After all, he is a proponent of listening via radio to the universe in order to
detect signs of intelligent life "out there."

"Out there," yes, somewhere, and at some time frame within the anals of cosmic
history.  However, don't let the dramatic backdrop of Star Trek blind you:  It is
stupifyingly difficult to get from "out there" to here.  I seriously doubt if any
form of intelligence has ever survived, or ever will survive, long enough to
achieve that accomplishment.

Why?  The energy densities of modern technology, and the capabilities of modern
science, and the collective will of our society, are several orders of magnitude
too feeble for interstellar travel, and yet nuclear warheads are already easily
sufficient to destroy all vertibrate life on Earth.  Furthermore, this ability to
destroy ourselves is, for all realistic purposes, already in the hands of just
about any splinter cult on "some fool idealistic crusade."

There will therefore come a time when just about anybody will have access to energy
densities capable of destroying humanity.  Since that capability is pretty nearly
already here, and since we have many hundreds, if not thousands, of years of
technology ahead of us before we'll be capable of the unfathomably enormous energy
densities necessary for routine interstellar travel, I think it's pretty clear that
we will destroy ourselves before we are capable of interstellar travel.

Furthermore, the sort of idealism that will probably lead to world destruction is a
necessary result of the evolution of brains-over-brawn creatures, in a world in
which the brawn-over-brains creatures could kill them.  That sort of evolutionary
heritage inherently results in, or at least involves, knowledge of one's self,
one's tribe, and one's beliefs and ideals, along with the desire to preserve them
at all costs.  It appears likely that, on any planet that can evolve a
technological society, long before they have the capability of interstellar travel,
somebody will apply this evolutionary baggage to their particular beliefs and
ideals.  Given many hundreds of years, it's bound to happen, and our to do so
improves with time.

Now, granted, there are and will be initiatives to keep these energies away from
"just anybody," and I certainly salute those efforts.  If we pursue them
vigorously, they'll probably buy us a few hundred years.  With a little luck we'll
be able to use that reprieve to get a thriving Mars colony before the humans left
on Earth destroy their planet, thereby - hopefully - also destroying their means of
spreading that destruction on to the thriving Mars colony.  Then the inhabitants of
that Mars colony will probably thrive sufficiently to face the same problem as the
inhabitants of Earth did.  A Mars colony, however, will be vastly more fragile than
Earth.

Sorry folks, I'm not trying to sound like a doomsday prophet, or even a pessimist.
It's just that looking at the problem reasonably as far as I can tell, I simply
don't see any way around this fate.  Technology is not bad, because it's the only
way we'll make it to the planets and the stars, but our evolutionary heritage will
make it a real nail-biter at best as to whether we'll make it there before we
destroy ourselves.  It seems highly likely that most any society on any planet will
have their fate similarly sealed.  The particular details of their evolution will
be different, but I can see no reason why their big picture would be substantially
different.