The case for panspermia seems simpler than Sleeping beauty, as it doesn’t include possible worlds. Imagine that there are two regions of the Universe, in one of which panspermia is possible and in another is not. The one where it is possible has, 100 times more habitable planets per volume. This suggests that we are more likely to be in the region in which panspermia is happening.
On the other hand, if you simply tried to approximate median human age by doing that estimate at every year, then your results would be pretty bad. Most of the estimates would be very off.
Most of the estimates will not be very off. 90 per cent of them will give the correct order of magnitude.
The case for panspermia seems simpler than Sleeping beauty, as it doesn’t include possible worlds. Imagine that there are two regions of the Universe, in one of which panspermia is possible and in another is not. The one where it is possible has, 100 times more habitable planets per volume. This suggests that we are more likely to be in the region in which panspermia is happening.
Most of the estimates will not be very off. 90 per cent of them will give the correct order of magnitude.