"The Fermi paradox or Fermi's paradox, named after physicist Enrico Fermi, is the apparent contradiction between the lack of evidence and high probability estimates, e.g. those given by the Drake equation, for the existence of extraterrestrial civilizations". I have always failed to understand how an accurate mathematical model is possible in a situation such as Fermis Paradox, where there is no baseline for comparison, as life has only ever been detected on this planet, Earth. If we have not discovered life elsewhere, how is it possible to determine how abundant or scarce life is in the cosmos? And also, even if you forget about this fact, wouldn't the sheer size of the universe as a whole vs the amount of space we have actually observed/explored be enough to deduce that we have not explored nowhere near enough space to confidently say no life exists outside of earth? "Would you conclude that no life existed in the oceans, by scooping up a single glassful of water?." This analogy really put it in perspective for me, and the math does in fact work out to reveal that the ratio of 1 glass of water to all of earths oceans, is infact more than the ratio of the volume of space explored by humanity to the entire universe.