The difference in the growth rate of these functions illustrates the contrast between polynomial time complexity – which is currently taken by complexity theorists as the touchstone of feasibility – and exponential time complexity – which has traditionally been taken as the touchstone of intractability. For instance, if it could be shown that no polynomial time factorization algorithm exists, it might then seem reasonable to conclude that \(\sc{FACTORIZATION}\) is a genuinely intractable problem.