All of us, including scientists, make judgments about what is true or false, probable or improbable. And in the process, we frequently appeal to concepts such as evidential support or explanation. Bayesian philosophers of science have given illuminating formal accounts of these concepts. This paper aims to follow in their footsteps, providing a novel formal account of various additional concepts: the likelihood-prior trade-off, successful accommodation of evidence, ad hocness, and, finally, consilience—sometimes also called “unification”. Using these accounts, I also provide a new Bayesian analysis of how someone such as Charles Darwin hypothetically could have reasoned in favor of evolution over special creationism. Lastly, I explore how these accounts relate to other topics and accounts in philosophy, and I chart out some areas for further research.