We have entered an evolutionary cul-de-sac, Peter.

Despite all their powers and their brilliance, the Overlords were trapped in some evolutionary cul-de-sac.

They were still unspecialized; they had not yet become trapped in any evolutionary cul-de-sac.

Like Europa on a vastly grander scale, Jupiter was an evolutionary cul-de-sac.

And somewhere in the beginning-a few billion years ago-their precursors were trapped in an evolutionary cul-de-sac.

And somewhere in the beginning - a few billion years ago - their precursors were trapped in an evolutionary cul-de-sac.

Yet, while humanity has gone on to ever more complex achievements in philosophy, athletics, art, and technology, the nonproductive dolphin has apparently swum into an evolutionary cul-de-sac.

The planet is fine, he argues; it's we the people who have become "an evolutionary cul-de-sac, a surface nuisance."

An evolutionary cul-de-sac, Lacci.