Transcript "Meat Thinks" Talk Notes

Meat Thinks
Sandra LaFave, Ph. D.
Until a few hundred years ago, philosophers,
especially rationalist philosophers,
considered it IMPOSSIBLE that
bodies (“meat”) could think. One obvious
reason is that souls in heaven are typically
portrayed as doing all kinds of conscious
stuff – thinking, sensing, enjoying, etc. –
while their bodies are obviously decaying.
René Descartes (1596-1650), for example,
did not think physical stuff could think.
His view is known as substance dualism.
Substance dualism is a metaphysical view: a
view about what exists, has being, is real.
It is also a view about what it means to
be a person (“personhood”).
According to substance dualism, only two kinds
of things exist:
• physical things (res extensa) and
• non-physical “things” (res cogitans).
A person comprises both kinds of being,
although the body is temporary and disposable.
According to substance dualism, the
two kinds of being are completely
different.
Their properties are incompatible.
See the handout for substance
dualism’s descriptions of the
properties of the two basic
metaphysical categories.
Note that “XOR” means exclusive OR.
The logic expression “p XOR q” means
that either p or q is the case but NOT
BOTH.
What's distinctive about Descartes’ substance
dualism is the notion that Mental (capital “M”)
substance (res cogitans) is necessary for
mental states.
We would probably want to say the brain is
involved somehow, no? Descartes denies this.
If something is Mental, it can’t also be physical.
If something is physical, it can’t also be Mental.
The Mental comprises all “invisible” events of
consciousness including thoughts, intentions,
desires, knowledge, and feelings.
Only res cogitans can think, feel, and know.
To sum up, according to the metaphysics of
substance dualism, everything that exists is either
• Res cogitans: thinking “substance”
(rational, unlimited, dispassionate, orderly,
logical, clean, “pure”, free, active, creative mind
or soul or consciousness) – “soul”;
XOR
• Res extensa: extended substance (inert,
passive, corruptible, possibly disgusting,
predictable, decaying) – body.
Note how the material/physical column
describes the attributes of things in the world
as described by science. Things and events
in the physical world are able to be sensed,
occur regularly, and can be predicted on
the basis of scientific laws.
Res extensa, for Descartes, is the world of
determinism.
If persons were merely material things, they
would be objects in the universe and their
movements in the world would be determined
by the laws of science.
They would not have free will.
But free will is a fundamental Christian doctrine.
The notion of free will underlies the notion of
sin. No sin, no need for redemption from sin,
no need for Jesus.
Substance dualism – the idea that reality
includes material and non-material – also
has implications for epistemology.
Epistemology is the branch of philosophy
that concerns knowledge.
What can res cogitans know with certainty?
Only propositions like itself: propositions whose
truth is independent of res extensa. For example,
math truths are true whether or not res
extensa exists. So is cogito ergo sum.
Knowledge about res extensa is knowledge
about the changing world of the senses, so in
that sense, knowledge about the external
world has to be inferior and unreliable.
Knowledge about the realm of res cogitans is
unchanging and universal, and thus absolutely
reliable. This kind of knowledge is often called
a priori knowledge, like knowledge of math
and logic.
Why substance dualism is attractive
1. It includes human freedom.
2. It makes humans and other rational
beings unique and special – superior to mere
things, able to use and command things.
(Remember the Church condemned Galileo for daring to say the Earth
was not the center of the universe.)
3. Res cogitans can survive the dissolution
and death of res extensa, so people survive
death. As Plato put it, “The soul of man is immortal and imperishable.”
Descartes’ project in the Meditations
The full title of the work?
Meditations on First Philosophy
in which are demonstrated the existence of
God and the distinction between
the human soul and body
Descartes wrote the Meditations to satisfy
the Church that it had nothing to fear from
the new science.
So Descartes is careful not to challenge ideas
important to the Church, such as free will
and the existence of immortal souls.
In fact, he gives arguments for those views.
At the time Descartes was writing, scientists had
already found what seemed to be (and was)
very reliable knowledge about res externa,
particularly in astronomy.
Scientists, including Descartes, wanted the
Church not to persecute them, and hopefully,
to accept that science has an important role
to play in the world.
The Church, for its part, wanted scientists not
to interfere in its role as the ultimate moral
authority. Science per se didn’t threaten the
Church as long as science talked only about res
extensa: in other words, as long as science kept
silent about conscience or religious or moral belief.
Descartes found a clever way of reconciling the
Church to science. He noted that if God is not
a deceiver, the objects of math knowledge appear
to be unchanging universals, so if God is not a
deceiver, res cogitans knows math with
absolute certainty.
However, math was also the language of science.
But the scientists’ mathematical (a priori)
knowledge of the world was drawn from
unreliable changing sense data
-- i.e., from res extensa.
Descartes wants to show that math knowledge
about res extensa is really reliable (Descartes’
own work on optics was on the line), without
scaring or offending the Church.
Does anyone know Descartes’ solution?
HINT: it’s in the title of the Meditations.
Meditations on First Philosophy
in which are demonstrated the existence of
God and the distinction between
the human soul and body
Descartes’ strategy may strike you as lame,
but here it is:
(1) Demonstrate in a way that convinces any
rational person (even scientists) that God exists
and is not a deceiver. Descartes uses a
traditional argument for God (the Ontological
Argument) that supposedly does not involve any
reference to res externa. This is a whole other talk. Let’s
just note that philosophers have a lot of issues with the Ontological Argument.
(2) Recommend to the Church that because God
exists and is not a deceiver, scientists should not be
prevented from using math confidently in their
investigations of the physical world. Whether they
know it or not, scientists depend on God for the
legitimacy of their conclusions about the external
world.
Furthermore, since res cogitans cannot be
an object of scientific study – since it is still private
and unobservable – scientists can have nothing
to say about it.
Science rules in the realm of the physical.
The Church rules in the realm of the spiritual.
Interestingly, the Catholic Church has pretty
much stayed out of science’s way since
Descartes, so his strategy worked.
Too bad substance dualism has so many
problems.
Philosophical Arguments Against
Substance Dualism
Objection 1:
The most obvious problem is that substance
dualism appears to fly in the facts of our
ordinary experience of our bodies and our
consciousness (res cogitans).
If mind and body are completely separate
kinds of being, why does consciousness
change when I put LSD into my body?
Why do people with brain damage (e.g.,
people with Alzheimer’s disease) have any
loss of normal consciousness?
Objection 1 exemplifies what philosophers
call the mind-body problem.
If substance dualism is true, the two
kinds of reality are totally sealed off from
each other: res extensa can’t influence
res cogitans, and res cogitans can’t influence
res extensa. Yet as we have seen, the two
kinds of being appear to interact all the time.
How do you move your arm, for example?
You might say that first you think about moving
your arm. Your res cogitans does the thinking,
according to substance dualism. Now, res
cogitans is not part of the physical world. And
things in the physical world move only by the
agency of other things in the physical world.
So how exactly does your thought of moving
your arm result in your arm moving?
Descartes knew, of course, that there was
interaction between mind and body.
Descartes says, “I [presumably his res cogitans]
am not only lodged in my body as a pilot in a
vessel, but … I am very closely united to it, and
so to speak so intermingled with it that I seem
to compose with it one whole.”
Examples:
If I hit my hand with a hammer, I am
conscious of pain (body influences mind).
I feel the pain of the hammer immediately,
without having to call in res cogitans.
If I remember that my Mom’s birthday
is today, I will pick up the phone and
call her (mind influences body).
Descartes needs to explain how this is
possible.
His response is disappointing, though.
In Passions of the Soul, he writes
“I had clearly ascertained that the part of the body in
which the soul exercises its functions immediately is in
nowise the heart, nor the whole of the brain, but
merely the most inward of all its parts, to wit, a certain
very small gland which is situated in the middle of its
substance …” (the pineal gland, in the mid-brain)
Wait a minute … didn’t he say mind can’t be located?
Descartes’ “solution”: the pineal gland is the
“locus of interaction” where the mental can
interact with the physical.
Malebranche’s “solution”: Although God is
res cogitans, God can do anything, including
move bodies. So you might think you’re
moving your arm, but it’s really God.
Neither of these solutions are adequate.
Objection 2: The Mental is defined only in
terms of what it is not.
Generally, negative definitions are far too
vague to be useful.
How many zillion things are contained in the set
of “not-pencils”?
Objection 3: The notion of res cogitans is
compatible with all states of affairs.
If a claim is compatible with all states of
affairs, the claim can’t be proved true or false.
Consider the following statements:
(1) “Sandy LaFave is in this room.”
(2) “Barack Obama is in this room.”
(3) “God is in this room.”
Statement (1) is true, because it corresponds to
what is so.
Statement (2) is false, because it does not
correspond to what is so. We know how the
room would be different if Obama were here.
Statement (3) is neither, because we don’t know
how to determine whether the state of affairs
expressed is the case. We don’t know how the
room would be different if God were here
(assuming the ordinary notion of God as an
invisible being).
Scientists are wary of statements that can’t be
proved true or false.
You find statements compatible with all states
of affairs in astrology and pseudo-science.
Examples:
(1) “The universe came into being this morning,
complete with so-called “historical” records
and so-called “memories”.”
(2) Your horoscope of the day: e.g.,
“You may be disappointed today.”
The claim that “res cogitans exists” is similar.
The very definition of res cogitans
guarantees that you won’t be able to tell
if it’s around, since it’s supposedly unable
to be sensed by bodily organs, invisible,
outside of space and time, etc.
Objection 4: Substance dualism commits the
fallacy of composition.
What’s true of the parts isn’t necessarily true
of the whole.
Consider this fallacious argument:
All the atoms comprising this desk are mostly
empty space.
Therefore, this desk isn’t solid at all; it’s
mostly empty space.
The argument is fallacious because the arguer
assumes (wrongly) that whatever is true of
the parts of the desk (the atoms) must be
true of the desk.
BUT …
The parts of a thing often have quite different
properties from the whole thing.
A whole thing often has different properties
from its parts.
Another example of the fallacy:
The Philosophy Club is more than 30 years old.
Therefore, every member of the club is more
than 30 years old.
(True premise, false conclusion = bad logic)
Another (important) example:
No cell of the body is conscious.
Therefore, no body is conscious.
The conclusion here does not follow from the
premise.
Objection 5: We don’t need res cogitans
to explain consciousness and mental events.
Consciousness is an emergent property of
brains. Mental events are brain events.
Wetness is an emergent property of water.
Consciousness is an emergent property of
brains.
Ockham’s razor says
“Do not multiply entities unnecessarily.”
So if the notion of res cogitans is so problematic
-- it gives rise to the mind-body problem,
its existence can’t be verified or falsified, it
is defined only by negation, it is not needed
to explain consciousness, etc., -- then
according to Ockham’s razor, we should
probably remove res cogitans from our
metaphysics. Translation: give up the idea of spiritual substance.
Substance dualism also contributes to confusion
and unsavory consequences in two other ways:
(1) In epistemology, substance dualism helps
contribute to serious misunderstandings of
subjectivity and objectivity.
(2) Substance dualism supports traditional
misogyny and speciesism.
(1) In epistemology, substance dualism helps
contribute to serious misunderstandings of
subjectivity and objectivity.
Substance dualism has contributed to the
mistaken idea that “Objective” and “Subjective”
are mutually exclusive (the XOR).
In science, “OBJECTIVE” goes with “public”
“physical” “measurable”. “SUBJECTIVE” goes
with “private” “mental” “not measurable”.
Epistemologically for rationalists like
Descartes and Plato, what happens “inside” the
private conscious self (feelings, emotions,
intentions, thoughts) is forever private, since
everything is either res extensa or res cogitans
and never both. No one can ever feel your pain,
for example.
And epistemologically, the notion of “opinion”
– subject to change and improvement – goes
with res extensa: the changing world of the body
and the senses.
So, if you have a headache, according to
substance dualism, your headache is
an experience of res cogitans (consciousness),
so it is “subjective” “invisible” “private” and
in fact cannot be known to exist in the physical
world, because there are only two mutually
exclusive ways to be in the world: either
res extensa XOR res cogitans (and not both).
This is odd, no? We do think headaches are
felt AND are also events in the physical world.
People go to doctors every day for pain relief.
It can get odder.
You might apply this very same reasoning to
your experience of the Eiffel Tower. There you
are in Paris, looking at the Eiffel Tower, and
you think, "Gee, no one else is having this
precise experience of the Eiffel Tower, it’s my
private experience, so this experience of mine
is just as subjective as my headache!“
And if you are philosophically inclined (and
philosophically naïve), you might go further and make
an argument like this:
P1: All my experiences of res extensa (the world) are
unique and private to me, i.e., they are all “subjective”.
P2: “Subjective” is the XOR opposite of “objective”.
P3: If all my experiences are subjective, then whatever
I say about them has to be mere belief or opinion.
P4: P1 and P3 are true of everyone!
C: Nobody can be objective about res extensa.
Anything anyone says is “just their opinion”.
But (as Plato liked to argue), not all opinions
are equally valuable. Some people’s opinions
are nonsense.
(2) Substance dualism helps support traditional
misogyny and speciesism.
Terry Bisson’s story
They’re Made of Meat
The aliens in the story are OK with the idea
that meat can think.
“The brain does the thinking. The meat.”
In fact, most contemporary philosophers
would agree with the aliens.
So if the issue is not substance dualism, what
is it?
Historically (and even today in many cultures)
people have denigrated the body, sexuality,
and bodily pleasure because the body is
supposedly the dirty disposable inferior part
of a real person, and a major source of
temptation to sin.
Furthermore, cultures commonly identify
the mind with the Male (he is rational,
active, objective, logical, strong-willed) and
the body with the Female (she is emotional,
passionate, weak-willed, passive, and in
need of the guidance of the man).
Western cultures have historically withheld
personhood from many people.
Females have not had the status of full persons
in many cultures.
The same goes for lower-status men.
Western cultures still withhold personhood from
big-brained social animals (chimps, dolphins,
elephants, whales, etc.) and Artificial Intelligences
(AIs).
Since we do not know what extraterrestrial life
forms might look like, humans will need to think
carefully about which alien life forms should be
treated as persons and which are
expendable/edible.
Since in substance dualism, the res cogitans is
the real person, identifying res cogitans with
the Male in effect denies genuine personhood
to females, lower-status men, children, bigbrained social animals, and AIs.
Descartes, for example, thought animals did
not have consciousness.
And because substance dualism’s has only two
mutually exclusive metaphysical categories, not
a full person means not a person at all.
Many entities are consigned to the status of
Other, permanently and with no appeal.
And if you are Other – res extensa – you are
just a thing. You are made to serve the highstatus Male, who can use you with impunity.
You might even be a source of disgust, like …
meat.
The aliens represent the dilemma facing humans
qua res cogitans in encountering unusual life forms
(e.g., aliens and AIs): how to decide who counts as
worthy of respect, and who is Other. And
unfortunately, the aliens in the story handle this
human dilemma in a typically clumsy human way:
arbitrarily, irrationally. The aliens think humans are
meat, meat thinks, and meat is simply disgusting.
Notice their disgust is not based on reasons; it is
visceral and primitive. The aliens know that mere
disgust is not a good enough reason to ignore the
signals, yet they decide to ignore the signals anyway,
and thereby violate their own official rules.
They demonstrate, for me, the ambivalence towards
the “lower” body/Other that has historically gone
hand in hand with substance dualism.
This ambivalence towards Others – those whose
full personhood is in question – seems to me
a prominent theme in popular culture. For
example, story lines about ETs and AIs are
commonplace, and a recurring theme
is “You can’t deny respect and rights to [fill in
the blank] just because [fill in the blank] is from
another planet, or happens to be a sentient
robot.”
The world of Star Wars has that problem licked.