Why can't the great filter be multiple things?

@Guilhermesampaiodeoliveir It can be, see comments below.

Can't wait to see this one resolve 🔥👽

Simulation hypothesis: there is no great filter, we're just in containment and other intelligent life would be too complex or politically fraught to include in our sandbox.

Guys life on Earth started practically before the magma had even finished cooling, no way is that a great filter compared to the other precambrian stages

@TheAllMemeingEye perhaps life is physically possible on almost all celestial bodies. But the chance of molecules randomly assembling into a functioning, self-replicating nanomachine is simply unbelievably small.

@Jan53274 I was under the impression that the Drake Equation and Great Filter were built on the model that only terrestrial planets with liquid water are considered, otherwise we'd have to count the vast interstellar medium, and then difficulty of life emergence being the main filter becomes a no brainer

@TheAllMemeingEye The interstellar medium isnt accounted for because it is (as far as we know) very unfriendly to life as we know it, minus possibly a short time period after the big bang when CMB was just right for life to be possible everywhere. So as @Jan53274 said, it could be suitable almost everywhere but could be just extremely unlikely to start off, hence being the great filter.

What would it mean for the great filter not to exist?

@Khazar_Man_From_Turan For example, life evolves with no obstacles to intelligent civilisations, and there are a lot of them around us, but we do not see them for some reason.

Does the aspect of the Dark Forest Hypothesis where there are numerous extraterrestrial civilisations but they are hiding because they are afraid of destruction rather than actually getting destroyed resolve to the third party destruction Dark Forest Hypothesis option or the no filter option?

@TheAllMemeingEye No filter.

@IhorKendiukhov suggestion: edit the no filter option to mention the hiding dark forest and early grabby aliens scenarios in parentheses so people don't bet up the wrong option

What are the numerical requirements for a given stage to count as a great filter? Can multiple resolve yes? For example, we might find the habitable planets of the galaxy are 99% procaryotic equivalent, with the remainder 99% single cellular eukaryotic equivalent, with the further remainder 99% multicellular but non-complex brainless life. In this case, do all 3 resolve yes, or do they resolve to equally split percentage, or does only the first one resolve yes, or do none of them because no single one was sufficient alone etc?

@TheAllMemeingEye Multiple can resolve yes. If there are several options that significantly “filter” biospheres, all of them will be considered filters. I would refrain for now from giving specific percentages, but it looks like 99% is a lower bound on the percentage that qualifies as the definition of the Great Filter. In ambiguous cases, I will resort to the best judgement of exobiologists (or similar relevant experts) available to me.

@IhorKendiukhov this is a tangent but I've been wondering it for ages, is exobiology considered a subset focusing on the biological aspects of a larger field about extraterrestrial civilisations in general (perhaps called exology?), or is that larger field still called exobiology even when discussing the potential political systems and technology of such civilisations?

@TheAllMemeingEye I think as of now it is rather the second alternative.

@TheAllMemeingEye makes a lot more sense for that term to only refer to the biological aspects

@robm yeah that's what I was getting at, though what would you say is the correct blanket term for the speculative biology, technology, politics, culture etc? Is it exology (made up off the top of my head)?