Re: "Layers of Scientific Understanding" poster
Title: Re: "Layers of Scientific Understanding"
poster
Since the low-resolution preview version of the "Layers"
poster (at <http://www.wonderfest.org/poster/poster.html>) does
not afford a view of the text, it has dawned on me that I had better
make the prose available for inspection.
Accordingly, here are all fifteen paragraphs that grace the
poster's right side. They are grouped in threes according to
their placement in the five major "strata" of scientific
understanding: psychology, biology, chemistry, physics, and the
philosophy of science.
- Tucker
************************ PSYCHOLOGY
**************************
Memetics
Memetics is the emerging social science of meme evolution
through natural selection. A meme (rhymes with
dream) is a unit of culture. It is a piece of information
that passes from mind to mind, and that undergoes mutation, selection,
and replication. Examples of memes are ideas, tunes, styles,
principles, customs, myths, techniques. As Earthlings transfer
biological information via genes, so too do we transfer cultural
information through memes. For example, the idea of
democracy is a relatively fresh-faced meme. It now thrives
in many cultures, mutating slightly as it leaps from mind to mind
across the generations and across national boundaries. Of
course, the democracy meme constantly competes with other ideas of
government for a niche in other cultures, and in ours. No meme
is guaranteed survival.
Evolutionary Psychology
The evolution of life via natural selection implies that behavior has
evolved alongside physiology. Evolutionary psychologists try to
understand behavior by identifying the evolutionary survival
value of various behaviors. For example, affection for
offspring has obvious survival value among primates (humans, apes,
monkeys). Early primates that did not adore their babies would
have allowed more offspring to die during times of environmental
stress. Then fewer primate babies would have reached puberty,
and fewer would have had offspring themselves. For rodents, however,
affection for offspring has less survival value. Since rodent
offspring are plentiful and the length of time they spend in a state
of helplessness is quite short, rodent behavior has not evolved to
include a deep affection for offspring.
Psycho-Neural Identity
PNI theory holds that psychological events (perceptions, thoughts,
feelings, memories, etc.) correspond to brain events. I.e.,
every subjective mental phenomenonfrom the smell of cinnamon to the
meaning of a jokeis a manifestation of neural activity in the
brain. Neuroscientists have not yet identified the precise set
of neuron activities that gives rise to any particular subjective
experience. The so-called neural correlate of the smell
of cinnamon and the neural correlate of your favorite
"knock-knock joke" remain a mystery. Nevertheless, PNI
is supported by tremendous indirect evidence, and is considered to be
the cornerstone of modern neuroscience. Its startling
implications include the assertion that all aspects of
consciousnessthough they may feel very differentare purely
manifestations of neural activity.
************************** BIOLOGY
****************************
Evolution through Natural Selection
Perhaps the most important principle of biologyand the most
momentous idea in science holds that all life on Earth evolved from
simpler forms. Evolution occurs via three steps: variation,
selection, reproduction. Charles Darwin and Alfred Wallace
described natural selection as that fundamentally undirected process
by which the environment "selects" (allows to live and
reproduce) individuals whoby accident of genetic variationhave
favorable gene-borne traits. The idea of evolution through
natural selection enriches and broadens our understanding of life.
In fact, according to eminent biologist Theodosius Dobzhansky,
"Nothing in biology makes sense except in the light of
evolution."
Autopoiesis
The largest unit of life is, arguably, the organism.
(Some biologists say that communities of organismseven the entire
biosphere of Earthcan be alive.) Of course, just defining
"life" is famously difficult. Perhaps the key trait
that distinguishes a living system from any other system is its
ability to derive energy and structure from its environment and
thereby maintain itself. In accord with the laws of
thermodynamics, the energy taken in by an organism equals the energy
removed from its environment. But the structure achieved
with that energy never exceeds the destruction wrought upon the
environment during that energy transfer. Life is messy.
This ability of organisms to create and maintain their structure (at
the greater expense of the their environment) is called
autopoiesis.
Metabolism
The smallest unit of life is the cell. Cells perform two
crucial, life-defining functions: they metabolize (i.e., acquire
energy and matter to maintain themselves) and they reproduce.
Usually, metabolism specifically refers to the creation and/or
manipulation of proteins, the structural building blocks of life.
Physicist Freeman Dyson has proposed that Earth¹s first genuine
lifeforms emerged when self-maintaining, haphazardly-growing
"protein creatures" merged with short-lived,
self-replicating "nucleic acid creatures." The union
of self-maintainer and self-replicator, speculates Dyson, may have
produced the first primitive cell. Biochemists have, so far,
been unable to build such creatures from scratch in the
laboratory.
************************** CHEMISTRY
****************************
DNA Coding
Molecules do amazing things. Some, when in the proper
environment, can even copy themselves. Important examples are
the nucleic acids of heredity, DNA and RNA. Of course, reliable
reproduction is possible only with a reliable mechanism for
information storage. In living systems, these chemical stores of
information are the genes. A gene is a portion of a DNA
molecule that encodes information for the structure of a particular
protein. Proteins, in turn, are the building blocks of cells.
But to understand how the totality of proteins can produce an
individual, we need to know much more than even the total information
content of our genes, i.e. our genome. We need to know
the laws governing the complex self-organizing processes of cells.
The discovery of these laws remains a great ongoing challenge of
biochemistry.
Atomic Theory
Our concept of the atom has come a long way since Democritus
hypothesized the existence of these basic units of matter. We
now know that atoms are themselves composite particles, having an
outer electron "cloud" that surrounds a tiny nucleus of
protons and neutrons. Atoms come in 92 naturally occurring
varieties, the elements, each differing from the others in its
number of protons. The elements¹ ability to combine varies
periodically with the number of protons. The conceptual
organization of elements in the Periodic Table is one of the
crowning achievements of chemistry. Proper understanding of the
Periodic Table allows us to understand how atoms combine to make
molecules and, in turn, how molecules combine to make all of
ordinary matter, from paramecia, to people, to planets.
Statistical Mechanics
Even the simplest atom is remarkably complex. However, we can
often treat atoms as tiny "Newtonian" billiard balls that
obey simple statistical laws when large numbers of atoms interact.
The resulting theory of matter, statistical mechanics,
encompasses two important laws of thermodynamics. The 1st
law amounts to the famous law of energy conservation: the
quantity of energy in an isolated system of particles never
changes. The 2nd law of thermodynamics, in its imprecise form,
says something even more surprising about energy: the quality
of energy in an isolated system always decreases. Potential
energy has the highest quality; thermal energy ("heat") the
lowest. Thus, the 2nd law describes the eventual degradation of
all forms of energy into disordered, random molecular
motion.
************************** PHYSICS
****************************
General Relativity
Gravity dominates the large-scale structure of the universe. Our
prize theory of gravity, called general relativity, describes
gravity not as a force but as the curvature of space. The
overall curvature of space has been decreasing ever since the Big Bang
hurled matter far and wide. Today, we are surprised to see how matter
has coalesced into intricate structures despite this expansion.
On the one hand, the laws of physics explain the formation of
galaxies, stars, and planets quite nicely. On the other hand,
the fundamental constants that must go into those laws to explain
structure seem very improbable. Many astronomers find these
structure-enabling constants so unlikely that they hypothesize a huge
number of other universes in which intricate structures do not
arise!
Classical Mechanics
Everyday objectsfrom the microworld of molecules to the macroworld
of blood, sweat, and tearsobey Newton¹s laws of motion.
These laws describe how masses respond to the forces that act upon
them; they constitute the heart of classical mechanics.
Just two forces dominate our day-to-day activities: familiar
gravity and surprising electromagnetism.
Electromagnetism gives rise to all the forces discussed in chemistry:
ionic bonding, Van der Waals forces, gas pressure, etc. It also
gives rise to all the everyday forces (except gravity) discussed in
physics: friction, contact forces, magnetism, etc. Light is
electromagnetic, as well. Sound and heat are, too, in that they
rely on molecular interactions. Thus, our senses, our muscular
actions, and even our brain activity all rely on electromagnetism for
their ultimate explanation. We are electromagnetic
creatures.
Quantum Mechanics
Many laws of classical physics fail to work in the realm of objects
smaller than about 1 nanometer. This is the realm of
quantaof subatomic particles that obey the strikingly
unintuitive laws of quantum mechanics. Such particles
have only certain precise "quantized" values of physical
traits. This guarantees, for example, that every hydrogen atom
is exactly alike and that the entire Periodic Table is exactly as it
is. But, at the same time, quantum mechanics demands that
quanta not have well-defined traits when in isolation.
Only by interaction with large numbers of other particles do quantum
traits undergo decoherence and gain precise values. The
greatest triumph of quantum mechanics is the Standard Model of
matter and forces. It describes point-like particles, quarks and
leptons, that interact according to the rules of quantum field theory
to make up all of ordinary matter.
************************** PHILOSOPHY
****************************
Experiment
Scientists seek explanations of the things they observe.
The primary attribute of a good explanation is its ability to pass the
test of experiment. Secondary attributes that distinguish good
explanations include coherence, scope, simplicity, and elegance.
Accordingly, scientists ask a great deal of their very best
explanations. Such explanations earn the title theory.
In common, everyday language, a theory may be little more than an
educated guess. In science, however, a theory is as good
as it gets! A theory must agree in detail with experiment,
cohere with all explanations of related phenomena, encompass a broad
range of phenomena, include no unnecessary steps, and, finally,
inspire a subjective sense of beauty.
Reason, Skepticism, & Consensus
Science demands careful reasoning; wishful thinking must yield to
evidence and logical analysis. Every day, we face the temptation
to see what we want to see in nature. Scientists have learned
that a relentless skepticism is the best way to avoid error.
However, at the same time, scientists must be open to the incredible
strangeness and subtlety of the world. A proper combination of
skepticism and open-mindedness is, ideally, the goal of every
scientist. Scientists must also be on the lookout for wholesale
fraud. Fortunately, replication of key experiments and the risk
of censure by the scientific community usually succeed in keeping
scientists honest. Alleged observations become facts only
after a slow, quasi-democratic process takes place among perhaps
thousands of specialists around the world.
Scientific Realism
Science begins with observation.
Virtually every scientist assumes that perceptions, observations, and
experiments pertain to an objective reality that exists outside the
mind of the scientist. Scientific realism holds that the
universe really is a certain way, and that we can come to know
that way through careful observation. Scientific knowledge may
never encompass any aspect of reality perfectly. Further,
science may never come anywhere near ultimate reality.
But scientific models certainly seem to approach ultimate
observable reality, and they do it better and better every day.
Slowly, asymptotically, and sometimes fitfully, science approaches
important truths of the world. And the value of these
models cannot be overstated. Recall the words of Einstein:
"All our science measured against reality, is primitive and
childlikeand yet it is the most precious thing we
have."