look, i have no intention of proving anything to you right now nor starting a debate with you (maybe tomorrow) but im still waiting to see a valid evidence from your side since you said that your friend "refused to accept any logical reason you gave him that God doesent exist". thats the only reason im still awake and im curious to see what you have...
Ah well, in that case I'll just use simple logic because it would take me forever to explain why I don't believe in God.
Christians (and other believers) believe God is omniscient and knows everything, including everything that has happened and will happen, as well as every thought your mind creates before you think it. If that's the case, there is no "free will."
They also believe God is omnipotent, and can do anything. Problem is, if God can do anything but doesn't lift a finger to stop all the disasters, massacres and wars that have happened, are happening now and will happen in the future, God is also a psychopath who enjoys watching our misery. However, if God is not omniscient or omnipotent... well, in that case God is not a "god" and doesn't exist
And the countless weaknesses of religious arguments, explanations, and apologetics...
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There is no evidence that God doesn't exist or that he does exist.
There are logical arguments on both side but I find none of them very convincing. Therefore, belief in God is merely a choice, you choose to believe or to disbelieve.
I was an atheist for a long time because I thought that there was no evidence of God's existence. However, I'm a Catholic once again because I choose to believe that God exists for other reasons.
Which is why I put the word evidence in quotation marks

However, it just seems easier to me not to believe in something other people say exists but can't see, hear or percieve through their 5 senses and the only reason they believe in it is because they were indoctrinated since they were kids or because God changed their lives when they were alcoholics.