"The Rooster Crows, the Sun Rises" — Correlation Is Not Causation
Pearl often uses a plain example to show the difference of correlation and causation: the rooster crowing is highly correlated with the sun rising, but the rooster crowing is plainly not the cause of the sun rising. He holds that deep-learning systems relying only on vast data to find statistical correlation can in essence hardly escape such traps, and only by introducing an explicit causal structure can a machine truly understand counterfactual reasoning such as "what would happen if I did A," his core reason for keeping a cautious attitude toward the purely data-driven deep-learning path.