Dear 100 Hour Board,
Similar to my last question, what would be the effect on the world if God and religion were proven to not exist? The big bang and creation is fully understood, spiritual feelings are 100% explained by brain science and can be measured and artificially reproduced, previous miracles are proven to be advanced science from alien visitors, whatever combination explains it, we're sure it's just the physical world, there is no spiritual plane. How does society move on from there?
Again, I'm not interested in the "no one can prove the non-existence of something" arguments, unless it's in the context of the small minority of flat-earth anti-vax types who will continue to deny the truth in the face of overwhelming evidence.
One of my pet peeves are hypothetical situations that have a zero probability of ever happening. I don't really know why, but it just bugs me. This personal annoyance probably has something to do with vacuous truths. It is perfectly logically correct to state that if the sun was a giant peach, then humans would have the ability to shed their skins like snakes. If something can never happen, then everything else has an equal probability of occurring with it. So, I would be correct in saying that in your hypothetical, the effect on the world would be to turn it to green Jell-O.
For the sake of your question, I suppose I'll step off my curmudgeonly soapbox, and shift your hypothetical to one that is actually tenable (thus appeasing my qualms).
As you are aware, it is logically impossible to prove God does not exist. No matter how advanced science becomes, and even if there was genuinely not a supreme being, we could never squash the possibility of a supreme being. And this argument cannot ever be lumped in with "flat-earth and anit-vax types" because those people's positions and world views CAN be disproven--the view that God could exist IS the overwhelming truth.
I also dislike the viewpoint that science and religion are diametrically opposed. Greater knowledge and understanding of how things work is not what draws people away from God. Science is not a replacement for God, and I truly hate it when it is perceived that way (by either a deeply religious person or scientist).
Finally, your scenario is predicated on the assumption that people are rational beings. We are not. How people form their world views and life perspective is not through a series of logical proofs. Instead, what we believe is largely shaped by our personal experiences and surrounding culture.
Religion cannot be exterminated through rational arguments. However, it could be ended through changing human culture. Instead of being disproven, it's far more probable for religion to become culturally unpopular/out of fashion. It's kind of like how no one believes in Zeus, and the rest of the Greek pantheon anymore--it's not that any logician ever came up with a proof that the pantheon doesn't, and never did exist, but that culture has shifted over time.
If such a cultural shift were to occur, resulting in the discrediting of all religion to the public eye, I imagine that the day-to-day trappings of life would largely remain the same. People would still act in accordance with moral systems, and probably behave in the same manner.
This one's harder, I think. There are far more people that I think would reject this proof. Heck, even I might choose to reject it.
Human societies are built based on moral orders and moral codes. Regardless of whether those morals are based in a specific religion or not, people need purpose and rules or everything descends pretty quickly into chaos. So, if a society's moral code is already largely secular, they'll just shrug and say "yeah, this isn't news to us." So things won't really change for them. Meanwhile, in societies whose moral codes are very heavily founded in religion (you know, like the United States, for example) would possibly experience a bit more chaos as people tried to figure out where they stood.
Faith is what gets a lot of people through hard times, and I think that without that faith in something bigger, life could become a lot more bleak. Human beings need meaning in their life. So, while God and religion might not be the moral code at the end of whatever mess is created, something would become our new religion. It can be family, friends, nature, or it can be money, power, drugs, fame, sex... you whatever else.
I certainly don't think it would be a doomsday. I don't even think the laws would change that much, or that our lives would look much different. That being said, there is a strong potential that without belief in a higher power, judgment, or the afterlife, I would imagine that some people might disregard consequences and crime rates could possibly increase for a while... and perhaps suicide rates could increase... but eventually I think society would settle into its secularism. It is likely that more people would choose to reject the proof in favor of feeling like there was something more to their life. Turns out being a nihilist is actually pretty glum. Perhaps those people would be a bit mocked by the larger society, but it's not like people don't already do that to religious others.
In any case, I must honestly say that I think I would probably choose to modify my beliefs, but I don't think, honestly, that I would ever be able to let go of a belief in something bigger than myself... some kind of organizing power. Maybe I would come to understand 'God' to mean something else... not a personage, but a unifying energy. Anyway... I really don't think I would fully accept the scientific explanation. It sounds too... bland? too... meaningless? Not for me. I like being happy, even if, in your AU, that makes me naive.
The summer before my senior year of high school, I was selected by my local Rotary Club to spend a week with other teenagers at a summer camp learning leadership skills. It was called RYLA (Rotary Youth Leader Awards) and the purpose was to teach leadership skills and foster community awareness. One of the ways they sought to do so was in building self-confidence and a sense of self-worth. Growing up Mormon, I had a sense of self-worth pretty deeply ingrained, and in a lot of the sessions I got the impression that RYLA was like going to church but without the religious imagery. The facilitators were trying to instill happiness and confidence, teach us to care about our community and our fellow men, and give us the skills needed to inspire others to do the same.
I don't think any amount of evidence would convince people that there isn't some higher power in the universe, some universal sense of right and wrong. So while organized religion may dwindle, with fewer people reading the scriptures or attending church, I don't think too much in everyday life would change. People would still seek morality, and people would still try to help and uplift one another, because that's a deeply ingrained behavior in human beings.
Some things would change drastically, like interest in philosophy, but I think most people wouldn't alter their behavior too much.
The existentialisms of Jean-Paul Sartre, Friedrich Nietzsche, Albert Camus, and Simone de Beauvoir would become even more relevant than they already are. Life gets easier in some ways (e.g., prejudice can no longer hide behind theology) and more difficult in other ways (e.g., increased death anxiety). Everyone converts to Harry Potter and the Sacred Text and Vanessa becomes the new pope.