Carl Sagan on The cosmological argument
Sagan argued that the cosmological argument answers nothing — if God made the universe, what made God?
Sagan addressed the cosmological argument directly in Cosmos and in various lectures, always returning to the same objection: the argument is a non-explanation. If we say God created the universe, we must ask what created God. If we say God is eternal and needs no creator, we could say the same about the universe and save a step.
He was careful to distinguish between scientific humility and theological certainty. Science says 'we don't know yet' about the origin of the universe and actively investigates the question. Theology says 'God did it' and stops investigating. Sagan preferred the honest uncertainty of science to the false certainty of theology.
Sagan also challenged the assumption that the universe's existence requires explanation in the first place. It may be that the universe simply is — a brute fact that needs no more explanation than God's existence supposedly needs on the theistic view.
“If we say that God has always existed, why not save a step and conclude that the universe has always existed?”