Questions on the nature of concepts in philosophy, psychology, and
cognitive science, such as ‘What are concepts?’ and ‘What is it to possess
a concept?’ are notoriously difficult to answer. For example, are concepts
abstract mind-independent objects in some Platonic or Fregean sense, or
are they better understood as mental representations, such as constituents
of thoughts? A common view in cognitive science is that thought is based
on word-like mental representations; some say that possessing a concept
C involves demonstrating some kind of ability with respect to C’s. But
which ability? Other longstanding issues concern a proper theory of the
structure of concepts. These questions are tackled here by Simon Baron-Cohen,
Peter Carruthers, and a distinguished cast of scientists and philosophers.