And, by now, I hope you know the quote was fabricated.
Interestingly enough, his belief in spontaneous generation and that spontaneous generation was impossible wasn't fabricated, more like paraphrased with a conclusion drawn. He also stated that with enough time, the impossible could become virtually certain.
Having nothing to do with this specific discussion, I discovered that he thought war crimes was an invention of the U.S before the Nuremburg Trials and that having nuclear weapons as a deterrent was undesirable.
His rationale in more than one area is less than rational.