 There is, however, one form of curvature pathology associated with a particular form of an apparently important class of singularities that recently has been clearly characterized and analyzed, that associated with so-called conformal singularities, also sometimes called isotropic singularities (Goode and Wainright 1985; Newman 1993a, 1993b; Tod 2002). The curvature pathology of this class of singularities can be precisely pinpointed: it occurs solely in the conformal part of the curvature; thus, what is singular in one spacetime will not necessarily be so in a conformally equivalent  spacetime.[6]  This property allows for a boundary to be attached to the singular spacetime in a way that seems to be physically meaningful (Newman 1993a, 1993b; Tod 2002). Many physicists hold that, in a sense that can be made precise, all “purely gravitational degrees of freedom” in general relativity are encoded in the conformal structure (Penrose 1979; Gomes et al. 2011). These properties, along with the fact that the Big Bang singularity almost certainly seems to be of this form, make conformal singularities particularly important for the understanding and investigation of many issues of physical and philosophical interest in contemporary cosmology, as discussed below in  section 7.  