"Any sufficiently advanced ETI is indistinguishable from God."

It's Michael Shermer's modification of the third law of Arthur C. Clarke's famous three laws. It was first mentioned in Shermer's column Skeptic in the January 2002 issue of Scientific American Magazine.

Shermer formulated his law to point out that if we were to make contact with an Extraterrestrial intelligence, they would probably be vastly superior to us. Because on an evolutionary time scale, an Extraterrestrial intelligent species that's only slightly ahead of us biologically could be millions of years ahead of us technologically.

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