> This is implicit on the meaning of that word. I was still in pre-school, watching a documentary about uranium. I asked my mother what uranium was, she replie

> This is implicit on the meaning of that word. I was still in pre-school, watching a documentary about uranium. I asked my mother what uranium was, she replied "a silver metal used for electricity generation". That answer felt deeply unsatisfying, but that's the best answer a todler could get from a village housewife in the year the internet was invented. But I learned that "understanding" doesn't have an objective benchmark; we understand a concept when we subjectively feel confident about our knowledge regarding that concept, no matter how ill deserved the confidence.