For the first time, astronomers have found a planet other than Earth that’s in the right temperature zone for liquid water.
Naturally, in the excitement, that leads one of the scientists interviewed for the story to make a stupid logic error that I have seen several other people make when discussing the possibility of extraterrestrial life:
But because conditions are ideal for liquid water, and because there always seems to be life on Earth where there is water, Vogt believes "that chances for life on this planet are 100 percent."
Now, we may indeed find in the future that on any planet with liquid water, the existence of life is almost certain. But so far, we have a sample of exactly one planet on which we know there is both liquid water and life. But just because water is a necessary condition for life (as we know it) to exist on our planet does not mean that the presence of water is a sufficient condition to assure the existence of life on another planet. There may be other factors necessary to life that are not present on this newly discovered planet.
Another similar mistake I see people make happens when some strange form of life is found to exist in extreme conditions. People tend to conclude that if life can survive in such extreme conditions here on Earth, then there is probably life in similarly extreme conditions on the moons of one of the gas giants in our solar system, or whatever other place such conditions are found.
Again, it’s possible we may find life under the ice of Europa or in the volcanoes of Io. But just because life can adapt to extreme conditions does not mean life can develop initially under those conditions.
Earth is far too small a sample from which to generalize with any certainty about the conditions in which life is likely to arise and exist.
(Fortunately, as a science fiction writer, I don’t need certainty; I just need plausibility.)