AI has entered the domain of intelligence, a realm where human beings reigned supreme until recently. This development elicits both enthusiasm and fear. Yet, it also provides an epochal opportunity to focus on the most exquisite phenomena known to us: the human mind. The human reasoning mind possesses what we call ‘common sense,’ a humble term that belies the unfathomable depths of human reason, unattainable to any AI technology. ... In a quest for the science of human agency, this book adopts an interdisciplinary approach spanning fields such as AI, philosophy, history, economics, biology, child development, psychodynamic theories, cognitive science, and Perennial Philosophy. It explores what we know, what we believe we know (mistaking our beliefs for scientific knowledge), and what humanity understood at the dawn of Western civilization, when the human reasoning mind first gained prominence as a trustworthy instrument capable of engaging in philosophy and science. Beginning with the pioneering philosophers, we observe our increasing reliance on and trust in human reason. How did it all start? How did we manage to leave behind irrational beliefs and harmful traditions? Philosophy originated as a discipline aimed at developing inner virtue and cultivating an ‘intimate receptivity for wisdom’ through a set of ‘spiritual exercises’ (as termed by Pierre Hadot, a renowned scholar of classical antiquity). For its pioneers, philosophy was not a spectator sport. It was something one engaged in, not just something one talked about. What they did held profound transformative power: it reshaped their intimate inner experiences, fostered inner stability, curbed the irrational aspects of human reason, and limited the influence of raw self-interest. In doing so, they enhanced the trustworthiness of human reason and heralded a new era of humanist ethics. ...