Sorry for not being clear. I don't think it would necessarily shake people in their beliefs, just that the discovery of alien life would have a big impact on th

Sorry for not being clear. I don't think it would necessarily shake people in their beliefs, just that the discovery of alien life would have a big impact on theology, in a way that the theoretical idea that it probably exists can't. For instance right now people can debate about whether alien life would have original sin or not. Depending on your understanding of the Bible some people argue that original sin, and thus the tendency to sin and the necessity of Jesus is unique to Earth. If we meet aliens this wouldn't just be theoretical anymore, instead how the aliens acted could be used as evidence one way or the other.