One of my frustrations is that people very often will say that, “You cannot prove that God does not exist.” This is said without an examination of the conceptions of God being considered or the nature of what is reasonable proof. This problem derives in many cases from the distinction between logical proofs and physical proofs.
Logical proofs properly used are very powerful. We can start with the axioms and postulates of geometry and prove propositions based on those starting principles. A vast variety of useful understandings can be logically derived from the solid foundations upon which geometry is based.
Physical proofs are different. Scientists can disprove the existence of a supposed God who created the universe less than 10,000 years ago. A scientist can do this in a great many ways, by demonstrating that light from a distant galaxy is billions of years old or that the Grand Canyon is over five million years old or that a dinosaur fossil is 65 million years old. There are literally thousands of threads of evidence in cosmology, geology, biology and archeology which disconfirms the God of young earth creationism. We have physical proof that our universe is over 14 billion years old and the Earth is about 4.5 billion years old.
The problem occurs when Christians insist on using logical proof as the criterion. To illustrate, Christians who believe in the young earth creation notion dismiss the physical evidence by saying that God put that evidence there to test our faith. They have a hypothesis that is then logically consistent with the evidence.
For some reason people do not understand how preposterous this is. If someone is free to spin any hypothetical that they might wish then it is not possible to prove to proven anything about the world whatsoever Are you logically certain that you exist? Are you certain that you were born and had years of life?
Perhaps everything that we know and experience is just an emulation run on a super computer run by a very intelligent alien race. Perhaps that race is amused at how certain their emulated humans are that they are actually alive. They can in fact stop the emulation at any point. The emulated humans will have the memories of different experiences in their past and the paused emulation will still contain the feeling that time is flowing when it really is not. The emulation has been paused.
There is nothing in this hypothetical assumption that is inconsistent with your current life and experience. Given the fact that you cannot logically disprove this hypothesis you cannot be logically certain that you exist or that time is actually flowing as you imagine. Logical proofs about the real world are so profoundly weak that nobody can ever use them to prove anything about the real world.
Beyond that if God were an infinitely powerful being who provided us with messages in the Bible and other messages in the physical evidence we are then left in a quandary. What is the criterion by which we decide which message is right? Christian's just assume that the Bible is correct. We should be asking them how they know that the messages left by God in the physical evidence is not the one that God wishes us to accept as true.