Scientific Reductions

OHear: Chap. 8

Inherent Generality of Scientific Explanations

Treat seemingly disparate phenomena as all of a type

the tides
the motions of planets
the behavior of projectiles and freely falling bodies

by bringing them under the cover of generalizations or scientific laws

universal generalizations: For every action there is an equal and opposite reaction.
statistical generalizations:

the half-life of U-235 is 64 years.
90% of African-Americans who vote vote Democratic.

increasing breadth of explanation

comes about through the formulation & confirmation of ever more general laws
one way in which science may progress

Atomistic Reductionistic Tendency of Science

Proceed by analysis of macro-level phenomena

into their parts
and their relations

The Unity of Science Picture

social phenomena to be explained in terms of -- and so reduce to

individuals
and their relations

the behavior of individuals to be explained in terms of

their biological parts: ultimately cells
and their relations

cellular phenomena to be explained in terms of

molecules
and their interactions

molecular phenomena to be explained in terms of

atoms
and their interactions

atomic phenomena to be explained in terms of

subatomic particles
and their interactions.

Increasing depth of explanation
Reductive insofar as it seems to be saying

societies are nothing but organizations of people
people are nothing but physical organisms, i.e. organizations of cells
cells are nothing but organizations of molecules
molecules are nothing but organizations of atoms
atoms are nothing but organizations of subatomic particles

Materialistic or physicalistic tendency

the fundamental level of explanation or existence
through which everything else is described/explained or constituted/caused
is the most basic material or physical level

Reductions in the Physical Sciences

Popper: Reductions can fail without being failures

Example: the failure of Logicism

Logicism: the attempt to derive all of mathematics from logic + the intuitive notion of a set
rocks that sank it

paradoxes of intuitive set theory:

Russell's paradoxes

the class of all classes that are not members of themselves
is it a member of itself

attempts to get round this paradox seem required unintuitive modifications

various different axiomatizations of set theory
Russell's theory of type

Göedel's Incompleteness Result

showed that every mathematico-logical system
at least as complex as ordinary arithmetic
will contain true statements which are not provable within the system
undercutting the logicist hope of reducing

mathematical truth
to deducibility with a logical system

Things achieved through it's failed reductive attempt

Göedel's Incompleteness theorem itself a seminal result of 20th Century mathematics
axiomatization of set theory a hugely fruitful mathematical achievement
the theoretical foundations for digital computation

derive from the mathematician Alan Turing's attempt to worked out a minimal basis from which everything calculable could be calculated
Turing imagined very simple devices . . . since called "Turing machines"

read symbols from a tape
write symbols to a tape
move one square in either direction

and proved that anything calculable could be calculated by such a device

Case 2: the failure of Pythagoreanism

Pythagorus held that everything was reducible to natural (i.e. whole) numbers
but the length of the diagonal of a square with a side = 1 was the rock on which it crashed

this (= the square root of 2) proves to be
not expressible as a ratio of any two natural numbers
legend as it that the Pythagorean who discovered this

committed suicide
was killed by his fellow Pythagoreans

nevertheless the Pythagorean legacy is a rich one

atomism: the ur atomic theory of Democritus drew heavily on Pythagorean ideas
scientific ideal of quantitative description and mathematical characterization

Modern History of Physical Scientific Reduction: Physics Proper

Newton's reduction of Kepler's laws of Planetary motion & Gallileo's laws of Terrestrial motion

to one set of laws

gravitation
three laws of motion

a staggering gain in breadth
perhaps not so much in depth:

"the forces postulated by Kepler and Galilleo are not being broken down into simpler components" (p.181)
at any rate, perhaps not in any straightforward way

Cartesian mechanics -- Descartes' program -- was more reductively ambitious

Dualism

parcel off the mind -- inner space or conscious experiences
minds -- or thinking substances -- are something spiritual and apart from the world

Mechanism

All else -- the whole natural world -- is nothing but matter: extended substance

matter

completely fills space (nature abhors a vacuum)
and is continuous not particulate (else you'd have empty spaces between the particles)

essential characteristics of matter

extended: takes up -- or better, makes up -- space
from which it excludes every other portion of matter

Motion

consists of portions of matter exchanging place
is caused only by direct contact, by pushes

no final causation by inwardly conceived aims or backwardly causal ends
no action at a distance

Newton's success exploded Cartesian reductionist dream

Newton postulated absolute (including empty) space
and gravitational action at a distance
and his views were coherent with and gave impetus to the corpuscular (or atomic) hypothesis

Newtonian/Atomic reductionist aspirations ran afoul of the inability of physicists to account for electricity and magnetism in Newtonian terms
Einstein's proposal: it all reduces then to

gravitation forces -- which constitute space
and electromagnetic forces -- which constitute matter which is made up of

protons: having/being positive charges
electrons: having/being negative charges

hope for unified field theory to unite the two

Einsteinean proposal & hope sunk by

discovery of other subatomic particles: neutrons & positrons (for starters)
irreducible nuclear forces

the strong force
the weak force

The reputed reduction of chemistry to quantum mechanics

Bohr's quantum theory of atomic structure

predicted the chemical properties of known elements
and the existence and properties of the element Hafnium, which was later discovered

And may also explain (though Popper disputes this)

the nature of chemical bonding
certain features of the periodic table of the elements

Still not a proper reduction Popper argues because

theory requires heavier elements to be built up from hydrogen
to helium and so on by fusion
and we have to appeal outside of quantum mechanics

to cosmology & cosmogony
to complete the explanation of how the present elements formed

So it's not a reduction of chemistry just to quantum mechanics
So higher level properties -- the ironiness of iron, for instance

are emergent properties
i.e., not predictable just from constituent parts and the laws of their operation
but rather unforeseeable apart from the very specific conditions which gave rise to it
emergent in a weak sense

predictable under these conditions
from the their lower level constituents and the laws of their interaction (i.e. quantum mechanics)
but oy vey! . . . who could predict such conditions

the Big Bang a unique event
how could there be laws of or generalizations about or expectations concerning the occurrence of a unique event?

Emergent properties

characterized

properties of wholes which are not properties of their parts
and not explicable in terms of -- i.e., predictable on the basis of -- the interactions of the parts

emergent properties are outliers: beyond the pale of our would-be unified story
candidate emergent properties

life

vitalism
now widely accepted that the life processes

respiration
reproduction
etc.

are fully explicable in biophysical terms
vitalism is dead

mind . . . especially consciousness or subjective experience

property dualism (compare & contrast Cartesian substance dualism)
mind/consciousness

emerges from physical processes (in the brain, presumably)
but totally inexplicably/unpredictably

might be able to correlate some brain events with some experienced experiences
but can't say why this should be so

why one would expect something like this to happen -- the light of subjective conscious experience goes on
as a result certain chemical and electrical changes in and interactions between neurons

this is -- and will ever remain, many say -- an unaccountable mystery

Criteria for Reduction

Talking reduction

Ps are (really just) Qs

identify claim
metaphysical claim: that Qs are more basic

metaphysically: their Yish properties cause their Xish ones
epistemologically: their Yish properties cause their Xish ones
materialism/physicalism

part causes whole, not vice versa: causation is material, not formal
past causes future: causation is efficient, not final

atomism: the parts are discrete units

example reduction: genes = DNA molecules

Concerning the general nature of the reductive identity claim

not identity of meaning

in contrast to definitional identities, e.g., "kitties are cats" and "flapjacks are pancakes"
"gene" doesn't mean the same as "DNA molecule"

"gene" means "fundamental hereditary unit":

to be a gene is to play a certain functional role
defined by the place of "gene" in Mendelian genetic theory

"DNA" means "deoxyribonucleic acid":

to be DNA is to have a certain chemical structure
that the name itself describes

reducing identities are nondefinitional

they are discovered in nature
not stipulated as matters of linguistic convention
it's was an empirical discovery that DNA plays the role assigned to genes in Mendelian genetics

Three levels of reductive identification (in order of increasing strength)

extensional equivalence: the bare minimum
classical reduction: derivation of laws: the impossible dream
species specific or case by case: physicalism's last stand

Extensional equivalence: the bare minimum

basics: extensional equivalence is just co-occurence or invariable correlation

Quine's example: renate (having kidneys) and cordate (having a heart)

every renate is also a cordate & vice versa
though the properties are quite different
Accidental? Could have been otherwise?

Classical example: human and featherless biped

every featherless biped is a human and vice versa
though the properties are quite different
it's accidental: could have been otherwise

extremely accidental example: the coins I just showed you are the coins in my pocket

every coin in my pocket is a coin I just showed you and vice versa
though the properties are quite different
it's accidental: could have been otherwise

our example

discovered that when we find things behaving as the Mendelian genetics describes genes
we find DNA molecules
we conclude that Mendelian genes are DNA molecules

discussion: extensional equivalence the first hurdle

so far so good, with genes & DNA
but something more seems required

in no way do we think that being a coin you've just seen
reduces to or is the same thing as being a coin in my pocket

but we think that being a gene

does somehow reduce to or come to the same thing as being a DNA molecule
despite the fact that "gene" and "DNA" molecule don't mean the same thing

Classical Reduction: Derivation of Higher Level from Lower Level Laws

Overview

"gene"

is a term of a higher level theory: genetics
whose meaning is determined by its place in that theory

"DNA"

is a term of a lower level theory: biochemistry
whose meaning is determined by its place in that theory

Hope for a more robust identification (than mere extensional equivalence)

if we can derive/explain the laws of genetics from the laws of biochemistry
we will have shown that genes behave as they do (according to the laws of genetics)
because DNA behaves as it does (according to the laws chemistry)
which to show how DNA is uniquely suited to play the gene role

DNA doesn't just happen to be what genes are
DNA is what genes have to be
in order to function as they do

Nagelian reduction schema

for every higher order law: (x)(H1x -> H2x)
there is some lower level law (x)(L1x -> L2x)
and some bridge principles (x)(L1x <-> H1x) & (x)(L2x <-> H2x)
from which the Higher order law is derivable

(x)(L1x -> L2x)
(x)(L1x <-> H1x)
(x)(L2x <-> H2x)
:. (x)(H1x -> H2x)
example

H1: "experiencing a pain that smarts"
H2: "wincing"
L1: "such & such pyramidal cell activity"
L2: "such & such facial muscle movement"

Trouble with classical reductions

merely correlational character of the bridge laws

the correlation -- together with the lower level laws -- explains why smarting pain causes wincing
but it doesn't explain why pain feels that way just correlates

a certain kind of pyramidal cell activity
with it feeling that way

failure of lower level laws to track the higher level

lower level categories or types may not correspond nicely to higher level typology

e.g., what's recessivity amount to at a molecular level?
simple regularities at the higher level might result from complicated rigamaroles down under
so metaphysical economy of reduction might come with a high epistemological cost

perhaps due to multiple realization: demand for bi-conditional bridge laws too strong

there's more than one way to skin a cat: i.e. to do accomplish a function or do some job
speculative example: something besides DNA

could be capable of playing the role Mendelian theory assigns genes
and actually play that role (in Martians, say) . . . call it XYZ

then genes wouldn't be DNA

they'd be DNA (in us terrestrials)
and XYZ (in those extraterrestrial)

multiple realization & species specific or case-by-case reduction

what MR is

the same high level property
being realized differently in different species
or even different individuals
or even in different instances in the same individual

to see MR really exists, consider the square peg and the round hole

consider the property of being a 1" square peg

different lattice structures of chemically different molecules
will constitute being a 1" square peg
in different materials: wood, vinyl, iron, etc.

the higher level law: "A square peg 1" on a side can't fit in a round 1" diameter hole"

captures a comprehensive regularity
that is lost in the diversity of different explanations as to

why such and such a wood lattice structure won't go into such and such another
why such and such a vinyl lattice structure won't go into such and such another
and so on

deeper levels of explanation turn out to be less comprehensive & unifying

example airfoils

boat sails, solar sails, airplane wings, bird wings
behavior unified at relatively high level by the laws of aerodynamics
despite the widely different material realizations of aerodynamic features e.g., shape

An epistemological setback: no unified explanation at the lower level
Not necessarily a metaphysical setback

so long as each (type) or square peg or airfoil
behaves as it does, in accordance with the high level theory
because of it's particular lower level constitution

Supervenience

"good" example: two naturally identical strawberries, one good, one bad
(x)(Lx -> Hx): conditional realization laws

says every DNA molecule will behave genetically so
doesn't require that only DNA molecules do so

materialism saved

in each case the high level phenomena is caused or determined
by the lower level phenomena
in accordance with the realization law
in this way emergent properties are anchored in their physical bases

the curvature of the airfoil despite being something different in different type airfoils
is still something physical in each different airfoil

corollary: no upper level difference without a lower level difference

physical duplicates (individuals having identical physical properties)
will be total duplicates (identical in all their properties)

Psychology

"What remains if I subtract the fact my arm went up from the fact that I raised my arm?" (Wittgenstein, Philosophical Investigations, Sect.621)

In the physical case the realization relation is numerical identity

this mass of solid ice just is this lattice structure of molecules
this volume of liquid water just is those same molecules rolling about
and the intervening heating process just is the intervening k-energy increasing process

Psychological application

my intending to raise my arm just is some (as yet) unknown neural event(s)
my raising my arm just is these firings, flexings, etc.
and the intervening thought processes just are whatever their neurological correlates are

Reluctance to say the same in the mental-physical case

beliefs, desires, and intentions don't introspectively seem like electro-chemical processes
introspection reveals them as they are

subjective experiences
not objective occurrences

so, beliefs, desires, and intentions aren't electrochemical processes
subjective properties and events (property realizations) are emergent
salve for materialism: treat realization as a causal relation: property v. substance dualism

Problem: Overdermination

single physical event: my arm goes up
caused by two separate chains of events

a chain of subjective mental experiences
a chain of objective electro-chemical occurrences

unsimple &

wildly implausible, at best
contrary to plausible metaphysical principle: every event has just one cause

mental causation problem

the causal-realization on the right goes in the wrong direction
my arm went up because I raised it, not vice versa

interruption problem

if the physical chain were interrupted
the mental chain should raise my arm all by itself

if EACH mental event is physically caused: PARALLELIST/EPIPHENOMENALIST

solves the interruption problem
residual overdetermination problem for mental events . . .
mental causation problem remains: still not my wish, belief, and intent that makes my arm go up

Would-be solution to the overdetermination problem: EPIPHENOMENALISM

solves the overdetermination problem & interruption problem
mental causation problem aggravated:

mental mental causation eliminated also
my wish + belief can't even cause me to form the intent to raise my arm much less raise it

Would-be solution to the mental causation problem: INTERACTIONISM

intermittent
solves the mental causation problem
solves the overdetermination problem
raises problem of causal closure of the physical

every physical event that has a cause -- every macro-event -- has a physical cause

if this were true
then physics would have to invoke psychological concepts to explain certain physical events: e.g.,

efferent nervous impulses
leading to muscle flexing
leading to my arm going up

would-be implication: when humans act voluntarily exceptions to the ordinary laws of physics occur

leaves out the physical causal links that we have good reasons to think exist between the underlying bodily states

Would-be solution to the causal closure problem: SUPPLEMENTED INTERACTIONISM

reinstates overdetermination
reinstates interruption potential

Token identity solution

realization is/involves (token) identification
each mental property instantiation is at the same time an instantiation of the realizing physical properties
m=b; m1=b1; m2=b2
comparison one and the same event might be

my first faux pas of the evening
a spilling of red wine on the white carpet
note: it's true to say my first faux pas of the evening caused a stain on the carpet

assessment

solves the interruption problem
solves the overdetermination problem
partially solves the mental causation problem: residual epiphenomenalism

mental is only causal by courtesy . . . so to speak
just as my first faux pas of the evening stained the carpet

because it was a wine spilling
not because it was a faux pas

similarly my intention to raise my arm

because it was an electro-chemical occurrence in my brain
not because it was a certain subjective experience

Intentional-mental states (thoughts) vs. Qualetative states (raw feels or pure experiences)

intentional mental states: thoughts: propositional attitudes

beliefs, desires, decisions, etc.
are about things: their intentionality

example: italicized = the intentional object of my belief

I want to demonstrate a point.
I believe that raising my arm will do so.
I decide to raise my arm.

peculiarity: opacity of the intentional relation

possible nonexistence of the object: failure of existential generalization
aspectuality: failure of substitutivity

Oedipus wanted to marry the Queen of Thebes
The Queen of Thebes was his mother.
Yet Oedipus didn't want to marry his mother.

compared to ordinary transparent relations

Oedipus married the Queen of Thebes
The Queen of Thebes was his mother
:. Oedipus married his mother.

potential reducibility

experiential content variable or nonexistent

e.g., your belief that zebras don't wear leisure suits in the wild
e.g., the belief that the sun will rise tomorrow when

tomorrow's the day your bride's gonna come
tomorrow's just another day
you're going to be executed at dawn

attitudes construable as functional states: defined in terms of the roles they play in some mechanism or process

an decision to raise my your is a state caused by

wanting something
& believing it would be best obtained by raising your arm

and causing

efferent nervous impulses that (normally) lead to
muscle flexings that (normally) result in
ones arm rising

comparison: functional reduction: characterize role: discover the player of the role: identify

just as "gene" picks out a functional role player defined by Mendelian genetic theory

DNA being the player of the gene role (in us)
we can say genes are DNA: identity

"decides" picks out a functional role player defined by (folk) psychology

such and such a neurological process being the player of that role (in us)
we can say deciding (in us) is that neurological process

qualia: pain is a pain

but consider the would be functional reduction of pain

a state caused by

bodily damage or
states incipient to damage

causing in turn

flight
learning: future avoidance: "the burt child fears the fire"

would be identification

pyramidal cell activation plays that role
so pain is pyramidal cell activation

Why not?: residual epiphenomenalism revisited

maybe o.k. it's not the experience of deciding but the decision electro-chemistry that makes my arm go up

due to the thinness of the experience
approaching zero -- perhaps obtaining it -- in the case of unconscious attitudes

repressed desires
latent beliefs: e.g., about the zebras and their leisure suits

less o.k. in the case of pain

the hurtfulness is the pain
experience of the pain = the pain itself: no unconscious pains
and it had better be the painfulness of it that make me withdraw my hand