In the philosophy of science, underdetermination is the idea that evidence available to us at given time may be insufficient to determine what beliefs we should hold in response to it. Underdetermination says that all evidence necessarily underdetermines any scientific theory In the philosophy of science, underdetermination is the idea that evidence available to us at given time may be insufficient to determine what beliefs we should hold in response to it. Underdetermination says that all evidence necessarily underdetermines any scientific theory