||Nonreductive materialism arose in the 1960s in response to the mind-brain identity theory before evolving into a more general anti-reductionist position of some diversity. Mind-brain identity theory, the earliest form of reductive materialism, asserts that mental states are identical to brain states. Nonreductive materialism denies this, whilst also asserting that materialism, the doctrine that everything is physical, was nevertheless true. The earliest defender of nonreductive materialism, Hilary Putnam, first developed the view via an analogy between computational properties and mental properties: that computational properties can be "realized" by different physical properties, such as mechanical or electronic properties, and that mental properties could be computational too, so also be realized by different physical properties. Thus the "multiple realization argument" was born. Nonreductive materialism then came to be understood as a "third way" between reductive materialist positions and abandoning materialism all together. And this promise led to a near nonreductive-consensus among materialists as the multiple realization argument swept virtually all before it. By the 1990s, however, the view became subject to increasing criticism, especially regarding the bona fides of its materialist credentials, its ability to accommodate mental causation, and the soundness of the multiple realization argument. This led both to the development of different versions of the view and a relative revival of reductionist approaches. The debate about these and related matters continues.