DO ALIENS EXIST?
Simple mathematics says a resounding yes. The sheer number of stars and galaxies and galaxy clusters mean that there must be countless millions of planets capable of supporting life, and percentage of those capable of evolving advanced life. What we have found from human life on Earth is that a confluence of favorable events must take place for life to evolve for an extended period without an extinction event; for it to evolve in a so-called Goldilocks Zone (not too hot, not too cold); and in a certain gravity environment that allows for three-dimensional mobility and with particular functionality (the opposable thumb for example). So other life forms equal to our development level or beyond it are no doubt out there somewhere beyond the Earth.