The argument from neural
dependency
• A natural consequence of dualism should
be that the mind itself is not damaged
whenever the brain is damaged.
• A natural consequence of materialism is
that when the brain is changed, the mind
of the person is also changed
• Empirical neuroscience supports the belief
that changes in the physical brain affects
also the mind.
Dualistic response
• Dualism does not imply that mental states
are not dependent on brain states. It only
says they are distinct from those states.
• Mental states can causally depend on
physical states (states of the brain) while
still being distinct from those brain states.
What is it like to be a Bat?
Suppose you knew everything there was to
know about bat physiology
Would this knowledge give you also
knowledge of what it is like for the bat to
be a bat (E.G. would it tell you what is like
to perceive the world through
echolocation.
Intentionality
• A common feature of mental states is that
they are about something other than
themselves. If I am thinking, I am thinking
of something—a horse, a dog, the moon..
• But physical states do not exhibit this
“aboutness” or intentionality.
• Therefore, materialism is false (b/c it fails
to explain the intentional character of
mental states.
• Nagle: no it would not
• But if materialism is true, then complete
knowledge of bat physiology should give
us also complete knowledge of everything
about a bat—including the bat’s conscious
states
• Therefore, a materialistic theory of the
universe leaves out a crucial feature of the
universe, subjective experiences.
Another knowledge argument
Suppose that Mary is a brilliant physiologist who
has studied color perception extensively. She
knows all that can be known about the
physiology of color perception.
But she has also lived her entire life in a
completely black and white room.
When she leaves the room and experiences color
for the first time, does she experience something
new?
• If she does, then there is something left
out of the material description of the
human organism (what she learns in her
black and white room)—the qualitative
character of the experience, what it is like
to see something blue or purple.