More concerning thermodynamics-
Let me begin by addressing two commonsense notions: (1) you cannot get something from nothing, and (2) the order of the universe requires the pre-existence of an active intelligence to do the ordering. I will leave it to the theologians to explain how the postulate of a creator God solves the problem of creation ex nihilo, since God is something that, itself, must have come, uncreated, from nothing. Instead I will address the physics issues implied by the creation of the universe from nothing. In physics terms, creation ex nihilo appears to violate both the first and second laws of thermodynamics.
The first law of thermodynamics is equivalent to the principle of conservation of energy: the total energy of a closed system is constant; any energy change must be compensated by a corresponding inflow or outflow from the system.
Einstein showed that mass and energy are equivalent, by E=mc2. So, if the universe started from “nothing,” energy conservation would seem to have been violated by the creation of matter. Some energy from outside is apparently required.
However, our best estimate today is that the total energy of the universe is zero (within a small zero point energy that results from quantum fluctuations), with the positive energy of matter balanced by the negative potential energy of gravity. Since the total energy is zero, no energy was needed to produce the universe and the first law was not violated.
The second law of thermodynamics requires that the entropy, or disorder, of the universe must increase or at least stay constant with time. This would seem to imply that the universe started out in a greater state of order than it has today, and so must have been designed.
However, this argument holds only for a universe of constant volume. The maximum entropy of any object is that of a black hole of the same volume. In an expanding universe, the maximum allowable entropy of the universe is continually increasing, allowing more and more room for order to form as time goes by. If we extrapolate the big bang back to the earliest definable time, the so-called Planck time (10-43 second), we find that universe started out in a condition of maximum entropy—total chaos. The universe had no order at the earliest definable instant. If there was a creator, it had nothing to create.
Note also that one cannot ask, much less answer, “What happened before the big bang?” Since no time earlier than the Planck time can be logically defined, the whole notion of time before the big bang is meaningless.
Furthermore, within the framework of Einstein’s relativity, time is the fourth dimension of spacetime. Defining this fourth dimension as ict, where t is what you read on a clock, i = sqrt(-1), and c is the speed of light, the coordinates of time and space are interchangeable. In short, time is inextricably intertwined with space and came into being “when” or “where” (language is inadequate to mathematics here) spacetime came into being.
So, where did the order of the universe come from, if it did not exist at the “beginning”? Where did the laws of physics come from, if not from some great lawgiver? We are now beginning to grasp how the laws of physics could have come about naturally, as the universe spontaneously exploded in the big bang.
To understand this, we first have to recognize the prejudice that is built into the whole concept of physical law. When Newton developed mechanics and gravity, the Judeo-Christian notion of God-given law was already deeply engraved in his thinking, by his culture. Even today, science is interpreted by public, media, and scientists alike as the process of learning the “mind of God.”
However, the laws of physics, at least in their formal expressions, are no less human inventions than the laws by which we govern ourselves. They represent our imperfect attempts at economical and useful descriptions of the observations we make with our senses and instruments. This is not to say we subjectively determine how the universe behaves, or that it has no orderly behavior. Few scientists deny that an objective, ordered reality exists that is independent of human life and experience. We simply have to recognize that the concept of “natural law” carries with it certain metaphysical baggage that is tied to our traditional, pre-scientific modes of thought. We are going a step beyond logic to conclude that the existence in the universe of order, which we conventionally label as the laws of nature, implies a cosmic lawgiver.
We are gradually learning that several of the laws of physics, those that seem the most universal and profound, are in fact little more than statements about the simplicity of nature that can almost go unsaid. The “laws” of energy, momentum, and angular momentum conservation have been shown to be statements about the homogeneity of space and time. The first law of thermodynamics, conservation of energy, results from there being no unique moment in time. Conservation of momentum follows from the Copernican principle that there is no preferred position in space. Other conservation laws, such as charge and nucleon number, also arise from analogous assumptions of simplicity.
For the mathematically inclined, the conserved quantities are generators of the symmetry transformations involved. A homogeneous universe, one with a high level of symmetry, is the simplest of all possible universes, just the kind we would expect to happen by accident. In such a universe, many conservation laws will automatically exist.
In general, the conservation laws need no explanation beyond the mathematical symbols used to represent the corresponding symmetry. On the other hand, an observed violation of a conservation law would demand an explanation, for then we would have evidence for a deviation from simplicity and homogeneity. To explain this deviation, we have to go beyond the assumptions that require the fewest parameters, that is, are the most economical.
By an equally simple but somewhat different argument, the second law of thermodynamics is found not to be some underlying principle of the universe, but rather an arbitrary convention we humans make in defining the direction of time. Nothing in known fundamental physics forbids the violation of the second law. No mechanical principle prevents the air emptying from a room when you open the door, killing everyone inside. Physics does not forbid a human from growing younger or the dead rising! All that has to happen for these “miraculous” events is that the molecules involved are accidentally moving in the right direction at the right instant. Of course these miracles are not observed to happen except in fantasies, but only because they are so highly unlikely.
We introduce the second “law” to codify what all of human experience testifies, that air does not empty from a room, people do not grow younger, and the dead do not rise. But these events are not impossible, just highly improbable. Influenced, like Newton, by our culture, we falsely state that these unlikely events cannot happen because the second law “forbids” them from doing so.
The second law of thermodynamics, along with the arrow of time and the notions of causality and determinism, arise as statistical statements about the likelihood of events that emerge as principles we invent to describe the world of everyday experiences.
Other, more complex and less universal laws of physics appear to arise from spontaneously broken symmetries. When a quantity such as momentum is observed not to be conserved, we introduce the notion of a “force” to break the corresponding spatial symmetry. By this means, the force laws and other principles that give structure to the universe arise as spontaneously broken symmetries—accidental, uncaused events that occurred in the first fraction of a second of the big bang as the expanding universe cooled. The process can be likened to the formation of structure in a snowflake from water vapor, or the magnetizing of a bar of iron cooled below the Curie temperature.