The fact that you're here is proof of God. 1. If you believe in God and God does exist, you will be rewarded with eternal life in heaven: thus an infinite gain. 2. If you do not believe in God and God does exist, you will be condemned to remain in hell forever: thus an infinite loss. 3. If you believe in God and God does not exist, you will not be rewarded: thus an insignificant loss. 4. If you do not believe in God and God does not exist, you will not be rewarded, but you have lived your own life: thus an insignificant gain. Therefore, it's simple logic to believe in God.