Amartya Sen is often described as an insightful critic of mainstream economics, and in particular, his work in development economics, alongside the construction of the capabilities approach, has been associated with endeavors to revisit both the theory and practice of the discipline. Despite his in-depth criticisms of certain aspects of mainstream economics, Sen's extensive use of formal methods is suggestive of an ontological tension, one identified by Thorstein Veblen when commenting on some of his contemporaries and originally introducing the term "neoclassical." Veblen argued that the work of these economists involved both an implicit recognition of a causal processual social ontology he associated with modern, thoroughly evolutionary, approaches and a commitment to a taxonomic conception of science—the latter relying on a set of methods that presupposed an associationist ontology of event regularities. For Veblen, the adherence to taxonomic methods was the classical feature of their work, and the commitment to an evolutionary viewpoint was the neo aspect. This article argues that the same tension runs through Sen's contributions and that he is neoclassical in this specifically Veblenian sense. The assessment of the ontological inconsistencies in Sen's work is shown to shed light on its reception within the economics academy. [ABSTRACT FROM AUTHOR]