(Steemed) If we should ever succeed in discovering life on other worlds, should that discovery trouble us?
I think most people would say the answer to that question is ‘yes’ only if said aliens have tremendous technological capability. If that is the case, they just might come over here and use their technological might to take our gold and steal our women. On the other hand, if those aliens are primitive, there would be no need to be overly concerned. Why should anybody worry if we discover microbial lifeforms inhabiting Europa, for example?
Actually there is a very good reason: The Great Filter.
The Great Filter is the hypothesis that there is some immensly challenging barrier standing in the way between the emergence of life and the establishment of an intergalactic civilization. Whenever life runs up against this barrier, it is extremely unlikely that it will overcome it. It either goes extinct or never develops to a point where its mark on the universe can be noticed, which probably amounts to extinction in the long run.
The Great Filter could lie in our future. Perhaps civilizations aquire technological might before they evolve the wisdom to use it wisely, and end up destroying themselves? Perhaps there is some stage in past evolution that is profoundly hard to reach. The development of the eukaryotic cell, for example.
But if we discover primitive life on other worlds, that would make it much more unlikely that the Great Filter does lie in the past. It is not much of a Great Filter if life has overcome it not just once, but twice and maybe many times.
If we find bacterial or- even worse- multicellular life, that should really worry us, because it makes it much less likely that the Great Filter is something we have successfully overcome.