Mathematics

I've been adding 2+2 all day, and I keep getting the number 5 as the answer. Does the number 4 not exist, or do we just perceive it differently?

Comments

I think I need to know a little more about what you're doing that keeps leading to the number 5. Perhaps you are putting two rabbits in a box, and then putting in two more, and then counting how many rabbits are in the box, and by the time you count them they have already reproduced. In that case, your method of computing 2+2 is flawed--perhaps you should switch to using only male rabbits. Or perhaps the way you count is "one, two, three, five, six, ..." In that case, I'd say that you're using the word "five" in the way that the rest of us use the word "four". That doesn't change the mathematical facts--2+2 is still 4--it just means that you're expressing that fact in a confusing way. (For more on this, see question 216.)

By the way, I assume that your story isn't true--you haven't really been adding 2+2 and getting 5, you're just saying that to make a philosophical point. The reason I'm making that assumption is that there is nearly universal agreement among different people about the facts of mathematics--at least basic facts like those of arithmetic. Even when people get different answers to math problems, they can generally resolve the disagreement by checking their work and finding that one of them made a careless error. This is a remarkable fact about mathematics, and it seems to me any adequate philosophy of mathematics should provide an explanation for it.

Read another response by Daniel J. Velleman

Read another response about Mathematics