Why do people think the Drake Equation automatically proves aliens exist (or are even likely). Over half the variables in the equations are impossible to determine or even estimate. We have no idea how rare abiogenesis is. So even if all other factors of the equation are absolutely enormous, the probability of life might still be so small humans are the only intelligent life to exist in our universe. It's easy to see how this is possible looking at permutations. A set of objects has n! permutation, and the shortest string of organic molecules that is sell replicating is likely thousands of units long. Since factorials grow absolutely massive very quickly, it's not unthinkable that Origin of Life only occurred once in the history of the universe and it was here on earth. I mean 61! is already 10^82, more than all the particles in observable Universe, and the simplest life is likely composed of even more molecular units than this. So why is everyone so convinced by this malarkey