[js1138]

Dr. Crick won a Noble Prize and he believed in space aliens.

Anyone can believe anything they please.

It isn't science unless it is productive. Ideas must suggest research if they claim to be scientific.

[pby]

Are you suggesting research for Dr. Crick's "theory" (word used in the less concrete sense...I know) of Directed Panspermia?

[pby]

Is it scientifically "productive" to speculate that aliens seeded the Earth with life, via rocket ships?

And who determines the benchmark and standard that defines productive?

It seems pretty subjective if you ask me.