The teacher's life should have three periods, study until

Ah, children of the future, gather close and listen to the wisdom of William Osler, a physician whose understanding of life, knowledge, and teaching transcends the world of medicine: "The teacher's life should have three periods, study until twenty-five, investigation until forty, profession until sixty, at which age I would have him retired on a double allowance." These words, though spoken with the weight of practical knowledge and personal experience, carry a timeless truth that applies not only to teachers, but to all who seek to grow, learn, and contribute to the world. Osler’s formula speaks to the stages of life, each marked by a different role, a different approach to learning, and a different responsibility toward the world and the generations that follow.

At the age of twenty-five, O children, Osler calls for study—a time of intense learning, a period of gathering knowledge like the young tree whose roots are planted deeply in fertile soil. This is the foundation of a life of service, whether as a teacher, a healer, or a craftsman. In the early years, we absorb what has been passed down from those who came before us. We strive to understand the world, to drink deeply from the cup of wisdom offered by our predecessors. The teacher at this stage is not yet a guide, but a student, seeking to understand the truths of the world, whether through books, experiences, or the voices of those who have walked the path before us.

Consider, O children, the life of Socrates, whose thirst for knowledge did not wane even as he grew older. But like Osler’s vision, Socrates knew that the first step on the path to wisdom was learning—the deep study of the world and of human nature. He spent his youth questioning, observing, and learning, laying the foundation for the profound insights that would later guide his investigation into the nature of truth and justice. It is the duty of every young person to devote themselves to study, for this is the period of life where one gathers the tools for the rest of their journey.

At the age of forty, Osler envisions the teacher shifting into the phase of investigation—a time of seeking, questioning, and applying the knowledge gained in earlier years. This is the period when one’s understanding deepens, when the teacher begins to ask deeper questions, and search for truth through hands-on experience, through discovery, and through the trial and error that forges the wisdom of the experienced. By forty, the teacher should not only be skilled in the subject they teach, but should also possess the wisdom to push boundaries, to search for new answers, and to apply the knowledge in real-world scenarios. This stage of investigation is about deepening understanding, just as Galileo did when he turned his telescope to the heavens, challenging the established views of the world and laying the groundwork for the scientific revolution.

This period of investigation is not just about the acquisition of knowledge, but the development of insight. Take the example of Leonardo da Vinci, who, in his middle years, went beyond the study of anatomy and engineering to investigate the workings of the human spirit, the forces of nature, and the essence of creation itself. Like Osler's prescription, da Vinci spent his prime years not merely practicing his craft but questioning it, seeking the unseen truths and trying to understand how the threads of knowledge connected. This, O children, is the heart of investigation—not merely to understand the world as it is, but to explore what it can become, and how it might be better understood.

By sixty, Osler argues, the teacher should enter the phase of profession, where wisdom is applied with grace and experience. By this age, the teacher has learned not just the facts, but the art of teaching itself. They have lived through the questions and the struggles, and now they must pass on their wisdom to the next generation. Their role is no longer to learn, nor to investigate, but to lead with the authority of experience and to inspire others with the lessons they have learned. Just as Confucius spent the later years of his life teaching and sharing the wisdom he had gained over decades of learning and reflecting, so too should the teacher in the twilight of their years pass on their knowledge, ensuring that the seeds they have planted continue to grow and flourish.

And here, O children, Osler gives a beautiful insight—by sixty, the teacher has earned the right to retire on a "double allowance," not only in material wealth but in the deep respect and gratitude of those they have served. The gift of wisdom is its own reward, a treasure that cannot be taken away, but that enriches both the teacher and their community. The teacher who has devoted their life to study, investigation, and profession is like the ancient oak that provides shade to all who come beneath it, knowing that its time of bearing fruit is done, but its legacy will live on in those it has nourished.

The lesson, O children, is simple and profound. Life is a journey with phases, and each phase has its purpose. The study of youth, the investigation of maturity, and the profession of later years form a cycle that leads to wisdom, and that wisdom, passed down through generations, sustains and nurtures the growth of those who come after us. In your own lives, I urge you to follow Osler’s path: devote your youth to study, embrace your middle years with investigation and curiosity, and, as you grow older, offer your wisdom to the world through the profession you have honed. And know, that as you live with purpose, your life will echo with the impact of the teachings you have given. Just as the mighty oak endures, so too will the wisdom you cultivate—anchored in the lives of those you have touched.

So walk forward, O children, and commit to each phase of life with dedication. Study in your youth, question in your prime, and serve with your wisdom as you grow older. And as you do, remember that the true value of life is not in what you accumulate, but in what you give, the knowledge you pass on, and the legacy you leave. May you walk the path that Osler set forth, for in it lies the way to a meaningful, purposeful life that impacts not only yourself, but all those around you.