Conceptualism in natural aesthetics takes knowledge of natural objects to be necessary for their appropriate appreciation. Concentrating on animals, I explore a particular version of conceptualism – functionalism – in light of debates about the effects of cognition on perception - so-called ‘cognitive penetration of perception.’ I establish the claims about cognitive penetration to which functionalism is committed, and assess the implications of its assumptions for the normative claim that functional appreciation is most appropriate to nature. I argue that functionalism (...) has not yet provided strong reasons for thinking that knowledge affects perception in the relevant ways, and in ways required by its normative claims. (shrink)