Space-time is a four-dimensional abstract space, an analytical tool used in carrying out the program of relativity theory. That program requires that the laws of physics be stated in mathematical forms that remain unaffected - that are not changed - by the motion of the coordinate system in which they are applied. The nature of time, as understood in the context of space-time, differs from the common idea of time in that it makes no provisions for a "now" - for a present - and for the passing of time. Ideas about a present instant and about the passage of time have to be imported into physics from domains of knowledge outside physics. With the help of evolutionary epistemology based on evolutionary ontology, this paper locates the time of relativity's space-time in the integrated, interdisciplinary study of time.