Argument from the Improbability of LifeThe next argument we will look at is a favorite of the creationists (in all their species: "young earth", "old earth" and "intelligent design" creationists) because it makes a pretence of being a scientific argument for the existence of God. There are many variations to this arguments, but they all boil down to showing the improbability of life (or anything else) as we know it. An example of this sort of argument is given by the French biophysicist Pierre Lecomte du Nouy (d. 1947) in his book Human Destiny (1947). In it he calculated that the chances of known molecules of protein simply coming together by chance is negligible. He concluded that the whole lifespan of the universe is not sufficient to allow the random collisions of atoms to form even a single protein molecule. But we see so many types of these improbable protein molecules in existence today, the only agency that could account for this is God.
In his article Judo Arguments (1975), the eminent science writer Isaac Asimov (1920-1992) showed how this kind of arguments are flawed. He took as an example, the much simpler molecule H2O or water. It consist of two Hydrogen atoms and one Oxygen atoms. Suppose we were to mix atoms of oxygen and hydrogen together experimentally. There are eight possibilities of how they could bond in tri-atomic form (we are ignoring, for the sake of simplicity, other forms of combinations): OOO, OOH, OHO, HOO, OHH, HOH, HHO, HHH. The chances of one picking the right water molecule, HOH, is 1 in 8 or 1/8. The chances of picking the correct molecule twenty times in a row is 1/8 to the power of 20 is 1018 (that is the number one followed by eighteen zeros!). One would conclude, with impeccable mathematics, that it would be an extremely improbable event to get water out of atoms of hydrogen and oxygen. But this is not what actually happens! In fact, if we were to mix atoms of hydrogen and oxygen together, the end result is not a mixed bag of various types of molecules but, almost without exceptions, the resultant molecules will be HOH. The reason is simple; atoms and molecules do not combine randomly. They combine according to the well defined laws of chemistry and quantum physics. Hence the probability we have presented, although mathematically impeccable, is wrong.
Herein lies the main flaw in du Nouy's reasoning, he assumed that the formation of a protein molecule can only happen by random collisions of molecules. But protein molecules does not form, all at once, as it were, from a sea of simple molecules; they are formed by a series of well defined steps. Proteins are made of peptides, which in turn are made up of amino acids which, in its turn are derived form organic acids. 
In fact since the early fifties many experiments have been performed, mimicking what is thought to be the primordial earth atmosphere and the oceans. All these experiments show that without any intervention, save the ultra violet rays (a reasonable assumption, given the absence of ozone - a byproduct of life - in the early atmosphere) and some electric sparks to simulate lightning bolts. Using this methods the scientists have discovered that amino acids, peptides and even protein molecules could be made, and abundantly. 
Thus arguments from the improbability of events such as the above almost always fail for the above reason: the believer has ignored the constraints in which the whole system must function.
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