Two days later, as he walked through the lobby of the Four Seasons, Hassabis explained the machine’s collapse. AlphaGo had assumed that no human would ever make Move 78. It calculated the odds at one in ten thousand—a very familiar number. Like AlphaGo before him, Lee Sedol had reached a new level, and he said as much during a private meeting with Hassabis on the last day of the match.
