me personally, i would not dismiss the possibility of other life existing here, or anywhere else.
you guys remember when the scientists were saying the prehistoric fish, the colecanth? that they was extinct millions of years ago but was found recently off the coast of madagascar? for years people believed what the schientists said till they had to retract what they thought was "fact".
if we are still hunting down and finding new plants and animals on our own planet. with that said, there is no way for me to doubt the possibility of life elswhere. by "scientists" own admissions, this planet, compared to other parts of the universe, is basically a baby still. so who's to say that there arent other life forms that are possibly(i'll keep saying possibly) millions of years more advanced as far as technology is concerned.