Chalmers on stage for an Alan Turing Year
event at De La Salle University, Manila, 27
March 2012
Hard problem of consciousness
In the philosophy of mind, the hard problem of consciousness is to explain why and how humans and
other organisms have qualia, phenomenal consciousness, or subjective experience.[1][2] It is contrasted
with the "easy problems" of explaining why and how physical systems give a (healthy) human being the
ability to discriminate, to integrate information, and to perform behavioral functions such as watching,
listening, speaking (including generating an utterance that appears to refer to personal behaviour or
belief), and so forth.[1] The easy problems are amenable to functional explanation—that is, explanations
that are mechanistic or behavioral—since each physical system can be explained (at least in principle)
purely by reference to the "structure and dynamics" that underpin the phenomenon.[1][3]
Proponents of the hard problem argue that it is categorically different from the easy problems since no
mechanistic or behavioral explanation could explain the character of an experience, not even in principle.
Even after all the relevant functional facts are explicated, they argue, there will still remain a further
question: "why is the performance of these functions accompanied by experience?"[1] To bolster their
case, proponents of the hard problem frequently turn to various philosophical thought experiments,
involving philosophical zombies (which, they claim, are conceivable) or inverted qualia, or the claimed
ineffability of colour experiences, or the claimed unknowability of foreign states of consciousness, such
as the experience of being a bat.
The terms "hard problem" and "easy problems" were
coined by the philosopher David Chalmers in a 1994 talk
given at The Science of Consciousness conference held in
Tucson, Arizona.[4] The following year, the main talking
points of Chalmers' talk were published in The Journal of
Consciousness Studies.[1] The publication gained
significant attention from consciousness researchers and
became the subject of a special volume of the journal,[5][6]
which was later published into a book.[7] In 1996,
Chalmers published The Conscious Mind, a book-length
treatment of the hard problem, in which he elaborated on
his core arguments and responded to counterarguments. His
use of the word easy is "tongue-in-cheek".[8] As the
cognitive psychologist Steven Pinker puts it, they are about as easy as going to Mars or curing cancer.
"That is, scientists more or less know what to look for, and with enough brainpower and funding, they
would probably crack it in this century."[9]
The existence of the hard problem is disputed. It has been accepted by some philosophers of mind such as
Joseph Levine,[10] Colin McGinn,[11] and Ned Block[12] and cognitive neuroscientists such as Francisco
Varela,[13] Giulio Tononi,[14][15] and Christof Koch.[14][15] On the other hand, its existence is denied by
other philosophers of mind, such as Daniel Dennett,[16] Massimo Pigliucci,[17] Thomas Metzinger,
Patricia Churchland,[18] and Keith Frankish,[19] and by cognitive neuroscientists such as Stanislas
Dehaene,[20] Bernard Baars,[21] Anil Seth,[22] and Antonio Damasio.[23] Clinical neurologist and skeptic