Bay seniors who subscribe to Isaiah Berlin’s credo to know more at the end of their lives than at the beginning, might want to consider the rich menu of classes available here. Osher Lifelong Learning operates programs in San Francisco, Marin and across the East Bay. Here’s a sampling of their limited but stimulating summer classes. At OLLI in Berkeley there are investigations into Mary Magdalene and America’s Cup. SFSU in San Francisco has a course in digital photography. In San Rafael, you can study up on the history of baseball. Down the Peninsula the catalogue for Stanford’s Continuing Studies program will be available April 29.