Dante1214 wrote...
There was a formula developed at some point to produce a probability of life existing in a given area of space, but I don't remember what it's called.
That would be the Drake Equation. It has a pretty high error bar since it includes about 10 variables and only the first one is widely accepted while the level of acceptance drops at every subsequent point. It's designed as more of a "Look, these numbers are not favourable and still produce hope for life" than an airtight method of proving life in the universe.
Considering that there are about 400 billion (with a b) stars in the Milky Way alone and that it isn't an astoundingly large galaxy (despite being 100,000 light years across) it makes a pretty good case for the inevitability argument but it also puts into perspective how difficult it would be to discover. If life isn't in the Milky Way or one of our neighbouring galaxies we'll probably never come into contact with it.