The human brain helped us surviving. That's what natural selection is all about. If a mutation helps an organism to survive, the new genes will replace the old ones.

"Furthermore, it's not logical to say that the universe is infinite. Why? Because chances that a dominant species with faster-than-light-travel should have developed somewhere is not zero, thus it must exist. But I'm not a slave yet, so your argumentation leads me to the conclusion that the universe is not infinite."
Firt of all, there is evidence that the universe is indeed infinite. It could be curved like the Earth's surface, so we would return to the beginning after going in the same direction all the time, but it rather seems that it's pretty flat on larger scales.
Faster-than-light-travelling has a propability of 0%, because it's not possible. And alien species are so impropable that, if they exist, they couldn't detect us and reach us before both races are extinct, because if they are a million lightyears away, light needs a million light years to get there.