The history of science can be viewed as the recasting of phenomena that were once thought to be accidents as phenomena that can be understood in terms of fundamental causes and principles
All these phenomena and many more, once thought to have been fixed at the beginning of time or to be the result of random events thereafter, have been explained as necessary consequences of the fundamental laws of nature—laws discovered by human beings.
Dramatic developments in cosmological findings and thought have led some of the world’s premier physicists to propose that our universe is only one of an enormous number of universes with wildly varying properties, and that some of the most basic features of our particular universe are indeed mere accidents—a random throw of the cosmic dice. In which case, there is no hope of ever explaining our universe’s features in terms of fundamental causes and principles.
Physicists call the totality of universes the “multiverse.”
Alan Guth, a pioneer in cosmological thought, says that “the multiple-universe idea severely limits our hopes to understand the world from fundamental principles.”
However, two theories in physics, eternal inflation and string theory, now suggest that the same fundamental principles from which the laws of nature derive may lead to many different self-consistent universes, with many different properties.
Evidently, the fundamental laws of nature do not pin down a single and unique universe. According to the current thinking of many physicists, we are living in one of a vast number of universes. We are living in an accidental universe. We are living in a universe uncalculable by science.
The theory of inflation proposes that when our universe was only about a trillionth of a trillionth of a trillionth of a second old, a peculiar type of energy caused the cosmos to expand very rapidly. A tiny fraction of a second later, the universe returned to the more leisurely rate of expansion of the standard Big Bang model.
if the values of some of the fundamental parameters of our universe were a little larger or a little smaller, life could not have arisen.
The strengths of the basic forces and certain other fundamental parameters in our universe appear to be “fine-tuned” to allow the existence of life. The recognition of this finetuning led British physicist Brandon Carter to articulate what he called the anthropic principle, which states that the universe must have the parameters it does because we are here to observe it.
If such conclusions are correct, the great question, of course, is why these fundamental parameters happen to lie within the range needed for life. Does the universe care about life? Intelligent design is one answer. Indeed, a fair number of theologians, philosophers, and even some scientists have used fine-tuning and the anthropic principle as evidence of the existence of God.
The multiverse offers another explanation. If there are countless different universes with different properties—for example, some with nuclear forces much stronger than in our universe and some with nuclear forces much weaker—then some of those universes will allow the emergence of life and some will not.
From the huge range of possible universes predicted by the theories, the fraction of universes with life is undoubtedly small. But that doesn’t matter. We live in one of the universes that permits life because otherwise we wouldn’t be here to ask the question.
If the multiverse idea is correct, then the historic mission of physics to explain all the properties of our universe in terms of fundamental principles—to explain why the properties of our universe must necessarily be what they are—is futile, a beautiful philosophical dream that simply isn’t true. Our universe is what it is because we are here.
two teams of astronomers announced that some unknown force appears to be jamming its foot down on the cosmic accelerator pedal. The expansion is speeding up. Galaxies are flying away from each other as if repelled by antigravity.
Physicists have named the energy associated with this cosmological force dark energy.
based on our observations of the accelerating rate of expansion, dark energy constitutes a whopping three quarters of the total energy of the universe
On one thing most physicists agree: If the amount of dark energy in our universe were only a little bit different than what it actually is, then life could never have emerged.
Here we have a clear example of fine-tuning: out of all the possible amounts of dark energy that our universe might have, the actual amount lies in the tiny sliver of the range that allows life. There is little argument on this point.
Our particular universe is one of the universes with a small value, permitting the emergence of life. We are here, so our universe must be such a universe. We are an accident. From the cosmic lottery hat containing zillions of universes, we happened to draw a universe that allowed life. But then again, if we had not drawn such a ticket, we would not be here to ponder the odds.
In the theory of eternal inflation, the dark energy field has many different values at different points of space, analogous to lots of marbles sitting in lots of dents on the cosmic table. Moreover, as space expands rapidly, the number of marbles increases. Each of these marbles is jostled by the random processes inherent in quantum mechanics, and some of the marbles will begin rolling across the table and onto the floor. Each marble starts a new Big Bang, essentially a new universe. Thus, the original, rapidly expanding universe spawns a multitude of new universes, in a never-ending process.
In the past few years, however, physicists have discovered that string theory predicts not a unique universe but a huge number of possible universes with different properties. It has been estimated that the “string landscape” contains 10500 different possible universes.
Not only must we accept that basic properties of our universe are accidental and uncalculable. In addition, we must believe in the existence of many other universes. But we have no conceivable way of observing these other universes and cannot prove their existence. Thus, to explain what we see in the world and in our mental deductions, we must believe in what we cannot prove.
http://www.harpers.org/archive/2011/12/0083720