A logical case for the existence of God:
Scenario #2: 1000 years from now, long after America has been forgotten, a group of people stumbles across Mount Rushmore, sees the faces carved into the rock, and exclaims, “My! What a fantastic coincidence that wind and erosion patterns shaped this rock into the resemblance of four different people’s faces! Aren’t the random forces of nature amazing?!”
Scenario #2: In this scenario, the group’s reaction to and conclusion about seeing the faces on Mount Rushmore is obviously erroneous. Not simply because we know from experience that someone sculpted Mount Rushmore, but because Mount Rushmore is so specific and complex a pattern that it could not have arisen from random, chaotic forces. It had to have been purposefully constructed by an intelligence with a plan in mind for what the finished product would look like.
A system of any kind can be described in terms of its level of complexity and specificity. Complexity refers to a system that is intricate but has no independent pattern, while specificity refers to a system conforming to an independent pattern. The letter “a” is specified without being complex (i.e., it conforms to an independent pattern but is simple). The sequence of random letters “vnskguthwpalfjtibw” is complex without being specified (i.e., it requires a complicated instruction-set to describe but conforms to no independent pattern). If you were to dump a bag of Scrabble tiles on the ground, you would create a very complex string of letters, but it would not be specified. Your pile of Scrabble letters may even occasionally group to form small words, which are specified but not complex. Your tiles, however, will not randomly fall into this paragraph, which is both specified and complex.
Taking our Scrabble analogy to the primordial Earth, it is perfectly rational and feasible to postulate that the "primordial ooze" of the early Earth may have contained many different kinds of amino acids (complexity), just as the Scrabble tiles contain many different random strings of letters. It is also perfectly rational and feasible to postulate that, in our vast sea of random amino acids, some may have joined together to form simple molecular chains (specificity), just as occasionally our scrabble tiles will make a short word.
However, postulating that the randomly distributed amino acids in our primordial sea would chance to join together into large molecular chain structures (complex) that happened to have arranged themselves in such a way as to make themselves capable of self-replication (specified), which would then combine together to form single-celled living organisms (and not just one, but many different types), which would then combine together to form multi-cellular organisms, which would then diversify into many different types of multi-cellular organisms, which would also begin eating one another and, through a random process of genetic mutations and chaotic chance, would happen to lead to the development of an ecosphere that is self-sustaining, contains all the plant and animal species that fill every biological niche that exists today, and includes a species of animal that is intelligent enough to ponder the meaning of its own existence, all on a planet that, randomly driven by gravity and other physical laws, happened to form at the exact right distance and orbit away from a sun that, by chance, is also the exact right size and temperature to support life, is statistically impossible.
Additionally, one of the most important laws of physics is the law of entropy (the second law of thermodynamics), stating that closed systems tend to move from order to disorder and not the other way around. Screws fall out, sidewalks crack, cars break down, clothes get holes, paint peels, hot meals get cold, the yard constantly needs edging, ice melts, it is easy to spend money and hard to earn it, you can never find a matching pair of socks; all examples of entropy at work in the natural world. And the only way that entropy can be overcome is by some external force inputting large amounts of energy into the system. In other words, once salt dissolves in water (i.e. it moves from a solid, ordered crystalline structure to something more randomized and chaotic), it cannot recrystallize itself again on its own, not without an external force putting enough energy into the system to evaporate all the water.
Entropy is one of the most important physical forces in the universe, alongside gravity, electromagnetism, nuclear binding forces, relativity, etc., and without it the universe would not exist. However, the entire hypothetical process of spontaneously generated specified and complex life that was explained in the paragraphs above is that of a disordered and chaotic system organizing itself into a more and more highly organized and ordered system, seemingly violating the law of entropy.
An explanation for this violation of the second law can be attempted on the small scale, because while the universe as a whole is a closed system, the Earth is not. Since there is an external force inputting energy into the system in the form of the sun, scientists will say that the sun provides more than enough energy to overcome entropy on the Earth, making life on the Earth not a violation of the second law. But simply adding energy to a system doesn’t automatically cause reduced entropy. Solar energy alone does not decrease entropy; in fact, it increases entropy, speeding up the natural processes that cause breakdown, disorder, and disorganization on earth. If this were not so, then frequent sunburn would make you look younger and live longer.
The apparent decrease in entropy found in biological systems on the Earth requires two additional factors besides an open system and an available energy supply. These are: information to direct the growth in organized complexity, and a mechanism for storing and converting the incoming energy into something usable.
Each living organism’s DNA contains all the code (i.e. the program information) needed to direct the process of building the organism up from seed or cell to a fully functional, mature specimen, complete with all the necessary instructions for maintaining and repairing each of its complex, organized, and integrated component systems. This process continues throughout the life of the organism, essentially building-up and maintaining the organism’s physical structure faster than entropy can break it down (though entropy ultimately does prevail, as each organism eventually deteriorates and dies).
Living systems also have the second essential component—their own built-in mechanisms for effectively converting and storing the incoming energy. Plants use photosynthesis to convert the sun’s energy into usable, storable forms (e.g., proteins), animals use metabolism to further convert and use the stored energy from the plants they eat, and other animals eat those animals to use the stored energy their physical bodies contain.
While the “open system” argument can explain how already existent living organisms may grow and thrive, and it can explain the source of the energy needed to form organized protein chain molecules from random amino acids, it does not offer any solution to the question of how life could spontaneously begin this process in the absence of the program directions and energy conversion mechanisms described above, nor how a simple living organism might produce the additional new program directions and alternative energy conversion mechanisms required in order to produce the vast spectrum of biological variety and complexity observed on this planet.
In light of all of this, we can clearly see that the “open system” argument fails to adequately justify the violation of the second law that is seen in the development of specified and complex life on the Earth, and that a system can have randomly generated specificity, or it can have randomly generated complexity, but not both. Therefore, the premise that living organisms with specified complexity randomly and spontaneously developed within an entropic universe not only violates one of the most important laws of physics, but is so astronomically improbable that it takes more faith and feelings-based, biased, emotional conviction to justify this belief than a belief in a world designed by an intelligent entity existing outside of our “closed-system” universe. Therefore, the specified complexity of the natural world compels the rational person to infer an intelligent designing force guiding the formation of that world.
The burden of proof then falls on the person who is so biased that he or she denies the obvious rational conclusion in favor of the absurd improbability.
A logical case for the existence of God:
Scenario #1: A homicide detective is investigating a murder. He begins his search for the murderer at the end result of the action (i.e. the crime scene). He uses blood splatter evidence to trace the trajectory of the bullet. He finds the bullet and analyzes the firing pattern to determine the gun it was fired from, etc., working his way back to the murderer (watch any episode of CSI to see this in action).
Scenario #1: In this scenario, a major assumption that the homicide detective makes is the belief that every action has a cause that precedes it, and thus the series of events leading to the murder can be reconstructed and traced back to the originator of the crime, i.e., the first cause of the murder. Whether that is an affair, or money, or abuse as a child, whatever it is, there is the assumption that something (or some-things) happened. And that something(s) set in motion a chain of causal events that led ultimately to the resulting action, i.e. the murder.
This basic premise can be taken even further, because everything that exists in the universe can be traced down the chain of causality all the way to the beginning; one event causes another, which causes another, which causes another, ad infinitum. In other words, the whole universe is a vast, interlocking chain of things that come into existence because other things cause them to be. Our murderer would not be here to murder anyone without billions of causes, from the marriages of his parents and their parents all the way back through the development of the first protein molecule to the cooling of the galaxies and the Big Bang.
Everything that comes into existence must either exist by itself (i.e. by its own essence or nature), called an Independent Being, or it must exist because of something else (it was brought into existence/caused), called a Dependent Being. If it is an Independent Being and exists by its own essence/nature, then it’s being-ness is sufficient to explain its own existence, and it cannot have been created because that would mean it was caused to exist by something else, and thus it exists eternally. It cannot not have these qualities and still exist as an Independent Being, just as a triangle cannot not have three sides and still be a triangle.
If, on the other hand, something is a Dependent Being and exists not by its own essence, then it needs a cause, a reason outside itself for its existence. Dependent Beings cannot cause themselves. They are dependent on their causes. But does the universe as a whole have a cause? Is there a First Cause, an uncaused cause of the whole chain of causality in the universe? If not, then there is an infinite regress of causes, with no first link in the great cosmic chain. If so, then there is an eternal, necessary, independent, self-explanatory being with nothing above it, before it, or supporting it. It would have to explain itself as well as everything else, for if it needed something else as its explanation, its reason, its cause, then it would not be the first and uncaused cause. Such a being would have to be God. If we can prove there is such a First Cause, we will have proved there is a God.
Why must there be a First Cause? If, as previously mentioned, the universe contains only Dependent Beings, then the whole universe is unexplained without a First Cause. If there is no First Cause, each particular thing in the universe is explained in the short run by some other thing, but nothing is explained in the long run, and the universe as a whole is not explained. If there is no First Cause, then the universe is like a train moving without an engine. Each car's motion is explained proximately by the motion of the car in front of it: the caboose moves because the boxcar pulls it, the boxcar moves because the cattle car pulls it, etc. But if there is no engine to pull the first car and the whole train, the train cars cannot move of their own accord. The universe as a whole existing wholly independent of some First Cause is like a train moving without an engine.
Therefore, the universe must have a First Cause, and that cause must be an Independent Being. If there is no Independent Being, then the whole chain of causality in the whole of the universe is dependent on nothing and could not exist. But it does exist. Therefore there is a First Cause, that First Cause is itself uncaused and must then be an Independent Being, and this Independent Being is necessarily eternal and explained and justified wholly by its own being-ness, i.e. God.