Plateau Planets

Not everybody wins the lottery. Even if the lottery is rigged for lots of payoffs. Some planets that place their bets by being in the habitable zone of their star are not going to wind up with an alien civilization that flies around the galaxy starting colonies and generally being a big cheese. They are going to get stuck somewhere on their climb to the heights of planetary success. Let’s call them plateau planets. They get up to some plateau of development, along the developmental line laid out in another post, and then stay there or go back down. They never get past their plateau. There are always some losers.

If there is just one Great Filter, and it is a really effective one, stopping 90% or 99% of all planets from achieving the ultimate in planetary status, most planets are going to be on the same plateau. Wherever you go in the galaxy, assuming you are from one of the small percentage of winner planets, you are going to see planets on this plateau. Assume it was chlorophyll. That means that if you toured the galaxy, and there is certainly no reason to do it except for a thought exercise, you would keep seeing the same thing everywhere you went. One planet after another with chemotrophs. Chemotrophs here, chemotrophs there, everywhere a chemotroph. Your tour of the galaxy would be very boring. Every time you came out of hibernation to look at a planet, it would look pretty much the same. Land with nothing on it. Oceans are pretty empty, except near a source of chemical energy, such as an undersea volcano.

For convenience, call these the chlorophyll plateau planets. That means an observational program to find biosignatures, by which they mean oxygen, will find nothing. The whole galaxy would be filled with planets with life of a sort, and nothing would be detectable. Chemotrophs don’t leave any signature.

It also means that an early civilization in category 1 would have a field day. All they would have to do is to drop in some seeds for chlorophyll organisms, make sure they took hold, and come back after a long time to find a world much more to their liking. The entire galaxy would be waiting for them to come by and seed the habitable planets. If they persevered for a long time, and an alien civilization capable of migration could last virtually forever, they could finish off the galaxy and top it off by seeding planets of newly formed stars. What would this mean to our Earth-borne observational program? All the planets have oxygen and therefore chlorophyll. This causes a conflict with the results of Earth’s archeogenetics program, which finally got the funding it deserved and came up with some impressive results, namely that chlorophyll was a Great Filter, coming in at 99%. This could mean squabbling for a long time between scientists in different disciplines, or it could mean a realization that the history of the galaxy was one of initial colonization, not evolution. Evolution hits a Great Filter and colonization fixes it.

Suppose there were two Great Filters at 90% each. The same situation prevails. If both of them were remediable by seeding, for example with chlorophyll or with chemotroph carnivores, depending on which plateau the planet had become stuck on, the same observational results would be found.

Even three or four GF’s would lead to the same result, provided they were solvable by seeding, and almost all of them in batches from one to nine would be. What this means is that if life is possible in the galaxy, and one alien civilization of category 1 arises during the first billion years or so, all habitable planets with reasonable environments would have life. The life on all these planets would be the same as it would have arisen from the same seeds. Great Filters do not do the job that they were supposed to. They do not prevent a planet from having intelligent life and high-class starships; they facilitate the uniformity of civilization all over the galaxy.

Consider the other end of the spectrum. There are no Great Filters. Instead, there are bifurcations on the road to intelligent life. This means that there is no uniform path to advanced alien civilizations, but there are two or four or eight. A bifurcation into two lines of development does not mean anything about what will reach intelligent civilization, unless there is a feedback loop that promotes self-preservation and eliminates alternate pathways on the same planet. As an example, assume that asteroid Chicxulub never hit Earth, and dinosaurs never were pressured into becoming extinct. Evolutionary pressure being what it is, they may have evolved into tool-using hunters whose brains expanded. If this happened, mammals would not have had the opportunity they did as the dinosaurs with their earlier intelligence would have hunted them down, and we would have a civilization here with some differences, maybe with no hair and a strong preference for sun porches.

This spectrum we are talking about is the spectrum of the power of evolution to overcome difficult mutational boundaries and to provide advantages even across taxonomic classes, to say nothing of finer divisions. If we assume evolution has this effect, for those potential Great Filters that are amenable to evolution, which would be batches one through ten, there would be no plateau planets. Instead, there might be a diversity of life forms, where the one to arise first puts the others out of business. Higher batches of Great Filters arise during the ‘evolution’ of society, where evolution is not biological, but based on the accumulation of knowledge. A perhaps comical analogy would be that the earlier batches of Great Filters represent the hardware side of the development of intelligent life and advanced civilizations, and after that runs its course, the software side has to do its part. In this situation, we would find a variety of life with intelligence on different planets, perhaps most stopped on a common plateau, for example the Baconian Great Filter, where no one figures out how to get science started. Just like we can metaphorically think of biological evolution as having the power to overcome obstacles and leave all plateaus behind, we can likewise think of intelligence and accumulated knowledge as having the power to overcome later occurring obstacles and leave the higher plateaus behind.

If we think about the optimistic case where evolution and intelligence are both very powerful forces, we might then find a galaxy with a variety of intelligent creatures, provided they had not chosen to leave their original form behind and more to something else within the realm of asymptotic genetics. This means that in order to unlock the puzzle of life in the galaxy, the ‘where are the aliens’ question, we have first to decide if the overarching pattern is Great Filter, early colonization, or widespread bifurcations