Given the universe is infinite, and the fact that we are here, one could certainly ascertain that the rate of occurrence of life must be non zero. If there were intelligent sustained life anywhere near us(local to our solar system), capable of traversing the solar system, they most likely are intelligent enough to stay far away from us. That leaves the further reaches of the galaxy. What would a machine functioning solely off of logic do? Any life capable of traveling multiple light years absolutely has to have an extremely logical approach to things, or it would've perished already. Looking at humans; its just really difficult to foresee a non-logically functioning entity, that is not self aware, do anything other than destroy itself eventually, as well as whatever it comes into contact with.