 A worry about these proposals is that on some accounts, every property will count as partly definable from itself. Then (1) will be inconsistent, (2) will entail that no property is perfectly natural, and (3) will be vacuously true. The claim that partial definability is reflexive might, for example, be motivated by the claim that every property is the negation of its negation. It might also be motivated, at least as far as relations are concerned, by the especially plausible claim that every binary relation is the converse of its converse, together with the claim that the the converse of any relation is partially definable from  it.[60] 