And now I will correct you.
A theory is a group of ideas meant to explain a certain topic, such as a single or collection of fact(s), event(s), or phenomen(a)(on). Typically, a theory is developed through the use of contemplative and rational forms of abstract and generalized thinking. Furthermore, a theory is often based on general principles that are independent of the thing being explained.
A scientific theory is a well-substantiated explanation of some aspect of the natural world that is acquired through the scientific method, and repeatedly confirmed through observation and experimentation.
There is a difference. And since there is no scientific proof to back the belief that there is no God(s), you cannot claim that atheism is backed by facts.
That's what's called an unfalsifiable hypothesis.
You can't prove there's no god, because any gap in the god hypothesis can be explained away. However, there's no evidence supporting the god hypothesis. And in science, the burden of proof is firmly on the person making a claim.
Honestly, this is such an old and tired argument that it's almost pointless to try to explain it again. I'll simply say that making a claim, and then saying it might be true because the other person can't prove that it's not, is not how science works. It's up to you, the person claiming the existence of something, to prove that it is so. If you don't like it, that's tough, but that's how it works. If you think it's unfair, then maybe so, but that's how it works, and has worked well for centuries. It's how we advance our knowledge of how the world actually works.
It's entirely possible that, because of this, there are things we don't know that we would've known otherwise. But we have also weeded out countless ideas that might otherwise have flourished, to our detriment.
I will say, though, that contrary to popular opinion, it's actually possible to prove a negative. The god hypothesis is largely immune to this, by its very definition, because any and all gaps can be explained away. I mean, that recent film, God's not Dead
, tries to solve the problem of Evil by saying god will get around to fixing evil ... some day. It's a complete cop-out, but it can
make sense. Because we're dealing with god, and anything
can make sense.
And that's why you don't start with your assumptions and make them fit with reality.
Here's a thought experiment I'm quite fond of. Imagine we lived in a world with no church, no bible, nothing of the sort. Is it even remotely possible that people would end up with a belief even vaguely similar to any of our major religions? I mean, sure, it's possible, purely by chance. But considering how many religions exist, and how different they are, what are the odds? Sure, they'd end up believing in something, as people are wont to do when they have no better explanation. But Christianity? Islam? There's not a snowball's chance in hell they would.