🚀 go-pugleaf

An earlier poster has written
>
> Au contraire!  Our ignorance about origin of life is profound, and
> very little progress has been made in dispelling it.  There is no
> really plausible model for the origin of life.  We're missing at least
> one, and possibly several, fundamental ideas.

It may have been pointed out earlier, in which case my apologies, but the
early emergence of prokaryotes can be construed as weak evidence that
their development was straightforward.  The relatively late emergence of
eukaryotic cells is weak evidence that this is difficult, with events of low
probability being required.  So little is known of this latter evolutionary
step that there is not even much speculation about it.

The evolution of multicellular organisms with complex internal structure
from simple eukaryotes appears to be straightforward.  Something can be
said about which of the resulting basic body-forms might eventually evolve
to support cognition - is an intelligent lobster possible, for instance?
The probability that body-forms which can so evolve will survive is
extremely difficult to estimate, and could well be minuscule, as S.J. Gould
and the debate about his book "Wonderful Life" has shown.

All in all, IMHO, it is not our knowledge but our ignorance that justifies
a modest SETI.  The most optimistic "reasonable" estimate of the factors
in the Drake equation leads to the conclusion that detectable
ET civilisations should be common in our galaxy; the most pessimistic
"reasonable" estimate suggests that ETI may occur in only a minute
fraction of the galaxies in the Universe.  As the laws of nature are the
same everywhere, it is prudent to look and listen about us.

My apologies if these points have been discussed previously.

John Lewis
Physics
Memorial University of Nfld.