"The highest object at which the natural sciences are constrained to aim, but which they will never reach, is the determination of the forces which are present in nature,and of the state of matter at any given moment - in one word, the reduction of all the phenomena of nature to mechanics."  Gustav Robert Kirchkoff, 1865.

"Reductionism" is a concept that either angers people or delights them.  The entire enterprise of Science is based upon a belief in reductionist tenets.  Although the idea is at least 2500 years old, it remains unpalatable to at least 95% of the population.  Curiously, only 40% of scientists object to the basic tenets of reductionism.

Reductionism claims that the Universe somewhat resembles an immense 3-dimensional billiard table, in which, to a first approximation, all movements are mechanical - having been set in motion by the explosive birth of the universe 13 billion years ago!  The following explanation of reductionism is an essential starting point for the rest of this book.

A Rigid Universe

"The Universe Rigid" was possibly H. G. Well's most important manuscript.  It languished with the publisher, who didn't understand it, and eventually it was lost.  Instead of reconstructing it, Wells turned its central idea into a story, The Time Machine (1895).

Two dozen years later, Albert Einsten published his Special Theory of Relativity, which, for most people, introduced the idea of time as a fourth dimension.  However, Pierre-Simon Laplace had described the universe in similar terms nearly a century earlier, and this may be where Wells got the idea for "The Rigid Universe" - which appears in brief form in The Time Machine:

 "... Suppose you knew fully the position and the properties  of every particle of matter ...  in the universe at any particular moment of time:  ... Well, that knowledge would involve the knowledge of the condition of things at the previous moment, and at the moment before that, and so on.  If you knew and perceived the present perfectly, you would perceive therein the whole of the past.  ...  Similarly, if you grasped the whole of the present, ... you would see clearly all the future.  To an omniscent observer ... he would see, as it were, a Rigid Universe filling space and time - a Universe in which things were always the same.  He would see one sole unchanging series of cause and effect...  If ‘past' meant anything, it would mean looking in a certain direction; while ‘future' meant looking the opposite way.  From the absolute point of view the universe is a perfectly rigid unalterable apparatus, entirely predestinate, entirely complete and finished ... time is merely a dimension, quite analogous  to the three dimensions of space."

This passage describes the underlying principle of what is referred to in today's parlance as "reductionism."  It leaves no room for spirits, mysticism or gods.  Most people use the term "reductionism" as a disparaging epithet, but I believe it is the crowning achievement of human thought.

Historical Perspective

Reductionism is the fulfillment of what Democritus and Lucretius dreamed about, a world-view that could deliver people from the tyranny of religion.  "There is no need for the aid of the gods, there is not even room for their interference. ... Man's actions are no exception to the universal law, free-will is but a delusion."  (Bailey, 1926).

The 19th Century saw a de-mystification of various science disciplines.  The reshaping was done by rationalists, who firmly placed the fields on a footing that has endured throughout the 20th Century.  Like the machines of 19th Century inventors, the paradigm assembled by 19th Century scientists was "mechanistic."

Darwin allowed God to be removed from the process of evolution.  Ernst Mach forced metaphysics out of physics (Gerald Holton, Science and Anti-Science, 1993).   And chemistry was changed from a floundering quest for transmuting common elements to gold, into a physics-based understanding of atoms and molecules.

By the end of the 19th Century, when Wells began his writings, the intellectual atmosphere was congenial with ideas that reduced mysterious happenings to a juxtaposition of commonplace physical events.  Each event, in isolation, was conceptually simple.  It is the mere combining of many such events that cause things to appear incomprehensible.

Reductionism as a Basis for Physics

Reductionism is based on a concept taught in college Physics 101, which I took as a freshman.  Without fanfare, the student learns that there are only four forces in nature (gravity, electro-magnetism, the nuclear force and the weak force), and a finite number of particles (approximately a dozen) that are pulled this way and that by the summation of all forces acting upon the particle.  [In 1979 Steven Weinberg, Abdus Salam and Sheldon Glashow received the Nobel Prize in Physics for their contribution to a theory of the unified weak and electromagnetic interaction between elementary particles, which implies that the weak force is actually a "leakage" of the electromagnetic force.  Experimentalists have validated a prediction from this theory, so if it continues to be verified we should really speak about there being only 3 forces in nature.  I notice that it is still common practice to refer to "the 4 forces" of nature, and I have adhered to that convention for the remainder of this discussion.]  In laboratory experiments, where the forces can be controlled (i.e., where only 1 or 2 forces are important), and where the particles can be restricted to simple configurations, motions are governed by a simple law: F = ma, or "force equals mass times acceleration."  It is easier to understand this law of nature by rewriting it in the form: a = F/m, which states that a particle's acceleration is given by the sum of forces acting on it divided by the particle's mass.  (Mathematically, a and F are vectors, which is why those symbols are written in "bold" typeface, and "m" is a scalar; thus, the a = F/m equation keeps track of the 3-dimenssional direction of force orientations and accelerations).  Since forces can originate from many sources, they must be added together to yield one net force.

At every instant, the particle is responding to just one net force.  It responds by accelerating in the direction of that force (which has a magnitude and direction).  The particle's velocity changes due to the acceleration.  Since the time history of a particle's velocity specifies where it goes, the particle's "behavior" is completely determined by the forces acting upon it.

Whenever an experiment is set up that enables the forces upon a particle to be evaluated, the particle's movement is observed to obey a = F/m.  This is true when the particle is a simple subatomic particle, like an electron or proton, and also when the particle is more complicated, like an atom, molecule or group of molecules.  There is every reason to believe that a = F/m is true for ever more complicated arrangements of particles, since any configuration of particles can be viewed as a system of many simple configurations - for which we have confidence that a = F/m applies.

It can be argued that the physicist exhibits "faith" in extending what is observably true in simple settings to more complicated ones.  This assertion of faith is true, but the faith follows from the physicist's desire to invoke a minimum of assumptions for any explanation.  Adopting a = F/m for simple situations is an assumption, and extending it to more and more complicated situations is an additional assumption; but this path to explanations is a "minimum assumption" path, and it has survived every challenge.

Imagine a game of billiards photographed from above and consider one shot redisplayed in slow motion.  After the cue sends one ball into motion, the entirety of subsequent impacts and bounces are determined.  If this were not so, if the balls had a mind of their own, or if some mysterious outside force intervened, then consistently good players would not exist.  Now imagine a very slow replay of the motions of the billiard balls; millisecond by millisecond the movements unfold with an undeniable inevitableness.  A careful analysis would reveal that a = F/m governs the placement and velocity of each ball in the next millisecond.  Given two successive "frames," a physicist would know the positions and velocities of every ball, and he could calculate their placement, impacts and velocities for any arbitrarily short instant later.  He could thus predict the following frame, and the process that allowed the prediction of frame 3 from frames 1 and 2 could be repeated for frames 2 and 3 to predict frame 4.  And so on, for all future frames.  In this way, the physicist could predict all future movements (we've ignored friction, which causes the balls to slow down and eventually to come to rest, but this is merely another force which is less straightforward to deal with, and should not subtract from the analogy).

By a similar process the physicist could infer a previous frame from any two neighboring frames.  Thus, frames 1 and 2 could be used to predict frame 0, etc.  Therefore, by knowing any two frames, all future and past frames could be inferred.  This is the thought H. G. Wells expressed with his unpublished Universe Rigid essay.

Now imagine a frictionless table of thousands of bee-bee sized billiard balls.  It can have walls (and it can even be a 3-dimensional enclosure).  The same concept can be applied: with two closely-spaced "photos" (3-D photos) that specify the location of all bee-bees, a following or preceding location of all bee-bees can be inferred.  And, all future and all past locations can eventually be determined.  This imaginary example brings us closer to the real world.  The "ideal gas law" is a 3-D box of very small balls that bounce off each other and bounce off the walls, causing a "pressure" force upon every wall area.

The larger the number of balls, i.e., the larger the number of atmospheric molecules that are represented, the more accurately can the wall pressure be represented by the famous physical chemistry equation, called the "ideal gas law": PV = nRT, or the wall pressure times enclosure volume equals the number of molecules (actually, the number of "moles" of molecules) times the Rydberg constant times the "temperature" of the gas.  The ideal gas law equation can be derived in a straight-forward manner using a=F/m.  The point of this example is to show that there's a bridge between a simple world in which a = F/m is the most useful deterministic principle to a more complex world in which a "law" derivable from a = F/m is more useful.  When PV=nRT is used by the physical chemist, or meteorologist, he is nevertheless acknowledging that a = F/m governs motions at the microscopic level.

It is common for scientists to rely upon "laws" that in principle can be derived from a = F/m but which are simply more convenient to employ.  The existence of a "higher" level in a heirarchy of scientific laws does not invalidate the ultimate determination of motions by the a = F/m at the lowest level.  This is most important to remember when considering scientific findings that pertain to living things.

Living Things Are Subject to Physical Laws

Living things are made up of the same electrons, protons, etc that constitute inanimate things.  A reductionist assumes that electrons and protons found in animate objects are moved by natural forces in accordance with the same a = F/m  law that applies to electrons and protons found in inanimate objects.

This is a profound assertion!  If a person's brain is made up of electrons and protons that obey a = F/m, then the brain is a "mechanism."  It changes state in accordance with the same basic laws of nature that control a machine.  The brain is immensely complicated, and masks the fundamental simplicity of what is happening inside; the particles within are moved by the same forces that move simple systems; and it is moved by no other forces!

If this is true, then "free will" must be an illusion.  Or, as Schopenhauer has written, "A man can surely do what he wills to do, but he cannot determine what he wills."  However, by carefully defining "free will" it should be  possible to rescue the essential idea of free will from reductionism; I will do this in a later chapter.

The reductionist way of thinking does not come naturally, and even the physicist cannot always remain thinking at this "level of thought" - especially in daily life.  Complicated problems are more efficiently viewed using "concepts" that are in theory derivable from a = F/m.  The perfect gas law PV=nRT is a straightforward example of this.  Although it is referred to as the perfect gas law, it is really not a basic law of nature, as it can be derived from a = F/m as an approximation to the properties of a large number of molecules.  It is a more useful "law" since there is no practical way of knowing the positions and velocities of each particle that comprise a volume of gas, which would be a precondition for invoking a = F/m; yet every chemist would acknowledge that a = F/m is fundamentally what's happening when PV=nRT is used.

Likewise, the neuropsychologist must formulate "laws" more pertinent to the aggregate behaviors of neural networks, and may conveniently forget that a = F/m is actually controlling brain function.  It may be useful to occasionally employ chemistry and electricity concepts to understand brain function, but this is probably the neuropsychologist's most extreme downward reach in the heirarchy of conceptual explanations.  Nevertheless, the neuropsychologist should acknowledge that the concepts he finds useful are shorthand summaries of what is theoretically deriveable from a = F/m.

Taking a more extreme example, any attempt to understand the rise and fall of civilizations will not find much guidance from a = F/m, as the causes and effects are too remotely related to the myriad interactions of electrons and protons.  It is better to employ concepts such as social parasitism and climate change, for example, than a = F/m.

Acceptance of Reductionism is Difficult

The brain evolved, like every other organ, to enhance survival of the genes that encode for its assembly.  It should be no surprise, therefore, to find that it is an imperfect instrument for comprehending reality.  If it is more efficient to deal with interpersonal matters using concepts such as jealousy and anger, rather than the concept F=ma, then the brain will be "designed" for employing these higher heirachy concepts.  Since few tasks pertaining to survival require the a = F/m way of thinking, the brain will find this to be a difficult concept. It is a triumph of physics to have discovered that a = F/m rules everything!

Reductionism, then, is the belief that everything can be "reduced" to simpler systems obeying laws that are more basic in the heirarchy of concepts; and that the ultimate level for explanation is the simple a = F/m mechanistic realm of physics.  A person believing in reductionism does not advocate that a = F/m concepts be employed in all situations.  This would be a ridiculous position, because it is horrendously impractical!  The reductionist, like anyone else, will employ concepts appropriate for the level of complexity of the task at hand.  Complex configurations of particles require the use of concepts high in the conceptual heirarchy.

What, then, is the point of reductionism?

A reductionist would reject suggestions that are incompatible with reductionism.  This sounds straightforward, but it has a subtle meaning.  Entire categories of "explanations" fail to satisfy the reductionist requirement.  To say that the wind is the action of the "wind spirit" is simply a non-explanation.  Not only does it call for an explanation of what the wind spirit is, and how it came to be, etc, it is totally unnecessary.  There will always be a simpler explanation, such as "a high pressure system is located to our north and the air is flowing away from it, toward a neighboring low pressure region."  This explanation, in its turn, can theoretically be simplified by invoking PV=nRT, which in turn can be simplified even further by invoking a = F/m!  Thus, the reductionist can, in theory, "reduce" a phenomenon high in the conceptual heirarchy to those at the lowest level in the heirarchy.

It is important to understand that if a person "choses" to remain at the most basic level of physical explanation, where only a = F/m explanations can be invoked, then the concepts of P, V, n, R and T, for example, are superfluous, and while remaining at this level the concepts don't exist!  But if a person choses to view the world at a next higher level, he will invoke PV=nRT, define the terms (pressure is the force per unit area per unit time caused by momentum change of particles bouncing off a surface, temperature is the average kinetic energy of the population of particles, etc), and proceed without explicit use of a = F/m.  A meteorologist will want to go one level higher and make use of pressure gradients, coriolis force (a fictitious force that makes things easier to work with), eddy diffusion coefficients, etc.  For him, there is no explicit use of a = F/m, nor of PV=nRT.  A climate change scientist may go one step higher, and make no explicit use for any of the lower level concepts.  Notice that whichever level is chosen, all concepts at higher levels are redundant, and non-existent (for as long as thought remains at the one level).

Whereas I chose examples in the atmospheric sciences, the concepts apply to all other sciences.  In the life sciences, for example, a next higher level might be that of the molecular biologist.  He works with strands of long molecules called RNA and DNA, etc.  It is useful to think of these long molecules as consisting of sequences of the nucleotides thymine, cystosine, adenine, guanine and uracil.  Laws at this level specify that cytosine only pairs with guanine (and visa versa) in forming a DNA molecule, etc.  No explicit use is made of a = F/m, but notice also that the molecuar biologist has no use for such concepts as "consciousness" or "free will."  These and other higher level concepts are redundent, and don't exist, while remaining at the molecular biology level of understanding living phenomena.

At an even higher level in the life sciences, consider the neuropsychologist.  He wants to know where nerve cells in the brain connect, and which hormones are released by a gland when activated by a specific nerve signal, etc.  He does not make explicit use of a = F/m, or DNA, or most other molecular biology concepts.  For the neuropsychologist, such concepts as "free will" and "consciousness" seem forever appealing yet elusive.  This is because free will and consciousness are concepts that belong to a higher level, psychology.  The neuropsychologist should not invoke these higher level concepts to give an account of phenomena observed at the neuropsychology level.  If he tries to invoke them, he is attempting to bridge levels, and I believe this is an impossible task.

I do not object to the use of higher level concepts, since they are more useful for most tasks.  However, a scientist must always be aware that these many levels exist, and he should be prepared to view a problem from the next lower level, or even the next higher level, if the problem seems intractable.

A naieve person might believe that the primitive, who views everything in terms of spirits, thinks at a higher level than the scientist.  This would be a ludicrous belief.  A primitive is a lazy and unsophisticated thinker.  He is totally oblivious to reductionist "levels of thought."  As I will describe later, he uses a brain part that is incapable of thinking rationally:  the right pre-frontal cortex.  Human evolution's latest, and possibly most magnificent achievement, is the left pre-frontal cortex, which is supposed to usurp functions from the right pre-frontal cortex when rational thought is required.

A fuller exposition of this topic cannot be given without a background of material that will be presented in later chapters.  For now, I will merely state that mysticism is a natural way of thought for primitive humans.  It is "easier" for them to invoke a "wind spirit" explanation than explanations based upon a = F/m, or higher level physical concepts.  They do this without realizing how many ad hoc assumptions they are creating, which themselves require explanations that are never attempted.  Their thinking may seem acceptable from the standpoint of a right pre-frontal cortex (or "efficient" from the perspective of the genes that merely want to create a brain that facilitates the gene's "goal" of existing in the future), but it is terribly inefficient for the thinker endowed with a functioning left pre-frontal cortex demanding rational explanations that minimize assumptions.  This unthinking proliferation of ad hoc assumptions bothers the reductionist, but not the unsophisticated primitive.

At the risk of offending an unsuspecting reader, I shall claim that God is another primitive attempt at explanation!  A "believer" is not bothered by the fact that their "solution" is really an even more formidable "problem" that itself requires an impossible explanation.  People who ignore this problem are guilty of an over-reliance upon their primitive right pre-frontal cortex.  Again, this topic can only be pursued after more groundwork has been developed, which is the task of chapters 4 through 10.

H. G. Wells must have understood the issues raised in this chapter.  The reductionist paradigm was an important part of intellectual thought one century ago, and Wells grasped it more surely than even many scientists today.  He realized that at the most fundamental level, if a particle's position (and velocity) were known at one instant of time, and if the other particles in the universe had known positions, then the "F" in a = F/m could be calculated, and the particle's new velocity (prior velocity, and modified by the acceleration "a" term in the equation) could be calculated, and its movement during the next instant of time could be calculated.  And if this were true for the first instant, it was just as true for the second, allowing prediction of the particle's position at a third instant; and so on, forever.  The present has inherent in it the entirety of the future.  Going backward in time could be achieved by merely changing a sign, using a = - F/m.  Thus, the present inherently includes the configuration of the universe for all time, both past and future.  Such a universe is "rigid" and time is just a fourth dimension!

Reductionism is for the Few

Scientists, engineers and inventors must have been held in high esteem during the second half of the 19th Century, and the first half of the 20th.  The per capita number of significant discoveries and innovations, as measured by Asimov's "Chronology of Science and Discovery" (Asimov, 198X) peaked at about the middle of this period (actually, 1910 AD, derivation available upon request).  Reductionist ideas were at least understood by literary people, and even accepted by some.  Novelist Theodore Dreiser wrote "I have pondered and even demanded of cosmic energy to know Why.  But now I am told by the physicist as well as the biologist that there can be no Why but only a How, since to know How disposes finally of any possible Why."  (Dreiser, 1931).

Sadly, we cannot expect today's intellectuals to have the same profound understanding of the nature of reality as was exhibited a couple generations ago by such writers and social commentators as Wells and Dreiser.
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