Quoting historian Arnold Toynbee, Richard Leakey writes: “This spiritual endowment of [man] condemns him to a lifelong struggle to reconcile himself with the universe into which he has been born. ”
क्रमविकास से जुड़ी एक मूल समस्या है मनुष्यों और पशुओं के बीच बड़ा अंतर ।