representations that we can construct for the concept of "reality." So why keep after the question? We want to know about reality because it bothers us that we cannot define it. It keeps us interested in questions and answers. We want to find meaning in our reality, and we have the idea that there is always something beyond what we think, know, understand, and experience in the universe.
When does probability collapse and become something we can describe? In quantum mechanics you can describe something as a wave function or a particle, depending on which way you decide to observe it. Through experimentation, you "collapse" it into one or the other. You have interacted with it and created an entity that you can describe. But reality cannot be collapsed, because we are a part of it--we are the wave functions and particles of the universe! We may never decide upon one right answer to the question, "What is reality?", and maybe that is a good thing. Maybe we need that uncertainty to just keep us guessing...
A Time Line
Aristotle may have regarded time as cyclical in that, when the heavenly bodies returned to the positions they held at the beginning of the world, time would start over, like replaying a CD. In about the 4th century, St. Augustine sought to linearize time, relating it to the crucifixion of Christ, an event not to be repeated. He also introduced some ideas that time might be subjective, and not merely physical or tied to the "heavenly bodies." In the 17th century, Sir Isaac Newton stoutly maintained in England that time flows uniformly of its own accord, independently of human minds and all material objects, like a long broad river which would never change course or reverse. But in Germany, Newton's archrival, Baron Wilhelm von Liebnitz, regarded time simply as the order of succession of phenomena. Scientists and philosophers alike continued to struggle with the definition and meaning of time itself for many years.
Then, in the 18th century, the German philosopher Immanuel Kant picked up Augustine's notion that time is a feature of the way men's minds visualize the external world and is not a characteristic of reality itself. That was still an interesting idea, but it did not prevent Newton's concepts from prevailing--until 1905. In that year, when Albert Einstein announced his Theory of Special Relativity, all fundamental physical concepts--including time--had to be reexamined. For most terrestrial purposes, Newton's laws continued to work very well. Scientists continued their efforts to establish repeatable standards, including the adoption of the rate of oscillation of the cesium atom as the definition of the "atomic second." Apparently, the cesium atom has very stable habits.
Since then, the "General Conference of Weights and Measures" has ordained that "one second" of time shall henceforth be the interval required for 9,162,631,770 oscillations of the cesium atom. Sixty seconds shall define one minutes, and sixty minutes one hour. So what is left to discuss about the nature of time?
Einstein's propositions in 1905, and again in 1915, have created some real waves in Newton's smoothly flowing river of time. Moreover, some later scientists have proposed concepts of time, which might have taxed even the imagination of Einstein.
According to special relativity, each inertial system in the universe has its own time parameter. So the intuitive concepts of absolute time and absolute simultaneity, as espoused by Newton and others, do not exist in special relativity! And with the advent of space travel and the forecasting of the trajectories of asteroids, relativistic considerations have become important to our lives as well as to our intellects. Even the possibility of "negative time" can no longer be disregarded, because the laws of physical mechanics operate equally well if " - t" is substituted for "t" in equations dealing with rate or time.
With regard to going backward in time, Einstein's Theory of General Relativity, announced in 1915, has provided a clue. He showed that both space and time are curved, and that the curvature of "space-time" can become extreme in the neighborhood of very massive objects. This opened the door to the concept of tunnels connecting distant regions of space-time. Possibly one could even use a so-called "worm-hole" to travel into one's own past! Another suggestion for time travel, by Richard Gott in 1991, required the use of "cosmic strings." These are described as thin strands of energy millions of light years long, and have been predicted by some theories of particle physics but not yet observed in the universe. Half the mass-energy of a galaxy would be required for implementation of time travel!
Although Einstein's theories are not psychological in nature, Stephen Hawking has, to a limited extent, revisited subjective concepts such as those of Kant in his writings (see Stephen Hawking, A Brief History of Time). For evaluation of the direction of time, he has proposed three distinct "arrows": thermodynamic, psychological, and cosmological. Hawking's "thermodynamic" arrow seems to draw upon the "information theory" developed by Claude Shannon in the late 1940's, primarily for communications purposes. As a criterion for distinguishing useful "information" from predictable and useless signals, Shannon borrowed from thermodynamics the term "entropy." To him, entropy is a measure of spontaneity or degree of meaningful freedom, as distinguished from rote "organization." It also happened that some of Shannon's probability concepts took mathematical forms similar to the concepts defining thermodynamic entropy. But Hawking treats Shannon's "entropy" as if it really were rooted in physical thermodynamics. In proposing his "psychological" arrow, Hawking once again departs from his usual high standard of rigor. But turning to his "cosmological" arrow, Hawking is undoubtedly right that we wouldn't be here if the universe were not expanding at its present rate. And we certainly won't be here if and when the universe enters a contracting phase. How would time change if the matter in the universe started decelerating?
(Summary by Robert Crooks)