[Mark Felton]

"Nor do we know that they "needed" to. But we do know that they did, and by doing so made themselves more survivable. "

A force is a "need", per se.

"...I think a bit more information than that is needed before we can say "without doubt."

Nothing exists that is not the result of forces of various sorts, acting upon it, and within it. Since it, life, exists, without doubt a force, or series of consequential forces, exist that caused it to come into existence in the first place (by overcoming all other forces which worked in opposition to life).

[orionblamblam]

> Since it, life, exists, without doubt a force, or series of consequential forces, exist that caused it to come into existence in the first place

Yes. These are the forces that control chemcial reactions... electromagnetism, mostly. But a "life force" is just so much newage, unless you have some evidence of it.