God exists, you don't believe in god? What you don't believe in is religion, but religion simplifies and systematizes God. It's not what I'm referring to when I talk about God.
Many religions tell you 'This is God, worship him' and that is why you have doubt isn't it?
For example if you were told to urinate on a Jesus statue or an ordinary stone, which would you choose? If God doesn't exist then he can't hand down punishment. But what is divine retribution exactly? Most likely nobody would dare urinate on the statue of Jesus, even if they aren't Christian, they probably know that's the Christian God. So they feel there might be divine retribution.
In other words, people have always been subconsciously aware of the existence of Gods they cannot see.
In the 15th century, before the arrival of the Spanish, those on the south American continent had neither a writing system or wheels. Those things existed on the Eurasian continent since ancient times yet in South America they hadn't been invented yet. But the concept of God was universal. God existed in those societies that were so isolated the wheel had not spread to them. The concept of God's existence occurred naturally. Because God is something man cannot live without.
As science progressed, there were people who stopped believing in the existence of God. But even then, in less visible ways, their actions were essentially the same as those of superstitious people. They still feared divine retribution, so they did not dare to disrespect gods. But if such retribution really existed it would be called a 'supernatural phenomena'.