1) Theoretical physics theories are more valid if they can predict new phenomena that can be tested, rather than just explaining existing phenomena. 2) The document presents three examples from network science that demonstrate both explanation and prediction: (i) predicting epidemic spreading, (ii) predicting abrupt breakdown of interconnected networks, and (iii) predicting El Niño events. 3) Research on coupled networks found that the robustness of interconnected networks decreases abruptly rather than continuously as networks become more complex, moving from a second-order transition to a first-order transition with cascading failures.