Originally Posted by

**Dreamraider**
believe it or not there is a whole branch of philosophy that covers that very topic. It states that all knowledge is only good, true, or right as long it is useful.

But Hardy, one of the greatest mathematicians of the 20th century, said that the best math was entirely useless.

A Mathematician's Apology - Wikipedia, the free encyclopedia
And many mathematicians feel that way, too. Certainly the vast majority of modern research mathematics is very far removed from anything anyone would consider useful. Just consider the endless sequence of transfinite cardinals: an infinite hierarchy of infinite numbers, each infinitely greater than the previous one. Of what use are they?

And even math that eventually becomes useful, often does so only after decades or even centuries. Non-Euclidian geometry was first discovered by Gauss in the 1820's; and only found practical use when it turned out to be just the thing to express Einstein's theory of relativity in the early 1900's.

The subject of algorithms for factoring numbers was studied by the ancients; yet was utterly without any possible, conceivable use for millennia. But when computers were invented, the theory of factoring large numbers became the basis of public key cryptography, underlying all modern Internet security.

So if the only math that were done (or allowed, or funded, or taught) was math known to be useful; we would be missing out not only on a lot of very beautiful and important math; but also on math that would

*eventually* become useful ... even after two thousand years of uselessness.

Finally, there may be some philosophers who hold that a thing in this world only has value to the extent that it's useful.

Many others would disagree. What's the use of a beautiful sunset? An ugly sunset would serve the same function.