Plenty of so-called experts will tell you that alien life does not exist. They will assure you that the almost infinite reaches of the universe, while beautiful and often at or beyond our threshold of understanding, do not hold any life other than that of the small blue-green globe that we call Earth.
These people are fools.
The reason that these people are fools is quite simple. They are unscientific yet purport to use scientific methods. They call parapsychologists quacks and charletins while attempting to foister their own opinions on others without real scientific evidence.
Consider the case of a genuine scientist - astrophysicist Stephen Hawking. He actually is happy to admit that aliens are out there based not on some subconscious fear of the unknown, but on statistical probability.
Here then, is the opinion of someone that we can trust. His opinion is not based on some arrogant assertion of the 'uniqueness' or 'special-ness' of planet Earth, but on good, sound reasoning. In the absence of definitive proof, reason is the best we have and the item most obviously lacking in the skeptics argument.
As he points out, the universe is made up of some 100 billion galaxies each containing hundreds of millions of stars. Now at this point, you could go and do some research in an attempt to verify this. I guess I am happy to take this particular astrophysicist's word for it.
Now assuming the U.S. definition of a 'billion' which is only 1000 million, and that when he says a galaxy contains hundreds of millions of stars he means literally only 100 million and not 200 million etc, well, I get the following calculation:
1 billion = 1,000,000 * 1000 = 1,000,000,000
100 billion = 1,000,000,000 * 100 = 100 000 000 000
100 billion * 100 million stars (assuming that's not 200 million in reality etc) = 10 000 000 000 000 000 000
Now assuming that our superior skeptic scientists could put one second's worth of analysis into each star to determine whether or not it holds life, then it would take approximately 316,231,532,078 years - which is over 3,162,315,320 centuries, to check them all.
In other words, at one second per star - which is naturally insufficient in reality to determine if they hold life - it would still take over 3 billion centuries to go through all of them.
So when an 'expert' tells you that there is no life in space, you might like to ask them how long they've been looking - if indeed they have.
Real scientists with real brains just cannot back them up.