 Beyond the core ideas above, however, the theoretical landscape of Bayesianism is quite as hopelessly diverse as it is fertile. Surveys and state of art presentations are already numerous, and ostensibly growing (see, e.g., Good 1971; Joyce 2011; Oaksford and Chater 2007; Sprenger and Hartmann 2020; Weisberg 2015). For the present purposes, attention can be restricted to a classification that is still fairly coarse-grained, and based on just two dimensions or criteria.