LECTURE 26
NEW VERSIONS OF DESCARTES’
ARGUMENT AND
THE LEIBNIZIAN ARGUMENT
G.E. MOORE’S OBSERVATION
DESCARTES’ ARGUMENT
I CAN CONCEIVE OF THERE BEING
NO PHYSICAL BODIES.
I CANNOT CONCEIVE THAT I DO
NOT EXIST.
THEREFORE:
I AM NOT A PHYSICAL BODY.
THIS ARGUMENT COMMITS A CERTAIN FALLACY
WHICH DOESN’T HAVE A STANDARD NAME
WE MIGHT CALL IT “THE FALLACY OF
SUBSTITUTING INTO AN INTENSIONAL CONTEXT”.
STILL, THE CARTESIAN THOUGHT EXPERIMENT
SEEMS TO HAVE SOMETHING TO IT. RECENT
ADVOCATES HAVE DROPPED TALK OF
“CONCEIVING” AND JUST SPOKEN ABOUT
POSSIBILITY.
THE CARTESIAN TYPE ARGUMENT IS NOT
DEAD
SAUL KRIPKE ARGUED THAT WE CAN SEE
THAT PAIN CANNOT BE A PHYSICAL PROCESS
BECAUSE, FOR ANY PHYSICAL PROCESS, SAY
“STIMULATION OF C-FIBERS”, IT IS POSSIBLE
FOR THERE TO BE PAIN AND NO SUCH
PROCESS.
SAUL KRIPKE (1940-
)
ALVIN PLANTINGA ARGUED
THAT IT IS POSSIBLE FOR EACH AND
EVERY CELL OF MY BODY TO BE
INSTANTANEOUSLY REPLACED AND
YET FOR ME TO CONTINUE TO
EXIST. IT CANNOT BE SAID THAT MY
BODY CONTINUED TO EXIST.
ALVIN PLANTINGA (1932 - )
• DAVID CHALMERS ARGUED THAT
“PHILOSOPHICAL ZOMBIES” ARE POSSIBLE.
SUCH A BEING HAS ALL THE PHYSICAL
CHARACTERISTICS OF A PERSON (THE BRAIN IS
FUNCTIONING NORMALLY AND NEURONS ARE
FIRING) AND YET IT DOESN’T HAVE
CONSCIOUSNESS. IF SO, THEN CONSCIOUSNESS
IS NOT A PHYSICAL PROCESS.
DAVID CHALMERS ( 1966-
)
LEIBNIZIAN ARGUMENT AGAINST
PHYSICALISM
(1)IT IS IMPOSSIBLE THAT PHYSICAL THINGS
SHOULD BE CAPABLE OF THOUGHT AND
PERCEPTION.
(2)I AM CAPABLE OF THOUGHT AND
PERCEPTION.
THEREFORE:
 (3) I AM NOT A PHYSICAL THING
THE LEIBNIZIAN-TYPE OF ARGUMENT IS NOT
DEAD
PLANTINGA HAS ARGUED THAT WE CAN SEE THAT
THINKING AND CONSCIOUSNESS COULD NOT BE
PRODUCED BY A PHYSICAL PROCESS. EVEN IF WE
CAN’T SEE HOW IT COULD BE PRODUCED IN A
NON-PHYSICAL BEING, WE DON’T SEE THAT IT IS
IMPOSSIBLE FOR THAT TO HAPPEN.
A THIRD ARGUMENT AGAINST PHYSICALISM IS
DUE TO G. E. MOORE
G. E. MOORE
A THIRD ARGUMENT THAT A PERSON IS NOT
A BODY
• G. E. MOORE’S OBSERVATION ABOUT “WHERE”
HE IS:
(1)I AM CLOSER TO MY HANDS THAN I AM TO MY
FEET.
(2) MY BODY IS NOT CLOSER TO MY HANDS THAN
TO MY FEET.
THEREFORE (BY DD):
(3) I AM NOT MY BODY.
VAN INWAGEN SUGGESTS THAT THIS
IMPRESSION IS DUE TO THE FACT THAT
OUR SENSE ORGANS (MOSTLY)
CLUSTER AROUND THE HEAD
HE SPECULATES THAT HELEN KELLER
WOULD THINK THAT SHE IS CLOSER TO
HER HANDS THAN TO HER HEAD.
VAN INWAGEN CONCLUDES THAT
NONE OF THESE THREE ARGUMENTS
ARE FORCEFUL AGAINST PHYSICALISM.
A FOURTH ARGUMENT AGAINST
PHYSICALISM: “THE SCORPIAN GOO ARGUMENT”
(1)IT IS POSSIBLE FOR THERE TO BE BEINGS THAT
ARE PHYSICALLY VERY UNLIKE US (SAY FROM A
GALAXY IN THE CONSTELLATION SCORPIO),
BUT WHO HAVE THOUGHTS AND FEELINGS
AND PERCEPTION.
(2) IF THIS IS POSSIBLE, THEN PAIN (FOR
EXAMPLE) CANNOT BE A PROCESS THAT OCCURS
IN OUR BRAINS – FOR NO SUCH PROCESS OCCURS
IN THE SCORPIANS.
OUR BRAIN PROCESSES ARE NECESSARILY NOT
“PURPLE GOO” PROCESSES
•THEREFORE, (3) MENTAL
PROCESSES ARE NOT BRAIN
PROCESSES.