I believe the chances are quite a bit larger than "1/2" for there being other life in the universe.
Well, you can feel free to believe whatever you wish, of course, I just prefer things like evidence and logic. We didn't really evolve to deal well with calculating probabilities (of all the areas of analytic, logical thinking probability is the one that is perhaps the one at which people are both least likely to have any kind of good intuition and most likely to have trouble learning). In this case we have a certain amount of data (a lot of data on evolutionary processes, complex systems, habitable zones, timelines required for complex life to evolve, etc.) and an approach to calculating "uncertainty" using a certain approach to, or kind of, "probability theory" called Bayesian inference/analysis/probability/statistics. It is ideal because we don't have any idea about the actual probability space that standard (elementary) probability theory requires, and that's why we find e.g., "Bayesian analysis of the astrobiological implications of life’s early emergence on Earth" in one of the leading science journals (PNAS). See
here.
I actually think that the chances of there not being other life out there is nearly 0%
For extremophiles, it's probably nearly 0. For complex life, there is no rational inference method that would give us reason to conclude that complex life is at all likely anywhere in the universe. The kind of inference that would lead us to such conclusions is of the same type that leads us to the conclusion that their must be a designer because we see design. In the first case, the reasoning is that because life arose here, and the universe is so vast, that means somehow it is likely life evolved elsewhere. In the second, we simply reverse the perspective and look at all the things that had to be just so for us to exist, and conclude that the probability for our existence is so tiny that the only way we could exist is due to a designer. Both perspectives err in that they take the starting premise (we/life exists) and "double dip": we assert that because we exist (our premise) certain things must follow because...well...we exist. There's no epistemic justification for taking the premise to the next step other than speculation without reason, grounds, evidence, logic, etc. But people are not inclined to think logically in general and certainly not when it comes to calculating probabilities.