Muhammad Ali Khalidi

In this paper, we consider how latent variables of mainstream quantitative psychology fits with two different models of scientific kinds. On the one hand, there is a good reason to think they fit with taxonomic and predictive success criteria that are popular within an epistemic understanding of scientific kinds. On the other hand, they conflict with widely shared person-based ontological commitments that underwrite psychological kinds because this research rests in large part on between-individual studies. We explore the implications of the different views on scientific kinds and argue that this is indeed a dilemma for the scientific discipline of psychology

Scientists often communicate using generic generalizations, which are unquantified generalizations such as ‘Americans overestimate social class mobility’ or ‘sound waves carry gravitational mass’. In this paper, I explain the role of such generic generalizations in science, based on a novel theory about their characteristic meaning. According to this theory, a scientific generalization of the form ‘Ks are F’ says that F is one property based on which category K qualifies as a scientific kind. Because what it takes to qualify as a scientific kind varies depending on the discipline, what a generic sentence entails also varies. Based on this semantic theory, I discuss the benefits and drawbacks of using generic language in science.