Mind and Body
Is Consciousness Reducible to
Brain Activity/Construction?
What is “Reduction”?
It’s always easier to start with examples:
Visually and tactilely, a piece of bread is a
squarish, compressible thing that is edible.
Nutritionally, a piece of bread is a complex of
carbohydrates, minerals, vitamins and so forth,
arranged in a particular molecular structure.
A “reduction” of bread occurs when we
understand that bread just is the molecules
that comprise its structure as a complex of
carbohydrates, etc.
What is “Reduction”?
Another example (Searle’s):
Tactilely, heat is an uncomfortable sensation we
experience in the presence of some things.
Physically, heat is a measure of the kinetic
activity of molecules.
A “reduction” of heat occurs when we
understand that heat just is this kinetic
activity – not some other separate and
different thing produced by this activity.
So, How Can We Define “Reduction”?
It is a process through which we change
our understanding of some thing or
event in reality.
This process entails that we shift from
understanding a thing or event in terms
of one kind of vocabulary to another
kind of vocabulary.
Vocabulary Shifts
“Bolt” is a metaphor that suggests the
independent existence of a visual
phenomenon in addition to the electrical
events that caused it.
First, electrical events; then, a bolt.
But an “electrical event” is just what
lightening is. There is no “first, then.”
Vocabulary Shifts and Reductions
We don’t stop talking about certain
events in “colloquial” language after a
vocabulary shift.
We do understand that such colloquial (or
“folk psychological”) talk is just metaphor
- or short-hand for the more complex
scientific reality.
Reductions and the Mind-Body Problem
The key issue in our essays is whether or
not mental vocabulary is just metaphor for
physical vocabulary.
When we talk about subjective
conscious experiences, are we really
talking about objective physical
events in metaphoric form?
Is Consciousness Reducible to Brain
Activity and Constitution?
Searle:
1.It is “causally” reducible” – there is no
consciousness without brain activity of
the organic sort.
2.It is not “ontologically reducible” – once
caused, consciousness has a nature that
cannot be captured in physical
vocabulary.
Is Consciousness Reducible to Brain
Activity and Constitution?
Churchland:
1.It is both “causally and ontologically
reducible” – so long as we assume that
nascent brain science will follow the
path of most scientific discovery.
2.Searle’s arguments beg the question –
he just asserts that “appearance is
reality.”
Searle’s Basic Points
Something can be causally reducible
without being ontologically reducible.
Example (mine, not Searle’s): the sheer
existence of a human being is causally
reducible to the reproductive
activities/biology of other human beings.
The “reproduced” human being, however,
is not the same as the reproducing human
beings. There is no “ontological” identity.
Searle’s Basic Points - 2
In science, however, most causal
reductions result in ontological reductions
(p. 73).
Example – the appearance of color is
causally reducible to measurable quantities
of light reflectances.
Color just is (is ontologically reducible to)
these quantities; we recognize the visual
experience as “appearance only.”
Causal v. Ontological Reduction
Causal simply means something comes
from something else.
Ontological means that something is
identical to something else.
So what about minds, in this era of
more and more sophisticated
neurophysiology?
Searle’s key claims
Brains cause consciousness. Hence there
is causal reductionism – there would be no
consciousness without brains.
Consciousness is constituted by (“just is”)
the awareness of how things appear;
hence, there cannot be ontological
reductionism (appearance and reality are
distinct) for consciousness.
Appearance is the Reality
“No description of the third-person,
objective, physiological facts would
convey the subjective, first-person
character of (how things look and feel),
simply because the first-person features
are different from the third-person
features.” (p. 74; parentheses mine)
Searle’s Argument Revisited
No ontological reductions (new ways of
understanding what really is) eliminate
appearances.
Appearances themselves have ontological
status – the fact that they persist means
that they have a different kind of reality.
Consciousness just is this reality of
appearances.
Puzzles about Searle’s Argument
The apparent central contradiction:
Ontological irreducibility does entail
that there is no accounting for
consciousness on purely physical terms.
Ontological irreducibility does not entail
ontological dualism.
Churchland’s Critique
Searle is confusing epistemology with
ontology (p. 82).
Epistemology: Something is “known
to John by simply feeling”
Ontology: Therefore, that something
can’t be identical to it’s underlying
physical reality.
Churchland’s Critique Quoted
“Searle is attempting to embrace both
the biologically natural character of
mental states, and their physical
irreducibility. But one or the other of
these has to go.”
(p. 86)
Notes on Intentionality