 The upshot of these remarks is that ‘knowledge’, ‘belief’, and ‘opinion’ are not, as idealists would have it, species of the same genre, ‘judgement’ or ‘thinking’: these are all distinct and sui generis. This leads to the all-important distinction between ‘knowledge’ and ‘belief’, discussed in the next section: they do not merely differ in kind, they are not even two species of the same genus (Prichard 1950, 87). But Cook Wilson also held the view that knowing is more foundational, so to speak, as it is presupposed by other ‘activities of thinking’ such as judging and opining. For example, opinion involves knowledge, but goes beyond it: