Today is my dad's 74th birthday. When I phoned him this afternoon to wish him a happy birthday, I pointed out that, as of today, he has overtaken Charles Darwin: Darwin only made it to 73, you see. I think dad could have done without that particular snippet of information.
It's funny, though: whenever I think of the elderly Charles Darwin—the one who wrote the earthworms book—I always think of him as a really old man. But I don't think of my dad as old (and neither does he); I just think of him as my dad—a man who went out into the snow today and came second in this weekend's competition at his local golf club.
Perhaps I shouldn't think of Charles Darwin as an old man, either. His mind was every bit as astute when he was 73 as it was when he was researching and writing On the Origin of Species.