¹⁵This division into two kinds of uncertainty could be criticized on philosophical grounds. Laplace proposed that an intellect (called a “demon” by later commentators) which knows everything about the world, would be able to perfectly accurately predict everything, and nothing would be uncertain to it. Thus, from this viewpoint, uncertainty is always a reflection of ignorance about some aspects of the world. I shall not go into that debate here, and just acknowledge that the division I make here is not very rigorous, while in line with how randomness is handled in AI theory, and hopefully also in line with the common-sense idea of randomness. It is closely related to the distinction between “epistemic” and “aleatoric” uncertainty discussed by Hüllermeier and Waegeman (2021).