To say that you know that there is life on other planets necessarily implies that you believe there is life on other planets, that you have reasons to back up your belief, and that:
A) life on other planets is perhaps vastly different from what we are used to.
B) you can trust your senses when you see extraterrestrial life forms.
C) you have experienced life on other planets personally.
D) there is, in fact, life on other planets.

Question

Quizplus · Accepted Answer

To claim knowledge of life on other planets implies an assertion that such life actually exists, beyond just belief or reasons; it's a claim about reality, not just personal experience or speculation.

To Say That You Know That There Is Life on Other