Timothy Murphy wrote
Rod Speed wrote

we have a few billion years to find out how
to do it, and its quite a laudable goal.

Sadly, unless human beings are completely different to other animals,

They clearly are.

That's your opinion because you are a human being.

Nope, its because no other animal has managed anything
even remotely like the industrial or computer revolutions,
or been able to work out how we all got here, etc etc etc.

The DNA of homo sapiens and chimpanzees are 98-99% identical.

And yet that small difference has seen homo sapiens manage
quite a bit more than chimps have ever managed.

it is extremely unlikely that they will survive for billions of years.

We don't know if any of the higher animals have done that yet.

But we can determine how long extinct species survived.

Sure, but don't know how long the ones that have not gone extinct yet will.

By definition, the ones that have gone extinct weren't
as successful as the ones that have not yet gone extinct.

The time for animals as large as us is millions, not billions of years.

Only because they haven't been around that long yet.

Rationally, it must be assumed that the likely future of
the human race is of the same order of time as their past.

Nothing rational what so ever about that assumption.

If you choose a point on a gaussian curve (normal distribution)
it is unlikely to be very far from the centre.

But you don't know that we can actually see
anything more than a small part of the curve yet.

Distributions depending on a large number of factors
are likely to be close to the normal distribution.

But you don't know how much of it is visible yet.

Radiation is easily solved with shielding.

Not so.
It is impossible to protect against cosmic rays;
and if you look at the figures you will see that even airline
pilots get far above the recommended dose of radiation.

All that shows is that the recommended dose is stupid.

People whose only argument against those holding the opposing
view is that their opponents are stupid, are themselves ultra-stupid.

It isnt the only argument. By definition, if we don't
see any major health problems with airline pilots, the
recommended dose must be much too conservative.

If you have some claim to judge better than the ICRP
(International Commission on Radiological Protection)
let us know.

We have the evidence of all those airline pilots doing fine health wise.