 Assuming that  TSB  is weaker than  Definability,  it is arguably too weak to capture the intuitive idea that a description of the world in terms of perfectly natural properties should be a “complete” description. Indeed, the claim that properties that not perfectly natural are definable in terms of perfectly natural properties seems to be required for the simplicity-of-definition criterion to yield sensible results. Moreover, many of those who see a gulf between definability and mere supervenience have also felt that there is something metaphysically suspect about infinite descending chains of definability. If we can find a way to spell out a ban on such chains, it will plausibly imply that every property is fully definable out of indefinable properties (and objects); and this claim will in turn  Definability  if we take indefinability to imply perfect naturalness, as in (3) or (6) above. 