perdurance in one common philosophical use, the property of being temporally continuous and having temporal parts. There are at least two conflicting theories about temporally continuous substances. According to the first, temporally continuous substances have temporal parts (they perdure), while according to the second, they do not. In one ordinary philosophical use, endurance is the property of being temporally continuous and not having temporal parts. There are modal versions of the aforementioned two theories: for example, one version of the first theory is that necessarily, temporally continuous substances have temporal parts, while another version implies that possibly, they do not. Some versions of the first theory hold that a temporally continuous substance is composed of instantaneous temporal parts or ‘object-stages,’ while on other versions these object-stages are not parts but boundaries. See also IDENTITY, METAPHYSICS , PERSONAL IDENTITY. J.Ho. & G.Ro.