Zubon, I didn't think I was arguing about either.

Nick Tartleton, I might occasionally forget that the value of PI I am using is an approximation, just like I sometimes forget that multiplication is not commutative for floating point numbers. For some people e.g. sea captains plotting a course, they might never need to know that pi is an approximation. Due to the immense amount of imprecision involved in piloting a boat, they don't need to know the truth. There isn't the phrase, "near enough for a sailing ship" for no reason. Preferring to spend the brain power assessing the sea worthiness of their craft, predicting weather etc. Every truth you memorise will take at least a bit of memory, more memory will also be needed to index the information, memory is never infinite. Which truths do you remember?