There does come a point, however, that even science fails to show absolute proof... For example, although there is a lot of evidence supporting the Big Bang Theory, since no one was there to witness the event nor is it possible to recreate it (to its full extent), it will always remain a theory.
Actually there is enough evidence that the BB did happen via background microwave radiation expanding from a center point. Just because humans didn't exist when it happened does not necessarily mean we can't know it to be fact. We don't know precisely how it happened (as in we don't know what every little particle did), but we do know it happened due to the evidences that are readily available. The same could be said for dinosaur extinction, climate change, etc. etc. There is a difference from a theory and a scientific/practiced theory.
That was actually what I was talking about, scientific theory... Like I said, although there is a lot of evidence that supports the theory (like the background radiation that you mentioned), because there is no way to reproduce it, it will always remain a theory, not a scientific law of nature.
I should mention that I picked up these ideas after reading a book for a college ethical science course. I couldn't quite remember the name of the book nor the author, but I think I've found him now after Googling more about what I remember of his life history: see http://en.wikipedia.org/wiki/John_Polkinghorne. Rev. Dr. John Polkinghorne was actually a professor of theoretical physics at Cambridge that later became an Anglican priest.
Looks interesting! Yeah I don't want to come off as some nihilist-atheist type of person. I classify myself as an agnostic-atheist or a "Sure there could be a god or gods out there, but w/o basic proofs, you cannot state anything as truth" type of person. What type of position do you hold? You're catholic yet you speak like an agnostic-theist. I'm just curious to know.
I am a Catholic although there are a few things that I do disagree with the church about (eg women not allowed in the priesthood, priests not being allowed to marry, homosexuality as a sin, etc.). However I also am a scientist by education and so I've really looked into this issue of the relationship between religion and science (hence why I took that course to begin with). Also being involved in the sciences, many of my friends are more along the lines of your beliefs if not completely atheist. And in talking with them about my faith, I've found that many have misconceived notions about Catholicism esp. when considering what other Christians believe (again why I said that "Christians" are often painted with a broad brush) as well as the church's history including its response to other scientists in history.