 He therefore adopted a method from Carnap to overcome this difficulty, where, instead of attributing the property in question to anything not subject to the test, the predicate is partially defined by means of a reduction sentence, such as “if, at \(t\), a small iron object is close to \(x\), then \(x\) is magnetic at \(t\) if and only if it moves toward \(x\) at \(t\)” or symbolically,