The Empiricist or Lockean view says natural kinds do not exist objectively in nature but are practical categories reflecting use of words. The Modern, Ostensive view says they do exist, and one can refer to such a kind by ostention and recursion, assuming his designation of it is related causally to the kind itself. However, this leads to a problem: Kinds are abstract repeatables, and it seems impossible that abstractions could have causal force. In defence of the Modern view, I (...) suggest we can think of kinds as — or as like — ecological niches existing in nature, which are causally effective by virtue of the fact that they predictively determine (some) properties of the things that happen to occupy them. (shrink)