Abstract

The present paper uses Carnap's reduction concept to address the problem of new severe acute hepatitis in children. First, it tries to show how that concept can help understand why some previous hypotheses of causality on the new hepatitis in children should be rejected. Second, Carnap's reduction concept is used to explain a complex hypothesis about the causes of that disease proposed in The Lancet in 2022. The latter hypothesis combines several factors: infection by SARS-CoV-2, a build-up of this virus in the bowel that comes in contact with blood circulation, and another infection by adenovirus. One of the points of the paper is to argue that a hypothesis can be described by means of a bilateral reduction sentence, which in turn would allow empirically comparison of the hypothesis in an easy way. Finally, the author considers a current cognitive framework, namely, the theory of mental models, to propose that bilateral reduction sentences should not be hard to handle for physicians or scientists.