 These attempts to combine neutral monism with physicalism, or to reinterpret neutral monism along physicalist lines pose a serious challenge to neutral monism as usually understood. They deny the central claim that the fundamental building blocks of the world are neutral, i.e., nonphysical and nonmental. But no less noteworthy is the degree to which these versions of physicalism depart from more standard versions of physicalism. These nonstandard versions of physicalism agree with neutral monism in holding that physics provides an incomplete picture of the world. The disagreement is limited to a dispute about the nature of the materials that are needed to fill out the picture that physics provides. The neutral monist searches for something that is neither mental nor physical, in the traditional senses of these terms. The physicalists whom we are currently considering hope to find the missing materials in something that is physical, but not physical in the traditional sense of the term. This does suggest that the difference between neutral monism and this sort of physicalism may not be so deep after all (see Chalmers 2015 for more on this question).