Systematic Philosophy
Dr. Barbara Gail Montero
The Measure of All
Things?
What does it mean to call oneself a
physicalist? For the purpose of
this
paper, I’m defining physicalism in the following way: “The belief
that
those objects, and only those objects, exist which are can be explained in
terms of (or reduced to) the primitives of modern physics.” Most every strict physicalist will
agree
with this statement (with perhaps some argument over what it means to
“reduce
to” and “explain in terms of”).
There
is, however, a fatal flaw in this formulation of physicalism. Physics cannot help philosophy to
select
a primitive ontology because it does not itself have one definite set of
primitives.
While this may seem a radical
claim, I think
it follows immediately from a complete understanding of the nature and
methods
of modern physics together with a thorough analysis of the provided
definition
of physicalism. Let us begin by
first
examining in detail what is said by the definition provided.
What is a
primitive?
Any formal system[1]
has at least four of classes of objects: primitives, defined terms,
axioms,
and theorems. While the last
three
are easily understood, the notion of a primitive is unusual to those
unaccustomed to formal thought.
The
relation of axiom to theorem is reflected in that of primitive to defined
term. Primitives are those
terms
accepted without formal definitions.
Every formal system has primitives.
It cannot be that all terms are well-defined[2]. In philosophy, the discipline of
ontology
deals with what there is. We can
also
think of ontology as the quest for a set of primitives in terms of which
to
explain the rest of the world. A
few
definitions will make it simpler to speak about ontological physicalism
and its
relation to physics. A general
ontology is a set of objects which are thought to populate the
world. A primitive ontology is the set
of
objects to which the general ontology can be reduced. This reduction often, but not by necessity, takes the form
of constitution;
for example, a table may be constituted out of wood, which is constituted
of
organic molecules, which are constituted of hydrogen, oxygen, nitrogen,
carbon
(and some other atoms), which are constituted of electrons, protons, and
neutrons,
which are constituted out of quarks (and some other particles). If we believe tables exist, they
form a
part of our general ontology.
If
we can offer no explanation of what constitutes[3]
a quark (that is, what a quark is made of) then quarks are part of our
primitive
ontology[4].
A term may very well be primitive
in
one system, but not in another.
In
high-school math, the notion of a natural (counting) number is most often
primitive. However, in set theory
(for
example) the natural numbers are very well defined terms developed at a
high
level of sophistication. Another
analogy is the spectrum of colors.
When
we speak of pigments; red, blue, and yellow are primitive. However, when we deal with optics;
cyan,
magenta, and yellow are used (this analogy lacks the arbitrariness of more
abstract systems).
It is also the case that different
formulations
(or models) of the same system may use different primitives. Quine spoke of this when he proposed a
tribe
that spoke not of rabbits as primitive but rather of unseparated rabbit
parts. However, he did not follow
through with the notion in the context of formal systems. A simpler analogy is perhaps kinship,
where
we may think of Sara as Ellen’s daughter, and Ellen as Nancy’s, or without
loss
of information, we can translate to speak of Sara’s mother Ellen, and
Ellen’s
mother Nancy. Here two different
relations are taken as primitive; in the first, daughterhood, and in the
second, parenthood. For a formal
example, look at geometry. In
Euclid’s
system (as per Elements) he took points to be primitive. In the Egyptian system, distances were
primitive. These do not
define
different geometries[5];
they define different models of the same system in terms of
different
primitives. If Al and Bob (both
philosophers) each present a theory of the universe which has the same
explanatory power as the other, and from which we would predict the same
events, then they are modeling the same system. Physicalism (and other ontological philosophy) has as its
goal
the modeling of the observed universe.
How can we tell if
two
systems are the same?
If we are to speak of different
models
of the same system, and of different systems, we need to know exactly what
is
meant by “system”. Here, I’ll use
the
word “system” to describe a set of observations and truths. That is, in a system, there exists some
set
of rules by use of which we could explain all past events and predict all
future ones, given enough data[6][7]. In this paper, it is my thesis that
physics
cannot provide a unique “correct” model of the universe (which I am
assuming to
be a system). Moreover, I claim
that
alongside physicalism there are other theories that model the same
system. That is, for two ontologies to each be
“correct”, they each model the same system, and that system is the
universe.
What is a
model?
A model of a formal system consists
of
the primitives, definitions in terms of the primitives, and rules
describing
the relation of terms (both primitive and defined) to each other). It’s important to note that primitives
need
not be simply “noun-like” objects, but also that “verb-like” relations and
operations can be primitive. For
example, in set theory, the relation “is an element of” or “belongs to” is
primitive. In grade-school,
addition
and multiplication are primitive, and subtraction and division are defined
therefrom. These are tow examples
of
completely different models that are used for different
purposes.
Different models of the same system may look
quite
different from the outside. For example, for many centuries, the
fields
of algebra and geometry grew separately.
They developed to a high degree of sophistication, each very
different
from the other. However, Descartes
finally realized that they were, in fact, the same thing, and his
synthesis of
analytic geometry permanently changed the face of mathematics. It is my contention that things that
look
very different from physicalism could still model the same universe, and
thus
be just as “correct” a theory.
Physicalism is, at its most basic, a model of the universe. The physicalist claim is that it is the
only
correct such model.
What are some models of the
universe?
In every day practice, we use many
different models of the world around us.
The most common one is the “common sense” system, which takes a
great
deal of primitives. Tables,
chairs,
people, emotions, owning, wanting, creating are all primitive. We are all quite familiar with this
system,
and comfortable with its use, so I’ll not dwell on it. Similar, but slightly more refined is a
Platonic formulation, where there are a large number of noun-like
primitives,
and only one primitive relation “is the essential form of”. All relations between objects are
described
in terms of the relations of their essential forms. Cartesian dualism is another familiar model. In this, there are two rough classes of
primitives, physical and mental.
Most popular among modern philosophers, however, are the
physicialist[8]
models. While these differ in many
respects, at their core, they assert that the primitive ontology of the
universe is the same as that used in physics[9],[10].
How has physics’ ontology
developed, and how does this relate to the development of
physicalism?
Physics’ ontology has undergone any
number of dramatic changes, and the last century has provided some of the
most
sweeping change. In the interest
of
brevity, I’ll provide only a brief sketch of the history of the
field. More information on the history of
physics
is easily obtainable.
Physics as we know it began with
Greek natural
philosophy. While these
philosophies
may seem very different from what we perceive as physics, they were the
first
western philosophies to contain the concept of modeling the world by some
abstract system. This is a key
foundation to what we call science.
Moreover, the Greeks introduced the concept of using “constitution”
as
the fundamental reductive explanation.
This notion is only now being questioned in the scientific
community[11]. There were many competing models, but
the
most important (at least for this discussion) was the archetypal-elemental
model[12]. After the fall of Greece to Rome, the
development of physics/chemistry (the investigation of the nature of
matter)
was postponed. Only the most
dedicated
researchers could find access to the ancient Greek texts, and, as esoteric
knowledge is wont to do, natural philosophy became an occult theory. It wasn’t until the mid 15th
century that science once again become vital, this time shocked into
movement
by the hermetic alchemists. The
alchemists, being researchers of the occult, stumbled time and again into
the
near-forgotten Greek tradition, and completely adopted both the concept of
an
archetypal-element, and the notion of explaining things in terms of their
constituents. Alchemy became the
road
back to classical science. How is
this? Many people believe that the
aim
of alchemy is the transformation of lead to gold. This is a grossly oversimplified view, which in many ways is
completely wrong. Alchemy, at her
most
fundamental, is the attempt to transmogrify the soul from its base
physical
embodyment into a pure and exalted form.
The beliefs associated with this view (that the material is in all
ways
lesser to the non-material) could very well get one labeled as a heretic[13]. This necessitated the development of a
code
to discuss alchemical work.
Drawing on
the archetypal-element theories of Greece (which only the super-educated
and
super-obsessive had access to) a system of correspondences was laid
out. Using the Greek concept of a scientific
model, one could speak of the relation of the model and relate information
about the relations of the modeled system[14]. In this way, alchemy laid the
groundwork of
the scientific method.
The alchemists’ work with the basic metals and
salts, which they carefully manipulated in order to unlock their secrets,
did
not escape the attention of Isaac Newton, the first modern physicist,
himself a
celebrated alchemist[15]. Newton went on to introduce the first
fully
developed set of physical primitives (derived in part from the work of the
alchemists), and was the first to formalize (that is, mathematize)
physics. He proposed a universe
consisting of small, solid masses in constant motion.
His success with this set of primitives led
Dalton[16]
to, in 1803, propose a similar primitive ontology for chemistry. Dalton’s atomic theory was to
lay the
groundwork for all the physics/chemistry to follow, until the 20th
century. Maxwell, in 1873, proposed the addition
of
another set of primitives to science, magnetic and electric forces. A number of important discoveries at
the end
of the 19th century led to the startling conclusion that the
“atom”
was not indivisible.
By the 1920’s physics had recovered, and was
again
approaching a set of primitives.
Bohr
had developed a system explaining the way in which atoms worked in the
inside
(this is the “orbital” theory we still teach in beginning chemistry
classes),
and it seemed that physical chemistry was nearly done. Then came the tempest. A whole horde of particles was found to
constitute the “indivisible” particles inside an atom. With some refinement, it is at this
level
that physical chemistry now resides.
Her primitives are the quarks, leptons, baryons, and mesons. It is very important to realize that
this
standard quantum model derives from the archetypal-alchemical
model. There are now models within physics
which do
not.
So, what’s wrong with using
this
primitive ontology?
There are a number of
problems. Most obvious, is the fact that there is
little reason to believe that we’ve finally “gotten it right”. In all likelihood, new primitives will
come
to replace these, as these “elementary” particles have come to replace
sub-atomics, and atoms and archetype-elements.
Most physicalists, however, will not stake so much on contemporary
physics, however, and reformulate their view as such “Only those objects
are
primitive which are spoken of by a “perfect” physics[17].”
Here there is a subtler flaw, one that requires us to again look formally
at
the notion of a primitive, and at the development of the
standard-model. I spoke before of different models of
the
same system. This is just as real
a
possibility in physics as it is in mathematics. There are a number of other formulations of quantum theory
which
DO NOT take quarks, leptons, baryons, or mesons as primitive. They may seem radically unintuitive, at
first, even in comparison to “standard” quantum formulations, but that is
only
because they do not descend from the alchemical/atomic model. They are not “corrected” versions of
previous particle physics. In many
cases, they evolved out of mathematics or computation theory. These are not less “valid” models
because
they are not “something like our present physics [here the physicalist
seems to
be referring to the standard model of high-energy particle physics as the
entirety of present physics.]”.
One such non alchemical-atomic theory is the
“multiple worlds” theory of David Deutsch.
He proposes that rather than there existing microscopically
indetermined
particles in a macroscopically determined world, there are an infinite
number
of worlds, each determined at the moment of diversion from the other. In his view, every time an electron
decays,
a universe is created for each photon (up or down) that it emits. Before Schroedinger looks in his box,
to see
if the cat is alive or dead, a Schroedinger exists simultaneously in two
different universes -- the “cat dead” universe and the “cat alive”
universe. After he looks, each Schroedinger still
exists in each universe. In one
universe, Schroedinger’s autobiography contains a dead cat, in the other a
live
one. Here the primitives are not
particles, but are bit-states[18].
What does this mean for
ontology?
I can see only two criteria for the evaluation
of
competing primitive ontologies.
First,
is the primitive ontology useful?
That
is, does the set of primitives give us the descriptive power to talk about
all
the things we feel are important to have in a general ontology, including
“inner objects” such as beliefs and emotions?
The second criterion is known as Occam’s razor, and stipulates that
a
smaller primitive ontology (that is, one with fewer primitives) is
better. Any other criteria can be eventually
rephrased in terms of these two.
Consistency, for example, is really a requirement of explanatory
power. Inconsistent models do not
explain things.
If two different models of the same system are
equal in the eyes of these two criteria, then they are both equally
“correct”. It is quite likely that
as
physics continues to evolve, it will take for itself a number of different
primitive ontologies, each useful for different applications. It is just this that has made the
difference
between modern chemistry and modern physics.
Chemistry as a rule uses sub-atomics as primitive, and occasionally
ventures into quarks and mesons, which it explains in terms of them
constituting sub-atomics, and relating to sub-atomics. High-energy particle physics most often
takes the elementary particles (q,l,b,m) as primitive, but is actively
looking
for alternatives. Many branches of
physics use other far “spookier” things -- two-dimensional
“super-strings”,
eleven dimensional god-particles and, completely non-physical wave-form
equations -- as primitive[19]. Each of these models is useful and
correct
in its own right, and they all describe fundamentally the same system
(or,at
least, they attempt to). Physics
does
not have as its concern the establishment of one set of primitives. Such an endeavor would be fruitless and
misguided. Physics establishes a
set of
primitives, and then attempts to describe the world in terms of them. It is not that the Bohr model is
“incorrect”; it is that it models the system on a far more macroscopic
level. The current quantum model is just as
unusable on the large scale as Bohr’s is on the very small.
For philosophy to attempt to envision a
“perfect”
physics is ridiculous. A theory of
physics is not and never can be uniquely perfect. It can perfectly model the world around us, but there is NO
REASON AT ALL that other models could not perfectly model the world in
completely different ways, each stranger and more radical than the
other. Every model of the world requires its
own
set of primitives. We have seen
that
one system of primitives is again and again supplanted by another, more
useable
one. We have also seen multiple
concurrent primitive ontologies, all correct, used to describe different
facets
of the world.
It has been the case over the centuries that
whenever a new primitive ontology came along that introduced a powerful
new way
of talking about the world, a new science sprang up around it. The notion of basing philosophy on the
primitive ontology of a perfect science is, at its core, utterly invalid
because
there is no such thing as the primitve ontology of a perfect
science. A “perfect” science is a
radically plural science, one in which EVERY viable set a primitives can
be
used to explain the world in a huge set of interrelated, interdependent
models[20]. Just as geometry and algebra each give
us a
powerful way to talk about topological relations, yet are completely
different
in ontology and form, so too is it that physics presents us with multiple
models of the same system, each with it own primitive ontology. There is no primitive ontology of a
perfect science, and in just such a way it falls to every physicalist
to
decide whether they really believe there could be one perfect primitive
ontology of the universe.
[1] In this paper, I’m taking “formal system” to be primitive. Any science is considered to be a formal system. Essentially, a formal system is one which contains and is completely consistent with some first order logic.
[2] By well-defined, I mean, not circularly defined, but are defined in terms of other terms, which are well-defined or primitive.
[3] In this explanation I have used constitution as my primary form of reduction. So, while I have outlined a sufficient condition for quarks to be primitive, it is not a necessary one.
[4] This condition is sufficient to make quarks primitive given that they are a part of our general ontology. That is, if we believe in quarks, and are in a system which explains things in terms of their constituents, and we believe tables to be explainable in terms of quarks, and we cannot further explain quarks, then quarks are primitive.
[5] In general, a change in primitives does not produce a new formal system, while a change in axioms does.
[6] For a more formal definition of formal systems, try The excellent World of Mathematics four volume by James Newman (very out of print, but available in most libraries), “The Definition and Nature of Mathematics” (Haskell B. Curry) or “Hilbert’s Program” (quite dated) by George Kreisel. All of these are pre-Goedelian, and therefore a bit out of date, but they provide a good foundation. I am unaware of any decent post-Goedel treatments of the subject appropriate for non-mathematicians.
[7] The assumption that the universe is a system that can be modeled is at the foundation of science. Without it, scientific endeavor is pointless.
[8] The belief that there is only one kind of stuff, and it is “non-spooky”, I’ll call naturalism. I reserve physicalism for a specific kind of naturalism defined in the next sentence.
[9] Some flavors of physicalism assert that the correct primitive ontology of the universe is the same used by a completely correct physics. I’ll deal with this variant as well.
[10] Actually, it may be better to use “physical chemistry” as physics has a great spectrum well outside the interest of establishing a universal primitive ontology.
[11] See the discussion below of Deutsch’s work, for example.
[12] This is the view that all of nature is made of some subset of {Fire, Water, Air, Earth.
[13] And, in fact, led to the entirety of Southern France being placed under interdict during the 4th Crusade.
[14] For example, the metal lead corresponds to the earth, which corresponds to the material. The metal gold corresponds to the sun that models the divine. In this alchemical model, the relation of the divine to the material can be discerned by examining the relation of lead to gold.
[15]See, for example, “A Hypothesis Concerning the Nature of Light”.
[16] Dalton while not an alchemist, was a hermetic kabbalist, and an active member of the Roscrucian Order (an alchemical/goetic magical fraternity).
[17] Another version of this is that the correct ontology is something like the standard quantum model, but corrected. By corrected, it is meant evolved in the same way that the standard model is an evolution of the alchemical/atomic model.
[18] For more on this, see The Fabric of Reality, by Deutsch.
[19] See the later discussion of David Deutsch’s theory, or any solid book on quantum gravitation.
[20] I would venture to say that there are an infinite number of such models, but once we discount isomorphic differences in logics, I can offer no reason why this should be.