I tend to believe that there is
life on other planets. Whether or not it is intelligent is another thing. A few things influenced me to believe
what I believe.
There was a line in the movie Contact. It was something like, "If there isn't life on other planets, then it's an awful waste of space." The direct quote is irrelevant, but the meaning is important. Our civilization is once again proving to be arrogant. Why do we instantly assume that we are the only life in the galaxy. It is similar to the Middle Ages when Earth was the center of the Universe, the Sun rotated around the Earth, and the world was flat.
The Drake Equation has somewhat influenced me. It's not perfect, since it is based primarily on guesses. However, the variables are based on conservative educated guesses. Even so, that leaves a whole lot of life on other planets.
Finally, why can't there be life on other planets. I know, it's a weak argument. It's easily countered, but what can I say. It just seems like there should be life on other planets. This ties into my first argument. Life can't be as rare as everyone thinks. Every single scientific advancement since the dark ages has pointed towards our arrogant conservative opinions about space being wrong.