Above all, I would not expect a wise race, at great expense, to set loose an army of self-replicating robots.

If interstellar travel is as time- or energy- demanding as the above figures indicate, it is far from obvious what the motive for colonization might be.

It would be a pity if, frustrated by the price of travel, we elected to become a society that never made contact, that never gave SETI a fair chance.

The wise are above books.

I can't expect loyalty from the army if I do not give it.

In the past, on Earth, it has largely been to exploit foreign resources and to expand the domestic territory.