(May 8, 2019 at 10:52 pm)vulcanlogician Wrote: I thought this was a logical and realistic analysis...
Interesting video. I don't particular find his reasoning to be convincing when he attempts to deal with the early existence of life on Earth. The problem with his analogy is that there is an artificial time constraint on the 'prisoners' picking the lock of their cells. For this analogy to hold up, there would have to be some strict time limit on when life has to get started on a newly formed planet. Unless the parent star has to be in a very specific stage of its development (T-tauri, maybe?), this doesn't seem likely.
On the other hand, we are dealing with an N=1 scenario at this point.
But, I can go a bit further. While life got started very quickly on Earth, the transition to Eucayotic life (complex cells) and multi-cellular life took a pretty long time. So, while bacterial (procaryotic) life was around within a few hundred million years after the Earth cooled enough to have liquid water, eucaryotes don't appear for about another 2 billion years and multicellular life took almost another 1.5 billion years. This suggests both of these stages are much harder to get than life itself. Once we got multicellular life, getting to intelligent life took another half a billion years. Difficult, but not the hard step.
Because of this, my *guess* is that bacterial life is common in the universe but complex cells and multicellularity are much less common. Getting through the 'oxygen crises' where molecular oxygen becomes common also seems like a tricky step.
Another factor for *intelligent* life is how long a technological civilization can last without destroying itself. Humans only went through the industrial revolution a couple hundred years ago. We managed the first radio transmission about a hundred years ago. But it looks like we now have the power to kill ourselves off in multiple ways (nuclear, climate, etc) and whether we will keep this technological advance is far from certain.
What if technology is counter to long term survival of the species? Maybe no species manages to be technological for more than, say, 10,000 years. This is a *blip* on the cosmic scene. If this is the case, the likelihood of two technological civilizations existing at the same time within a galaxy starts to become pretty low.
We may be alone simply because technology is dangerous and technological civilizations don't last very long.
