I just want to ask what is Quantum Mechanics? Why do atheists say that this is the biggest threat to the existence of God?
It just so happens that my specialty as as PhD scientist is in chemical physics, with emphasis in quantum mechanics. Now, you have given me a nearly impossible task. I need to define and explain quantum mechanics to a non-scientist in a few sentences. Hmmmm…..
Well, let me get around this as much as I can. Quantum mechanics is a branch of physics which is needed to explain the properties of matter on the extremely microscopic level. For things as small as electrons, the behavior observed is not predicted well using the "classical mechanics" of Isaac Newton. Light, "classically" is a wave, yet, in 1905 Albert Einsten showed that light is made up of particles–that light is "quantized." In the 1920s De Broglie showed that electrons, which are particles, act like waves. Sorry if the meaning and implication of this is not clear to you. This led to the uncertaintly principle and describing the atom using wave equations. After the 1920s, physicists concluded that we can only describe the atom in terms of probabiliby. The location of a particle is never certain. This is known as the "uncertainty principle." I am grossly simplifying here.
The bottom line is that with the success of Quantum Mechanics, physicists concluded that a completely deterministic view of the universe cannot work. There are purely random events which can only be predicted in terms of probability rather than deterministic Newtonian equations.
Phew! Now, what does this have to do with atheism, religion, philosophy and other brances of human investigation? People have tried to use quantum mechanics, both to prove the existence of God and to disprove God. I would say that both are on very thin ice. Those trying to use QM to prove God point out that a deterministic world view is inconsistent with science. Therefore a random design argument is invalid.
Then there is the other side. Atheists are, naturally, uncomfortable with the big bang. The fact that the universe appears to have been created implies a creator for most people. Atheists are clearly not prepared to accept this. So, they jump on quantum mechanics to solve their problem. The describe the creation of the universe as a quantum event. The creation of something out of nothing, they would say, is part of QM. By the way, just so you know, this is not the case at all, but never mind that.
To be honest, I would have to see the argument you are referring to. Although I have seen QM used to defend atheism, I have never seen it used as a sort of supposed slam dunk argument against God. I am sure that this is a bogus claim. On balance, I do not feel the existence of QM is strong proof either for or against God, but that it is a stronger pro argument for God than con. However, I cannot respond to the claim you apparently ran into unless I can see the nature of the claim. If you simply read someone saying "QM is the biggest threat to the existence of God" without an argument to support the statement, I believe you can simply ignore this as a useless/meaningless statement. Without support it is not even an argument.
John Oakes, PhD