This article discusses the problems which concepts pose for the attribution of thoughts to animals. It locates these problems within a range of other issues concerning animal minds (section 1), and presents a ‘lingualist master argument’ according to which one cannot entertain a thought without possessing its constituent concepts and cannot possess concepts without possessing language (section 2). The first premise is compelling if one accepts the building-block model of concepts as parts of wholes – propositions – and the idea that intentional verbs signify relations between subjects and such propositions. But I shall find fault with both (section 3). This opens the way for recognizing a form of ‘holodoxastic’ thought-ascription which does not presuppose concept-possession on the part of the subject (section 4). Section 5 defends this idea against objections. Section 6 turns to the second premise of the lingualist master argument. I press the idea of judgement into service as a label for conceptual thought that need not be linguistic and argue that the possession of concepts is an ability. Section 7 accepts that concept-possession requires the ability to classify rather than merely to discriminate, but suggests that this need not disqualify animals. In the final section I confirm this verdict by returning to the notion of judgement: classification is the deliberate and considered response to a range of options in a sorting or discrimination task. Notwithstanding appearances to the contrary, the capacity for such a response does not presuppose the linguistic ability to answer questions. Judgement is a feature of a type of problem-solving that we share with some non-linguistic creatures.