How do we know that Babe Ruth existed?

I am a fan of Sean "Mindscape" Carroll. He's a respected theoretical physicist, who has a chair in Philosophy at Johns Hopkins U. For his Mindscape Podcast he cast his net wide and pokes the expertise of his guest: chemistry, ecology, fashion, immunology, mathematics, medicine, oenology, philosophy, as well as physics. After an hour and a bit, I feel a bit better informed if not actually cleverer. Because clever is not about knowing stuff [Babe Ruth was 53 when he died; the Capital of Hungary is Budapest; Brobdingnagians are Big] it's about being able to process stuff. I know a lot - to wit decades of success in Table Quizzes. But there are limited areas [the chicken genome, Portuguese cats] where I know stuff because I've made it my business, through observation and research, to find things out from first principles. For everything else, I rely on trusted sources: hoping, assuming, trusting that someone else has done the deep digging. Because, for certain sure, we can't reinvent the…