The Universal Generative Faculty: The source of our expressive power in language, mathematics, morality, and music

•We propose that the expressive power of human thought derives from a computational system we call the Universal Generative Faculty or UGF.•UGF is a suite of contentless generative procedures that interface with different domains of knowledge to create contentful expressions.•The language of thought is, on our view, the more specific operation of UGF and its interfaces to different conceptual domains•This view of the mind changes the conversation about domain-specificity, evolution, and development.

Many have argued that the expressive power of human thought comes from language. Language plays this role, so the argument goes, because its generative computations construct hierarchically structured, abstract representations, covering virtually any content and communicated in linguistic expressions. However, language is not the only domain to implement generative computations and abstract representations, and linguistic communication is not the only medium of expression. Mathematics, morality, and music are three others. These similarities are not, we argue, accidental. Rather, we suggest they derive from a common computational system that we call the Universal Generative Faculty or UGF. UGF is, at its core, a suite of contentless generative procedures that interface with different domains of knowledge to create contentful expressions in thought and action. The representational signatures of different domains are organized and synthesized by UGF into a global system of thought. What was once considered the language of thought is, on our view, the more specific operation of UGF and its interfaces to different conceptual domains. This view of the mind changes the conversation about domain-specificity, evolution, and development. On domain-specificity, we suggest that if UGF provides the generative engine for different domains of human knowledge, then the specificity of a given domain (e.g., language, mathematics, music, morality) is restricted to its repository of primitive representations and to its interfaces with UGF. Evolutionarily, some generative computations are shared with other animals (e.g., combinatorics), both for recognition-learning and generation-production, whereas others are uniquely human (e.g., recursion); in some cases, the cross-species parallels may be restricted to recognition-learning, with no observable evidence of generation-production. Further, many of the differences observed between humans and other animals, as well as among nonhuman animals, are the result of differences in the interfaces: whereas humans promiscuously traverse (consciously and unconsciously) interface conditions so as to combine and analogize concepts across many domains, nonhuman animals are far more limited, often restricted to a specific domain as well as a specific sensory modality within the domain. Developmentally, the UGF perspective may help explain why the generative powers of different domains appear at different stages of development. In particular, because UGF must interface with domain-specific representations, which develop on different time scales, the generative power of some domains may mature more slowly (e.g., mathematics) than others (e.g., language). This explanation may also contribute to a deeper understanding of cross-cultural differences among human populations, especially cases where the generative power of a domain appears absent (e.g., cultures with only a few count words). This essay provides an introduction to these ideas, including a discussion of implications and applications for evolutionary biology, human cognitive development, cross-cultural variation, and artificial intelligence.