Through:
1) Manipulation of science.
2) Promulgating it (Atheism).
It was once said that there is no evidence in the world capable of convincing an atheist of the existence of a God and in fact this is largely true, because the problem is not in the evidence but in the atheistic mentality, in the mental system that puts their principle being that there is no God, no Creator, and no occult (unseen matters). In this case the evidence is outside the scope of the debate in the first place.
Summary of what has been said: The atheist believes in materialist philosophy and then seeks to find justification in science and then claims - in front of people - that his atheism is based on science.