Certainty

To those who say "Science changes all the time we need religion for certainty", I say: Yes science changes, but always toward more and better explanations and knowledge. Consider Newton and Einstein...
Before Newton we knew that the planets orbited in elliptical arcs around the sun, Newton didn't explain gravity or discover it, he worked out mathematically how to predict a planet’s orbit using the concept of gravity.
When Einstein came along, he explained gravity using the concept of warped space/time. He didn't prove Newton wrong, he just went one step further. Science never throws away what works, it just builds on earlier knowledge to get better and better