In naturalistic atheism, all that exists in the universe is “matter in motion”- even in the area of human “thought.”As a result, all free thought is lost in this system, because the thoughts produced by an individual are simply the result of an electro-chemical response due to internal and external stimuli (remember, everything is physical “matter in motion”). Hence, on the foundation of the naturalist worldview, the supporter of this position could never know if naturalism is true, and further, they are forced to say naturalism is true simply due to the electro-chemical response taking place in their brains and not due to evidences or freedom of thought (yet, they debate and try to convince people that their system is true, as if the person had the freedom to make up their own minds). The short video below by Dr. Greg L. Bahnsen explains this nicely.
The second video posted below is the entire Bahnsen vs. Stein debate. If you have never heard this debate, you must. Dr. Bahnsen utterly destroyed the atheistic worldview in this debate and it has become a classic in many Christian circles. It is a wonderful example of the irrationality of the atheistic position and serves as an equally wonderful example to show that without the Christian God, “you could not prove anything at all.”