How Do You Know What You Know?

There are the things that we know, like if we drop something, it'll fall, and there are the things we know - the things we couldn't really prove if we tried, that we can't explain why we know or how we know, just that we do. Years ago a friend of our family was in a nursing home. She was in her 90s, but very healthy and generally in control of her faculties. She stayed in the part of the home where you dress yourself and walk down to the dining room for meals. One day she told my mother that the hardest part of living in the home was trying to figure out if she was losing her mind or not. See, she's talk to someone, maybe say "Yesterday when we were playing cards . . ." and the other person would say "We didn't play cards yesterday" and they'd discuss it, but they're both 90 and in a home, who knows which one is remembering wrong? I'd argue that for her to think of that, she must have a better grip on things, but she's right, how can she know that she's the one who remembers correctly? Two other quick examples, both dealing with women and their skin . . . In high school, my friend used a homemade skin cleaner that was a family secret recipe thing. Her mom taught her to make it/use it when she was 11 and she never had a pimple. Her mom told me, "For four generations of my family, every woman used this and not one ever had acne." Now, this leads me to wonder, was it the super-secret cleanser? Or just a family not prone to acne? A few years ago, I worked with a women in her 50s, who was telling the other women in the office that every night and every morning she splashes her face with cold water, as cold as she can get it from the sink. "It prevents wrinkles." Her mother told her that. One of the other women asked if it really works, probably because while the cold-splashing woman wasn't super-wrinkly, she also wasn't wrinkle-free. The first woman assured her it did - "If I didn't, I'd have more wrinkles." That was her evidence. She just knew it. There's nothing wrong with some faith, and there's plenty of things in this universe that I can't explain, even mundane ones like how radio waves make music come out of the stereo. Sometimes I wonder, though, what do I know, and what do I know?