 Now, according to HF, the process by which one learns C must include the inductive evaluation of some such hypothesis as “The C things are the ones that are green or triangular”. But the inductive evaluation of that hypothesis itself requires (inter alia) bringing the property green or triangular before the mind as such… Quite generally, you can’t represent anything as such and such unless you already have the concept such and such. All that being so, it follows, on pain of circularity, that “concept learning” as HF understands it can’t be a way of acquiring concept C… Conclusion: If concept learning is as HF understands it, there can be no such thing. This conclusion is entirely general; it doesn’t matter whether the target concept is primitive (like green) or complex (like green or triangular).