LECTURE 24THE NATURE OF

PERSONSPHYSICALISM AND

DUALISM(“WHAT AM I?)

ORDINARY INDIVIDUAL THINGS (TABLES, CHAIRS, CABBAGES,….)

ORDINARY INDIVIDUAL THINGS ARE MADE UP OF PHYSICAL PARTS. A PHYSICAL PART OF SOMETHING IS AN INDIVIDUAL THING OF THE SORT STUDIED BY PHYSICS.

AT PRESENT (ACCORDING TO VAN INWAGEN) THE MOST BASIC SORTS OF PHYSICAL THINGS ARE THOUGHT TO BE QUARKS AND ELECTRONS (AND CERTAIN OTHER PARTICLES).

DEFINITION OF PHYSICAL THING

A PHYSICAL THING IS A THING COMPOSED ENTIRELY OF THE SORTS OF INDIVIDUAL THINGS INVESTIGATED BY PHYSICS. (OF COURSE PHYSICS MAY DECIDE THAT THERE ARE EVEN MORE FUNDAMENTAL INDIVIDUAL THINGS.)

WHAT AM I?WE ARE MORE FAMILIAR WITH OURSELVES THAN

WITH ANYTHING ELSE THAT THERE IS. BUT WHAT KIND OF THING ARE YOU?

(1) I AM A PHYSICAL THING: A LIVE HUMAN BODY. (PHYSICALIST ANSWER)

(2) I AM NOT A PHYSICAL THING. I AM AN ENTITY THAT HAS A BODY (AT PRESENT). I AM A NON-PHYSICAL THING: A MIND, A SOUL, A SELF, OR A “PURE EGO.” (DUALIST ANSWER)

ARE YOU IDENTICAL WITH YOUR BODY?

PHYSICALISM: A PERSON IS A HUMAN ORGANISM, A PHYSICAL THING.

STRONG PHYSICALISM: EVERY INDIVIDUAL THING IS A PHYSICAL THING.

PROPERTY PHYSICALISM: EVERY PROPERTY OF ANYTHING IS A PHYSICAL PROPERTY

(A PHYSICAL PROPERTY IS ONE THAT CAN BE POSSESSED BY PHYSICAL THINGS AND ONLY PHYSICAL THINGS)

IS MIND SWAPPING POSSIBLE?

VARIOUS STORIES IN FICTION HAVE PLOTS ACCORDING TO WHICH TWO PEOPLE CAN EXCHANGE BODIES – THE MIND ASSOCIATED WITH ONE BODY BECOMES ASSOCIATED WITH ANOTHER, AND VICE-VERSA.

WHICH PERSON WOULD BE WHICH? IS SUCH A THING REALLY EVEN POSSIBLE? IF A PERSON IS A BODY, HOW CAN IT BE A DIFFERENT BODY? (ALSO THERE ARE STORIES WHEREIN TWO MINDS OCCUPY ONE BODY).

DUALISM

DUALISM IS THE THESIS THAT PERSONS ARE NON-PHYSICAL THINGS (WE IGNORE THEORIES ACCORDING TO WHICH PERSONS ARE “AMALGAMS”: COMPOSED OF PHYSICAL AND NON-PHYSICAL PARTS).

DUALISTS USUALLY MAINTAIN INTERACTIONISM: THERE IS CAUSAL INTERACTION IN BOTH DIRECTIONS BETWEEN A PERSON AND HIS/HER BODY.

INTERACTIONISM HAS PROBLEMS

MANY PHILOSOPHERS HAVE HAD DIFFICULTY SEEING HOW IT IS POSSIBLE FOR A NON-PHYSICAL THING TO CAUSALLY INTERACT WITH A PHYSICAL THING (HOW CAN I, IF I AM A NON-PHYSICAL THING, CAUSE PHYSICAL CHANGES IN MY BODY?)

RENE DESCARTESON INTERACTION

THE SOUL CAN ONLY INTERACT WITH THE BRAIN VIA THE PINEAL GLAND

ARGUMENTS FOR DUALISM

“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.

A LOGICAL PRINCIPLE

THE INDISCERNIBILITY OF IDENTICALS(OR: THE DISTINCTNESS OF

DISCERNIBLES)(DD) FOR ANY PROPERTY F AND ANY

THINGS X AND Y, IF X HAS F AND Y DOES NOT, THEN X IS NOT IDENTICAL WITH Y.

THIS PRINCIPLE DD SEEMS UNIMPEACHABLE

IF X AND Y ARE THE VERY SAME THING (NOT JUST SIMILAR OR EXACTLY ALIKE), THEN ANYTHING THAT IS TRUE OF X IS TRUE OF Y (THAT IS, X).

IN LOGICAL SYSTEMS IT USUALLY IS CALLED “THE SUBSITUTIVITY OF IDENTICALS.”

NEVERTHELESS, THERE SEEMS TO BE SOMETHING WRONG WITH THE

ARGUMENT• COMPARE:• (1) I CAN CONCEIVE OF BATMAN NOT

EXISTING AND AT THE SAME TIME BRUCE WAYNE EXISTING.

• (2) I CANNOT CONCEIVE OF BRUCE WAYNE EXISTING AND AT THE SAME TIME BRUCE WAYNE NOT EXISTING.

THEREFORE:

(3) SO BATMAN HAS A PROPERTY THAT BRUCE WAYNE DOES NOT.

THEREFORE (BY DD)(4) BATMAN IS NOT BRUCE WAYNE.???!!!

VAN INWAGEN’S DIAGNOSIS

ACCORDING TO VAN INWAGEN, THE PROBLEM IS THAT THE PHRASE”

“…CAN BE CONCEIVED BY ME NOT TO EXIST”

DOES NOT EXPRESS (DENOTE, DESIGNATE) A PROPERTY.

A TEST FOR EXPRESSING A PROPERTY

CONSIDER A SENTENCE CONTAINING A PROPER NAME (OR OTHER DESIGNATOR OF AN INDIVIDUAL) AND REPLACE THE NAME BY THE VARIABLE ‘X’.

“OBAMA IS PRESIDENT”“X IS PRESIDENT”“ANDERSON IS A PHILOSOPHER”“X IS A PHILOSOPHER”

CALL THE RESULTING EXPRESSION A “LOGICAL PREDICATE”

THE TEST: A LOGICAL PREDICATE EXPRESSES (DENOTES, SIGNIFIES, CORRESPONDS TO) A PROPERTY ONLY IF THE RESULTS OF REPLACING ‘X’ BY TWO DIFFERENT DESIGNATIONS OF THE SAME INDIVIDUAL ARE BOTH TRUE OR BOTH FALSE.

TRY:“COMMISIONER GORDON KNOWS THAT X IS

BATMAN.”

THE LOGICAL PREDICATE IN DESCARTES’ ARGUMENT

“X CAN BE CONCEIVED BY ME NOT TO EXIST”CONSIDER THE TWO DESIGNATORS:“THE INSTRUCTOR OF PHIL 100E (S 2014)”“I”BOTH OF THESE DESIGNATE ME. BUT THE

LOGICAL PREDICATE FAILS THE TEST. (WHY? A VERY INTERESTING QUESTION. CF. PHILOSOPHY OF LANGUAGE).

A DIFFERENT DIAGNOSIS

THE ARGUMENT DEPENDS ON TAKING “CONCEIVE” IN A PARTICULAR WAY. IN ONE WAY OF TAKING IT, THE LOGICAL PREDICATE MIGHT BE SEEN AS PASSING THE TEST. TAKEN THAT WAY, THOUGH, IT IS DOUBTFUL THAT I CAN REALLY CONCEIVE OF THE INSTRUCTOR OF THIS COURSE AS NOT EXISTING.

A LEIBNIZIAN ARGUMENT AGAINST PHYSICALISM