Built Versus Natural Environment. We typically take built and natural environments to be clearly distinct. This distinction does at least two kinds of work in philosophy of architecture. For one, it helps establish what sorts of things we would discount as architecture even on an inclusivist conception—and even there, we might accept lived-in caves as found architecture but reject most other elements of the natural environment as non-architecture (because neither built nor found). For another, we get a defined sense of natural contexts into which built environments fit (or not), without which any such notions of fit are incoherent. If this is a viable (and desirable) distinction, it is perhaps less clear in what it consists. One candidate view is that we may distinguish the kinds of environments by their different sorts of objects and properties: we find columns in built environments and trees in natural environments and never the other way around. Alternatives highlight the ascribable functions and intent that mark built environments but not natural environments; or different sorts of behavior and obligations attached to the two kinds of environments. While an artifact-centered view of architecture weighs in favor of functions and intent as the most relevant distinction, decaying value of design intent over the life of a built structure may give pause.