It always amazes me to hear people say that science proves God does not exist. What a silly idea! Science can only observe material things. It has nothing to say about non-material things: love, integrity, beauty, mercy. They can't be measured in the lab.
It’s a good question, but I think there are pretty simple answers. You can find them in a 1936 movie called The Story of Louis Pasteur. At the time, doctors had no idea of the relationship between germs and disease. Three out of every ten mothers died of childbed fever as their doctors used unsterile instruments and failed to wash their hands. They passed disease from one infected mother to another and killed many. Louis Pasteur wasn’t a medical doctor. He was a chemist, but he was a brilliant diagnostician who realized how a few simple practices could save lives. For that he was ridiculed and vilified. Think about it. We’re talking about the mid 19th century, fewer than 200 years ago. Many doctors were arrogant ignoramuses who thought they knew everything. Some things never change.