It's actually a problem with the semantic web generally: it tends to assume that the world is compartmentalizable into neat categories. Instead, we live in a wo

It's actually a problem with the semantic web generally: it tends to assume that the world is compartmentalizable into neat categories. Instead, we live in a world where (a) membership in categories is partial (b) membership in categories is probabilistic (c) membership in categories is contested (see Pluto for an innocuous example) (d) definition, legitimacy, etc. of categories is contested (e) category boundaries are vague, e.g. Sorites paradox: Base step: A one day old human being is a child. Induction step: If an n day old human being is a child, then that human being is also a child when it is n+1 days old. Conclusion: Therefore, a 36,500 day old human being is a child. (f) membership in categories changes with time etc... There are hot things, and there are cold things, and then there are things that are neither hot nor cold.