 Ludlow (2002) argued that the Cartesianism in Russell’s psychology and epistemology led him into difficulties here. The problem is that we can be in error as to whether we are directly acquainted with someone (did I really have lunch with a colleague or was that a sophisticated hologram?) and this concern (coupled with the Cartesianism that Russell held at that point in his career) propelled Russell to radically minimize the class of cases where we have acquaintance—down to what he called “egocentric particulars,” which is basically to say I’m only acquainted with myself and sense data. This in turn led Russell to extend the theory of descriptions to almost all uses of names—treating them as definite descriptions in disguise.