 Psychologists have studied hundreds of different kinds of memory in addition to those described above. Many of these are defined in terms of specific laboratory tasks and are unlikely to qualify as natural kinds (Tulving 2007), kinds that carve nature—in this case, the mind—at its joints. But even if only the kinds acknowledged by the standard taxonomy are considered, it is not obvious whether any particular kind of memory, never mind memory as a whole, is a natural kind.