Given the billions of stars, the number of planets around them, and the length of time the universe existed, there is probably ample opportunity for life to emerge. Whether it is carbon-based, and what form of energy processing it does is subject to all kinds of speculation, but history teaches us that most of our "wild" guesses are too conservative and limited in imagination. If you are religious, then the arguement can be made that there is no reason why God would not want to populate all environments with living beings.
When we project the abilities and capabilities of alien life forms, we do so using the prism of our experience (very short), understanding (very poor), and our imagination (quite limited). Our knowledge of physical laws is relatively recent, and by all accounts, very incomplete - yes, we know what we know, but we are clueless of what we don't know we don't know. And in that lack of knowledge hides a lot of capability that can give other living entities abilities that would appear to be magical or impossible to us.
The other concern is that IF we came across another life form, how would we even know how to relate to it? We share this planet with various primates, and animals that exhibit intelligence, feeling, and culture, yet we persist in killing or torturing them. Our track record, as a species, does not appear to be conducive to respectful sharing of living space. So IF there are aliens out there that are sentinent and able to interact with us, why would they want to? We haven't yet learned how to play nice.