Lessons from the 15th Century ring true for us today 3 January 2000 Q. How do you make God laugh? A. Tell him your plans. Today seems an especially appropriate time to recognize the truth in that old joke. Already over the threshold of the new year and standing on the doorstep of a new millennium, many of us will be tempted to start charting courses. Secure in the temporary stability of our lives, we look out across the future as if it were a landscape we'd already navigated; we forget that it's an undiscovered country. Future pleasures -- and future perils -- are yet to be encountered. But now and then we are reminded, in ways too powerful to ignore, that we aren't in control. When that potent lesson strikes home -- usually on account of events we didn't anticipate and can't control -- we need to know how to let go. Something in the modern temperament makes us seek jurisdiction over all the affairs of our lives. But the truth is, we don't reign supreme in any. A friend told me last month of a revelation that came while he huddled on the edge of an African game preserve where a group of Western tourists had recently been murdered. He was on assignment -- looking for news -- but strayed beyond the bounds of safety. After two nights of fear so intense he never slept, he came at last to a kind of peace: He thought he might die, but although he still felt foolish for getting into the predicament, he got over worrying about death. "At some point on the last night, I realized that my life truly is not my own. It's just on loan to me. It was given to me and sometime it will be taken away. I still honestly expected I might die, but once I had that revelation, the fear was gone," he said. Perhaps even more astonishingly, the effects of that revelation persisted. Months later, my globe-trotting buddy was aboard an airplane when a compressed air line exploded and sprayed the cabin with debris. The plane dropped 20,000 feet before making an emergency landing in Palm Springs. And again, fears raced out of control. "But that time, I made that whole journey, from terror to acceptance, in a minute or two," he said. "It was as if having the experience in Africa had pre-loaded the software in my brain, and this time it booted up quickly." I had never heard a spiritual experience described as a software configuration before, but whatever the explanation, my pal has clearly discovered a kind of peace he never knew before. I don't know where that insight will take him, but I can feel where it is taking me. Few of us find our moments of clarity under the canopy of an African jungle, but all of us must search. In a new book called "Galileo's Daughter," author Dava Sobel introduces us to the philosopher's beloved eldest child as a way to tell a story about the intersection of science and faith. The transcendent scientist Galileo Galilei -- who struggled all his life against the dogma of his church -- also entrusted his young daughter to a nunnery. Virginia Galilei lived most of her life cloistered within the walls of a small Italian convent as Sister Maria Celeste, but her formidable intellect still ranged the cosmos alongside her father in their frequent, loving correspondence. I found parallel lessons in their stories -- about the scientist who never lost religious faith and about the pious nun who continued to adore her father and embrace his discoveries. Both made room in their intellects for contending ideas, connecting beliefs with "and" rather than separating them with "or." Neither became captive of a single dimension; each bridged across to the other with love. Maria Celeste, the convent's apothecary, constantly counseled her father about his health and the prevention of disease. As a nun, much of her advice naturally focused on religious remedies -- nothing beats confession and penitence, she advised -- but her secular insights hold up through the centuries as well. Perhaps none resonated more with a contemporary reader than this admonition to her father: "This, without doubt, is the most efficacious medicine, not only for the soul, but for the body as well: given that living happily is so crucial to the avoidance of contagious illness, what greater happiness could one secure in this life than the joy that comes of a clear and calm conscience?" Words of advice from the 15th century ring down to us at the dawn of the 21st: Live happily, with a clear and calm conscience. I have heard no better prescription for the new year.