It is widely believed in philosophy of science that nobody can claim that any verdict of
science is forced upon us by the effects of a physical world upon our sense organs and
instruments. The Quine-Duhem problem supposedly allows us to resist any conclusion. Views on
language aside Quine is supposed to have shown this decisively. But it is just false. In many
scientific examples there is simply no room to doubt that a particular hypothesis is
responsible for a refutation or established by the observations. Fault Tracing shows how to
play independently established hypotheses against each other to determine whether an arbitrary
hypothesis needs to be altered in the light of (apparently) refuting evidence. It analyses real
examples from natural science as well as simpler cases. It argues that when scientific
theories have a structure that prevents them from using this method the theory looks wrong
and is subject to serious criticism. This is a new and potentially far-reaching theory of
empirical justification.
