Pi is the circumference of a circle divided by its diameter. Roughly speaking, that’s always about 3.14. In American-speak, that’s today. So today (I’m writing this on March 14th) is Pi day.
What I like about pi is that it is an example of the absolutely insolvable. Pi isn’t exactly 3.14. It’s 3.14 followed by an infinite stream of numbers. Literally infinite. So we can’t ever know exactly what it is. It’s a prime example of the state of human knowledge. Probably the inevitable, inescapable state of human knowledge: we know a lot about it and can always learn more by generating as many more numbers after .14 as we have time and energy.
But we can never know it absolutely. We can only know it “up to a point.” There will always be more we can learn, and we will never reach the final Absolute Perfect Truth.