In response to Cornerstones of attachment research and the target articles, I reflect on three questions. First, what is attachment? Although a natural kind, I argue against an essentialist understanding (i.e. in terms of necessary/sufficient conditions for class membership). Instead, the attachment concept must be allowed to have fuzzy boundaries, partly because of how attachments transform in both phylogeny and ontogeny. Second, how to think about the normative (species-typical) features of the theory vis-a-vis dyadic/individual differences in attachment? Whereas the former are foundational, I argue that the latter largely reflect surface variation. Despite this, the lion's share of attachment research has horned in on variation and its measurement, to some detriment to the theory's potential and applications. Finally, what is encouraging and discouraging about recent developments? While applauding large-scale cooperative endeavors (e.g. individual participant meta-analyses, consensus statements) I caution the field not to lose sight of the value of smaller-scale, creative explorations of uncharted territories.