 However, a philosopher approaching belief with the specific goal of defending physicalism or materialism—the view that everything in the world, including the mind, is wholly physical or material (see  physicalism)—might  have reason to be dissatisfied with liberal dispositionalism, for the very reason that it abandons the reductionist project. Although liberal dispositional accounts of belief are consistent with physicalism, they do not substantially advance that thesis, since they relate belief to other mental states that may or may not be seen as physical. The defense of physicalism was one of the driving forces in philosophy of mind in the period during which the most influential approaches to belief in contemporary analytic philosophy of mind were developed—the 1960s through the 1980s—and it was one of the principal reasons philosophers were interested in accounts of propositional attitudes such as belief. Consequently, the failure of liberal dispositionalism to advance the physicalist thesis might be seen as an important drawback.