The purpose of science is to give the most economical description of nature as possible, because science is to provide conceptions which can help us better orient ourselves to our world, and if science is uneconomical then it is useless in this regard. Put another way, Mach’s reason for insisting that economy must be a guiding principle in accepting or rejecting a theory is that uneconomical theories cannot fulfill their biological function, which, as we have seen previously, he insists is (in a