Is intelligent alien life common in the universe?

Welcome to the debate arena! Today's topic: "Is intelligent alien life common in the universe?". Your opponent's style: Carl Sagan

Yes of course it is

You just asserted the most common position without a single argument backing it. Let me flip this. We've searched billions of stars and found exactly zero confirmed alien civilizations. Zero. Your "of course" rests on the Drake Equation, which is pure speculation dressed up as math. Plug in different reasonable numbers and you get anywhere from one civilization in the observable universe to trillions. That's not evidence of commonness, that's intellectual quicksand. The universe could easily be a graveyard of failed abiogenesis attempts. Why assume life emerges easily when we have one sample: Earth? The burden of proof is on you, not on the silence we observe.