Evidence
The single greatest difference between a natural worldview and a supernatural worldview is the method of determining what is real. The supernatural world allows any and all objects of the imagination to be called real, so long as enough people claim to believe them. The natural worldview will only consider something to be real if it is evidence-based.
Science encourages the endless hunt for explanation while faith discourages discovery and prefers to answer all questions ‘God.’ The increase in our knowledge since the advent of the scientific method is exponential in comparison to the preceding 50,000-100,00 years when faith was in charge of the truth.
While science continues to seek for answers, its approach is incomparable and unstoppable. The difference between faith and evidence is as simple as this: if a meteor destroyed all life as we know it, and evolution started over from scratch, future potential beings that attained consciousness would inevitably come to discover that 2+2=4, that the earth revolve around the sun, that mind is a projection of the brain, etc. Jesus, however, and all other details of Christianity would be gone forever. If religion once again emerged as a tool, it would include entirely new gods and concepts of faith.