The reason for all this has to do, primarily, with timescales. For starters, when it comes to alien intelligence, there’s what Schneider calls the “short window observation”—the notion that, by the time any society learns to transmit radio signals, they’re probably a hop-skip away from upgrading their own biology. It’s a twist on the belief popularized by Ray Kurzweil that humanity’s own post-biological future is near at hand.

“As soon as a civilization invents radio, they’re within fifty years of computers, then, probably, only another fifty to a hundred years from inventing AI,” Shostak said. “At that point, soft, squishy brains become an outdated model.”