What science are you talking about?
Astrophysics. I have never heard ANY astrophysicist say conclusively and unequivocally that we humans here on Earth are the only form of life in the universe. If this universe, with more galaxies in it then there are grains of sand on a beach and to think that if you were to scoop up a handful of that sand and see only one blue and white grain of sand, then you and anyone else is a moron.