One doesn’t need much in the way of definitions here to see the problem. The essential problem is that we don’t see anything out there that all shows a sign of intelligence. No major stellar engineering, etc. The fact that intelligent life and life may have fuzzy borders doesn’t enter into that arrangement much. If you want to to really be careful, you can talk about a version of the Filter that applies to life similar to our own. For our purposes, that’s about as worrisome.
you can talk about a version of the Filter that applies to life similar to our own
You can, but it’s pointless, unless you think that “life similar to our own” has a significant chance of arising independently of ours. The argument “we are here, so it stand to reason that someone like us would evolve elsewhere” is the generalization from one example (and also a failure of imagination) that I am so dubious about. I see no reason to believe that even given a more or less exact replica of the Solar system (or a billion of such replicas scattered around the Galaxy or the Universe) there will arise even a single instance of what we would recognize as intelligence. This may change if we ever find some non-Earth-originated lifeform. (Go, Curiosity!) Until then, the notion of the Great Filter is just some idle chat.
The argument “we are here, so it stand to reason that someone like us would evolve elsewhere” is the generalization from one example (and also a failure of imagination) that I am so dubious about
So in a nutshell in the framework of standard discussions about Fermi issues and the Filter one would just say that one heavy filtration step is that intelligent life as we know it seems unlikely to arise.
One doesn’t need much in the way of definitions here to see the problem. The essential problem is that we don’t see anything out there that all shows a sign of intelligence. No major stellar engineering, etc. The fact that intelligent life and life may have fuzzy borders doesn’t enter into that arrangement much. If you want to to really be careful, you can talk about a version of the Filter that applies to life similar to our own. For our purposes, that’s about as worrisome.
You can, but it’s pointless, unless you think that “life similar to our own” has a significant chance of arising independently of ours. The argument “we are here, so it stand to reason that someone like us would evolve elsewhere” is the generalization from one example (and also a failure of imagination) that I am so dubious about. I see no reason to believe that even given a more or less exact replica of the Solar system (or a billion of such replicas scattered around the Galaxy or the Universe) there will arise even a single instance of what we would recognize as intelligence. This may change if we ever find some non-Earth-originated lifeform. (Go, Curiosity!) Until then, the notion of the Great Filter is just some idle chat.
As you should be.
So in a nutshell in the framework of standard discussions about Fermi issues and the Filter one would just say that one heavy filtration step is that intelligent life as we know it seems unlikely to arise.