Overall Conclusions

All three layers of representation described in the manifesto are in place. Part III started from functions and causes, assumed to be part of the pre-representational, natural world, and follows the teleosemanticists in using them to identify a primordial kind of ‘source’ intentionality. This lays the basis for running the metaphysics of belief and desire content explored in ...

Laying the Foundations

This chapter outlines a metaphysics of the representational content of action and perception. This is built on a teleosemantic account of perceptual content borrowed from Neander, which is here generalized to give an account of the content of action-guiding states. The key ingredient of such stories is an account of biological function, and this chapter lays out and responds to a central challenge to such approaches. After presenting Neander’s account, the chapter will show how to generalize this to the case of action-guiding states. The final section of this chapter takes a final look at these, the ultimate basis for representation on my three-layer story.

From Mental Representation to Linguistic Representation

This chapter is one of three that sets out a metaphysics of linguistic representation, and here the basic features of the approach is set out. The base facts for linguistic representation are conventional associations between sentences and propositions (the propositions being the contents of beliefs conventionally expressed by the sentences). The correct linguistic interpretation is then selected as the best theory of this data. The chapter considers two preliminary objections to the approach: an alleged need for a prior and independent identification of words and language-using populations, and an inability to handle declarative sentences that fail to express beliefs—a presupposition of expressivism. Both charges are rebutted.

Reducing Mental Representation?

This chapter evaluates whether Radical Interpretation as it has been articulated in this book can be a reduction or foundational metaphysics of mental representation. One can be worried about this from two angles: first, whether it really qualifies as foundational metaphysics; second, whether what it targets is the whole of mental representation. Both challenges are addressed here. The chapter defends a reductive, foundational construal of Radical Interpretation against charges of circularity, while acknowledging a more modest fallback construal of what it achieves. It also shows how to extend the metaphysics of reference and truth conditions of the previous chapters to a metaphysics of Fregean sense.

Elegant Interpretations

This chapter is the third of three that sets out a metaphysics of linguistic representation, and the focus here is on the way that correct linguistic interpretation is selected. The correct interpretation is the best theory of the linguistic conventions, and the best theory optimizes simplicity (elegance) and fit with the data. It is argued that elegance should be understood relative to the language-users’ pooled conceptual repertoire, and the combined theory of representation in language and thought is wielded to resolve indeterminacy puzzles. The appeal to simplicity/elegance in this context is compared to appeals to simplicity/elegance in the context of the metaphysics of mental content, where a rather different approach was examined. The compatibility of the two approaches is assessed.

Linguistic Convention and Shared Mental Content

This chapter is the second of three that sets out a metaphysics of linguistic representation, and here I turn to the key ingredient of linguistic convention. The focus is on a tension between the apparently individualistic character of the metaphysics of mental representation given by Radical Interpretation, and the presupposition of shared mental content apparently presupposed by appeals to linguistic convention. By considering the way in which beliefs about others’ beliefs influence the metaphysics of mental representation, the apparent tension is resolved. Either belief-attributions characterize others’ mental states indirectly, as having content somehow related to the contents used to characterize them, or they don’t. In the first case, there is no presupposition of shared mental content in the characterization of conventions. In the second case, there is such a presupposition, but Radical Interpretation will predict that there is metasemantic pressure to attribute shared content.

Radical Interpretation and the Referential Stability of Wrongness

This chapter is one of three that draws out the consequences of Radical Interpretation for how concepts represent the world. This chapter introduces a famous ‘moral twin earth’ puzzle about the normative concept wrongness. It appears to have a distinctive referential stability: individuals or whole communities can be very mistaken in what they think makes an act morally right or wrong, but somehow they remain locked onto the moral subject matter. This chapter derives this stability as a prediction of Radical Interpretation. Radical Interpretation predicts the result when combined with first-order normative premises and premises about the conceptual role of the concept of wrongness.

Radical Interpretation and Reference Magnetism

This chapter is one of three that draws out the consequences of Radical Interpretation for how concepts represent the world. A claim associated with David Lewis is that metaphysically fundamental properties are ‘reference magnets’—that if usage is equipoised between two candidate referents, the one that is ‘closer to the metaphysical fundamentals’ is the one that gets to be the referent. This chapter examines how such a thesis might arise as a prediction of Radical Interpretation. It looks to epistemology of inference to the best explanation to make a connection between concepts used in explanations and naturalness. The connection to concepts used in induction is discussed.

Radical Interpretation and the Logical Form of Thoughts

This chapter is one of three that draws out the consequences of Radical Interpretation for how concepts represent the world. The focus in this chapter is on logical concepts: conjunction, negation, and universal generalization. This connects Radical Interpretation as a foundational theory of mental content to inferentialism, where commitment to certain kinds of rules of inference or coherence is cited to explain why our connectives mean what they do. Radical Interpretation, together with auxiliary assumptions about cognitive architecture and epistemology, predicts these patterns. One of the upshots is an explanation of how quantification over absolutely everything is possible, rebutting long-standing skolemite underdetermination puzzles.

Radical Interpretation as a Metaphysics of Mental Content

This chapter sets out the metaphysics of the mental content of belief and desire that is the focus of the first five chapters of the book: Radical Interpretation. This says that the correct interpretation of an agent is that which best rationalizes the agent’s actions given their evidence. Radical Interpretation therefore combines two ingredients to ground mental content: a set of base facts involving an agent’s action and evidence, and a relation of rationalization. The chapter makes progress on the second of these, with the ‘bubble puzzle’ being used to argue that the relation of rationalized involved must be a substantive one. The best rationalizing interpretation of an agent will make that agent as morally and epistemically good as possible.