There is no possibility of there being any other planets without life... the question is, how many of them are capable of supporting the kind of life that is intelligent and driven by thought, e.g. with a brain able to comprehend, process, and make conclusions on its own, instead of driven merely by instinctive urges to migrate and reproduce.
The life that we have here on Earth is unique. There's a very little chance that a species like us is out there anywhere, because for such a thing to happen would require a solar system to have the exact same size star, with the exact same number of planets consisting of the exact same properties as the one in this system. However, life can still evolve into an intelligent form even if the gravity is a bit lighter or the temperature is a bit hotter, etc. Obviously the species would have different traits than our own, depending on how their ancestors interpreted their purpose on that planet.
Human ancestors started making tools and using those tools to interact with the world and to survive in it, and found out those tools made it easier to live. Tools that killed game, tools that prepared them to be cooked, tools that made fire, tools that protected from invaders, etc... So, we evolved into a species that heavily relies on interaction with tools to live.
In the same way we evolved then, another planet which may have stronger gravity at the surface could contain a species that is evolving into what we would consider super strong beings, since they would have to develop ways to get around in, say, 10x earth's gravity, they would be much stronger when under earth's gravity than under their own. They might grow up with slightly more limited intelligence than our own due to having to spend so many generations working on just getting around in such gravity, but the idea I'm trying to get across is hopefully clear.
In short, I think there is intelligent life out there, or intelligent life is forming out there, just in different forms than we may be used to.