Mormons believe their god was once a man and was 'exalted' through what they call 'eternal progression' into a god. They claim that by being a good Mormon, popping out a bunch of Mormonlings, tithing to the church, not asking any hard questions, wearing your magic underwear, and, I don't know, fucking a magic hat or something, you too can become a god!

My wife is an ex-Mormon, she explains it better.

In relativity, the surface of the earth kind of is being accelerated upwards. It's not flat, it's spherical, but if put in a box with no way to observe outside, there is no test that can prove you're not being accelerated upwards. This is because there actually isn't a real difference. There could be elastic strings. In fact, certain unproven theories (that could supercede relativity and the standard model) imagines all fundamental forces, including gravity, as strings.

The biggest thing is that many versions of religion make claims that consistently contradict observable reality. A ton of people have religious ideas that have already been contradicted by science, while many more have ideas that can be proven wrong as science progresses. Some people do have religious ideas that might never be proven wrong in principle, but the biggest reason they can't be falsified is because they don't say anything about our material reality that can't be said with simpler theories. Basically, if the idea has no consequence on what exists in this world, why should we use it to guide our beliefs?

There are a countless number of ideas about what Gods outside our universe might want us to do. Just as easily as a Christian God might exist that takes copies of our mind and puts us in eternal heaven after death if we display Christian virtues in life, a God might exist that rewards only the cruelest and most murderous people with heaven. It might be that the worst people are rewarded by God and the best people punished. Should we murder others and never show kindness to other people if the God that can give us eternal life wants us to? According to people that justify their morals with God and heaven, we must.

As someone that most religious fundamentalists would burn at the stake, this is not a hypothetical. The religious right often thinks justice and fairness is a vice, while God demands his believers destroy the unnatural. If you only look at what they advocate, you'd think they worship the evil, anti-Christian God I came up with. Yet they claim Christ wants them to prevent me from living. Ethics cannot be reasonably justified on the basis of religion. We must look elsewhere to discover what is right and wrong.

Well, if something can be demonstrably true or false, then we can get concrete answers. Gravity is proven. There is no evidece--so far-- of tiny organisms controlling matter. Religion, on the other hand, could not be falsified in the scientific sense. Many religious claims have been disproven or could not even be proven. Unless you're a Mormon, we all know Jesus didn't come to America. There is no evidence of Red Sea parting according to archaeological studies. Someone claiming to seeing ghost right now, how can that even be proven or disproven? Edit: actually, Brian Cox made a great point that since we created a machine that could detect particles that is billionth of a size smaller, we still have not detected any signs of ghostly presence. It's a convincing point and to me, it sounds like he did debunk ghosts.

I have zero interest in truth. Science is about shutting up, calculating, and model building. If demons making things fall better explained the data of gravity that would be the model, but as of right this moment a demon based model is a poor one.