The universe has some sort of Order to it, which is why our sciences work. Physics seems fundamental to the natural science, studying physical phenomena. Mathematics seems fundamental to physics, studying abstract principles. Logic seems fundamental to mathematics, studying principles of Reason itself. This implies that Reason is fundamental to the universe, and some reasoning entity is responsible for the Order we see.
This reasoning entity would precede the universe and its Order, making it supernatural and non-physical, would know everything, be active everywhere, and could will anything to happen.
This is God.

I do not see how anyone can deny that God exists. It seems a wholly unreasonable position to me.
>inb4 God must be evil by my personal standards
Lol
Lmao