I have serious doubts as to the existence of intelligent life being out there, that we can contact.

1) Earth is in the perfect orbital position to sustain life; not to hot or too cold. How many other planets will be this lucky.
2) Not all stars we see have planets.
3) Our existence can be numbered in 10,000 years, a very short period in universal terms.
4) The odds of another intelligent life existing in that same time as us within our vicinity is very remote.
5) The distances to be covered, unless the "Speed of Light" can be broken (which I doubt), makes contact very unlikely.

Therefore do I believe in Aliens. No.
Do I think they exist, maybe. I still await the proof.