but I can’t make sense of its thesis about hard steps being evenly spaced—it seems to be just assuming what it proves
Robin ran Monte Carlo simulations and included the results in the paper, including the large standard deviation. The estimates of the fraction of planets with intelligence with remaining habitable windows of a certain size come from those simulations. You can construct your own in MATLAB to test the result.
The paper apparently makes no attempt to model destructive forces. It doesn’t entertain the possibility of hard steps being undone. The history of life on the planet has seen some pretty epic scale destruction. So: I am rather sceptical whether such a model can have much of interest to say about the actual evolutionary process. I don’t think the model withstands the K-T extinction.
Robin ran Monte Carlo simulations and included the results in the paper, including the large standard deviation. The estimates of the fraction of planets with intelligence with remaining habitable windows of a certain size come from those simulations. You can construct your own in MATLAB to test the result.
The paper apparently makes no attempt to model destructive forces. It doesn’t entertain the possibility of hard steps being undone. The history of life on the planet has seen some pretty epic scale destruction. So: I am rather sceptical whether such a model can have much of interest to say about the actual evolutionary process. I don’t think the model withstands the K-T extinction.