New materialism is not a clear-cut set of theses, or a firmly unified school of thought. It crosses discourses and theoretical commitments, but, as its name indicates, seems consistently to oppose ‘new’ materialism to an older form, or perhaps several older forms of this doctrine. The latter are typically associated with ‘mechanistic’ standpoints, with ‘reductionism’, with the denial of life, agency, embodiment, meaning, value … What happens when a historian of materialism confronts such claims? In what follows, I reflect on the historical problems which affect such theoretical positionings. It is not that there is no need to distinguish passive from active forms of materialism, or single out a focus on organic life. But that a distinction...