To the Editor: In 1960, an astronomer proposed a mathematical model for determining whether extraterrestrial life exi...

Ben on May 6, 2020

Hi Eliyahu, thanks for the question.

A is incorrect because it describes life in general, however the conclusion specifically references life as we know it. Therefore, even if some other life did exist on other planets, it is not necessarily as we know it.

I hope this helps. Please let me know if you'd like me to elaborate further.