Maybe the probability of life spontaneously appearing is so low, that Earth is the only planet in the galaxy, or in the observable universe, in which it happened.

或许生命自然出现的可能性是如此的小，以致于地球是银河系中或可观测到的宇宙中的唯一的行星，在这颗行星中产生了生命。

youdao

The probability of a false positive in a chemical assay for a drug or poison (something appearing to show up when it isn't really there) is reasonably well known.

ECONOMIST: Whose body of evidence? | The