Don't bother. He's just going to say that Drake's Equation is a fallacy like he's done the previous 200 times.
While there's no concrete proof, denying the possibility of intelligent life in the vastness of space is pretty, well, selfish. I don't believe that the human race is so blessed as to be the only intelligence (if you can call it that) in the universe. You can believe what you want, but I'm certain that we are definitely not alone.