Paul Tran-Hoang

A formal theory is categorical if any two of its models are isomorphic, that is, there is a structure-preserving bijection between them. It is natural to think that whether or not categoricity is a virtuous feature of a theory depends on whether we have some antecedent belief that the theory in question describes a unique structure. In this paper, I put forth a purpose-relative framework for assessing the virtuousness of a metamathematical property. According to this framework, whether categoricity (or any other property) is virtuous depends more deeply on what we take the purpose or function of formal theories to be. I then develop one important purpose we would like theories to serve which I call the instrumentalist conception of formal theories. I argue that given this instrumentalist conception, categoricity is best understood as having somewhat limited virtue, and that, in contrast, uncountable categoricity is highly virtuous.

_This review provides an overview and assessment of Kevin Pham’s book _Architects of Dignity_, the first book-length treatment of Vietnamese political thought during the French colonial period. At the core of Pham’s book are novel claims about the nature of dignity and shame as explored by prominent Vietnamese political intellectuals of the nineteenth and twentieth centuries. According to Pham, these thinkers took dignity to be collective and to be asserted instead of being recognized by some dominant power. Moreover, Pham contends that they viewed shame as a productive tool for motivating political action. Overall, this book is an important and necessary contribution that introduces readers to some of the central themes animating modern Vietnamese political thought. At the same time, this review highlights some philosophical and political concerns regarding the main ideas and claims of the book._.

In a recent article, Barrett & Halvorson define a notion of equivalence for first-order theories, which they call “Morita equivalence.” To argue that Morita equivalence is a reasonable measure of “theoretical equivalence,” they make use of the claim that Morita extensions “say no more” than the theories they are extending. The goal of this article is to challenge this central claim by raising objections to their argument for it and by showing why there is good reason to think that the claim itself is false. In light of these criticisms, this article develops a natural way for the advocate of Morita equivalence to respond. I prove that this response makes her criterion a special case of bi-interpretability, an already well-established barometer of theoretical equivalence. I conclude by providing reasons why the advocate of Morita equivalence should opt for a notion of theoretical equivalence that is defined in terms of interpretability rather than Morita extensions.

In a recent paper, Barrett & Halvorson (2016) define a notion of equiva- lence for first-order theories, which they call “Morita Equivalence.” To argue that Morita equivalence is a reasonable measure of “theoretical equivalence,” they make use of the claim that Morita extensions “say no more” than the theories they are extending. The goal of this paper is to challenge this central claim by raising objections to their argument for it and by showing why there is good reason to think that the claim itself is false. In light of these criticisms, this paper develops a natural way for the advocate of Morita equivalence to respond. However, this response makes her criterion equivalent to mutual faithful interpretability, an already well-known and philosophically contentious barometer of theoretical equivalence.