What do four-year-olds have in common with Frege? Marian Counihan Abstract: False beliefs involve attributing to another the attitude of belief towards a counterfactual proposition. Here I have considered various aspects of the attribution of false beliefs: firstly, that it involves recognition of the possible non-existence or falsity of objects of thought (objects are objects in the world and propositions respectively). This is captured by the concept of the intentionality of the mental. Advancement in false-belief mastery thus may indicate acquisition of the concept of intentionalty. This can also be understood as the replacement of an act-object dichotomy with a tripartate account of experience. Secondly, studies with deaf children raise the possibility that linguistic structures play a role in false belief mastery. Using linguistic criteria devised to ascribe intentionality to sentences, one may test children's understanding of other aspects of the concept, such as the failure of substitutivity in mental state ascriptions. There are also results from the psycholinguistic literature which suggest that the ability to attribute false beliefs emerges at the same time as recognition that beliefs can be held with differing degrees of certainty. This may also indicate sensitivity to the distinction between epistemic and deontic modalities, something the literature on this subject has so far not addressed. The late emergence of false belief attribution may also have to do with the dual nature of belief: it has traceable perceptual or inferential origins but nevertheless is distinctly tied to individual perspectives and thus is subjective. Growing awareness of the former quality of belief is one of the suggested interpretations of improving performance on the false belief task. Thirdly, false belief mastery may rely on skill in reasoning with counterfactual statements. Research suggests that these two competencies are highly correlated, but there are aspects of this proposal which need further elucidation, and which can be elucidated by discussions in semantic and philosophical literature. For example, the distinction between degree of speaker belief and hypotheticality should prove very relevant in interpretations of counterfactual reasoning tasks. Also, skill on these tasks may be underpinned by understanding of the nature of mental states, as captured by the concept of intentionality.