Chapter 0: Science and Clear Thinking
The Bennett etal text
"Cosmic Perspective" covers some of the standard material on the
nature of science and scientific thinking, but I have some other interesting
thoughts on this and the larger role of scientific thinking in the discovery
and evaluation of knowledge. Many of you will not have another science course.
So I've put together this personal essay on the subject of clear thinking
in general and scientific method in particular. I hope you enjoy it. A first
rate popular-level book to read on the nature of science, thought, and New-Age
mysticism is "The
Demon Haunted World" by Carl Sagan.
Einstein once said that the most incomprehensible
thing about the universe is that it is comprehensible. It's a great quote,
but it's worth pondering - how did he mean us to take that? I think it's actually
much easier to see why the universe would be comprehensible
1. Natural Selection and
the Development of Mind
The fossil record shows convincingly that
life evolves. Darwin and Wallace showed that this evolution is guided by the
process of natural selection; all members of a species are not born equal.
Some are better able to solve the problems of survival than others. To
Our human ability is the ability to observe
events, abstract from them general principles which appear to govern these
events, and further integrate these principles into wider knowledge in a way
which gives you that "light bulb" feeling of non-contradictory understandng.
Our brains signal errors by giving us that clashing "doesn't fit"
feeling, like when you stare at 2+2=5. Think about that... it's really mental
sensations that signal understanding vs. contradiction. That's getting pretty
organic and pretty biological. Gray matter is doing all this! What makes the
issue confusing to some is that these perceptions and integrations don't happen
without intent and focus. Unlike many other animals, our brains, especially
the reasoning abilities, don't work so well without effort. It takes effort
to make a conscious decision to think, focus, and hold fast to the basic principle
that the desire for truth takes precedence over all other temptations (like,
being proved "right", or impressing someone else, or avoiding a
painful realization, or indulging a questionable desire, or indeed anything
else). Consider... skiing well requires great
focus and effort but pays off with delightful feelings (as long as you don't
hit a tree)
Your brain produces the "light bulb"
feeling when you integrate a new understanding into your previous knowledge
without contradiction. And you get the "doesn't fit" clashing feeling
when you stare at an idea which conflicts with your current knowledge. This
dissonance is your organism's warning signal that you need to focus with greater
attention and clarity to resolve the conflict, that you're not yet in optimal
contact with Reality. And, that "light bulb" feeling of resolution
feels good when understanding finally comes! Its your organism's reward for
doing a good job at integration. Those who spend a lot of time avoiding awareness
by frying their brains on drugs etc don't realize the fun and
pleasure that your feelings give you when you do the right things mentally
(they're also confusing genuine pleasure with trying to numb out pain). We
evolved these feelings as motivation and reward for successfully coping. Ask
yourself how long a species would last if it were wired up to give pleasure
when it acted self-destructively, or didn't give pleasure when it did things
right. Avoiding the "pain" of effort, or of sobering realizations,
is not the same as genuine pleasure, and a continued pattern of avoidance
of mental focus is a guaranteed path to deep anxiety and depression.
2. Using this in
Learning
Wise students will use this fact....look
for the "light bulb" feeling as you learn. If you're not getting
it during lecture, stop me and ask me to clarify what I'm saying in some other
way.
Here's another aspect of learning. Understanding
happens through the manipulation of your perceptions and internal representations
of reality - not of the outside world directly. There are three broad categories
that your internal representations can take: Visual
3. The "Real
World"...
We live in an objective, external world.
In other words, we do not live in some ethereal personal dream/nightmare having
no connection with an external reality. If a person assumes otherwise, then
logically they're at a dead end and, believing their mind to be
Let's pause on the concept of a contradiction.
A contradiction is a statement with two or more ideas which are logically
incompatible. A contradiction is easiest to show in a closed system. A closed
system is a system of knowledge all of whose distinct, independent axioms
are specified, usually because they are defined by us. An open system is one
in which the principles are not defined by us and not necessarily completely
known. Mathematics is an example of
a closed system: For example, once we define the concepts of 2 and 4,
If contradictions do not exist, then there
is no explanatory power provided by the idea of a "supernatural".
There is only that which is real, whether discovered and understood yet or
not. That which is real fits together without contradiction, and that is also
what we
4. Scientific Method
Science is that body of knowledge which is
acquired by the scientific method. OK ... so what does THAT mean? The steps
of the scientific method have been evolved and condensed as the most efficient
way we have discovered for gaining the "light bulb" experience of
understanding, and for ruling out ideas incompatible
with Reality.
All of us, scientists or not, are constantly
making observations. Through your curiosity, eventually you notice a set of
related phenomena and form a question about it. You then brainstorm it, coming
up with any possible explanatory models. These models, at this point, are
called hypotheses. We haven't used any rigorous logic yet, and shouldn't.
This is the time to be as wild and crazy as possible. Maybe you'll have a
good long list at this point. Take your hunch of the best hypothesis and visualize
the meaning of it as clearly as possible, so that you can see what the observable
consequences would be. These observable consequences also need to be objectively
observable, meaning that they need to be visible to others in the outside
world. Then you test your hypothesis by designing an experiment which looks
for these consequences and distinguishes against other consequences. This
is where you have to be hard-headed and logical. If a hypothesis fails a test,
even just one test, then your hypothesis is ruled out. You breathe a sigh
of relief, you've made progress! Now you don't have to worry about that idea
any more. You then go back and brainstorm a new hypothesis. You keep this
circle going until you find a hypothesis which passes all your tests. A
hypothesis which passes all tests so far put to it is called a theory.
At this point, if you're in the science business. You talk to your colleagues
down the hall about your idea. If they can’t pick any holes, you are encouraged
and take your show on the road, giving guest colloquiums and seminars at other
research centers. If your theory’s still standing, you write up a paper for
publication in a peer-reviewed scientific journal. This becomes an open invitation
for other scientists to see if they can devise new ways to test it. The first
thing that is usually done by other scientists, especially if the claim is
important and suprising, is to simply repeat your experiments. If they can't
be repeated, then interest usually fades. But if it passes all tests that
anyone can devise, it may become part of the current paradigm; our "best
current theory". (In actual modern science, most work is done in collaborations,
each contributing their specialized talents to the effort. Still, the sketch
above gets across the real point)
The popular press often presents such a
theory as Final Truth. Scientists are clear in their own minds that their
latest theories are always subject to revision as new observations are made.
The only requirement is that revised theories must agree
This brings up the next point. To stay well
connected to what's real, you have to develop a tolerance for uncertainty.
Those who are too anxious about uncertainty often succumb to taking whatever
idea seems most comfortable, motivated more by the avoidance of anxiety than
the desire for truth. On the other hand, I see the foes of
The game of science is to use your powers
of reasoning and observation to find the most promising ideas of how things
work, and to weed out what doesn't work.
Mistakes will always be made. But the method remains solid, and mistakes
are usually found quickly. This reminds me of another common truth; those
who are too afraid of making mistakes rarely do original, independent, and
ground-breaking work in science or anywhere else.
5. Steps of the
Scientific Method
1. Observations lead to
a…
2. Question, on which
you brainstorm for a…
3. Hypothesis, which you
then get logical and hard-headed about and…
4. Test for Observable
Consequences, which if failed, take you
back to #3, and if passed lead back to #4
over and over until
you run out of do-able tests you can think
of. If it's still standing you have a…
5. Theory!
Few ideas can be said with absolute finality
to be final "Truth", because it's usually impossible to know if
you've exhausted all possible tests. So, what we seek is ways we can rule
something out. For example, consider the Steady State
Now here's two properties of a well formed
scientific theory or
1. It must be falsifiable
- meaning, there must be logical consequences to this theory which, if failing
observational test, rule it out. If all conceivable observations are compatible
with the theory, then the theory is without consequences and without intelligible
content. An idea only has content to the extent that it is distinguished from
other ideas. If there is no distinction, there is no content, even if on the
surface it may appear to be saying something.
2. At least some of its
observable consequences hopefully should be unique. That
means that no other known hypothesis produces the same observables.
From (1), we can hope to
rule it out if it's wrong, and from (2), we can hope, if it's right, to realize
it's a strong, realistic contender, justifying devoting our scarce resources of
time and money in further investigating it.
If your hypothesis has no observable consequences,
then it's is not within the realm of science! If none of your hypotheses have
observable consequences, then the entire question is not within the realm
of science or inquiry. Your hypothesis in this case is called speculation.
For example, the claim that global warming is caused by some kind of unseen
energy waves from a civilization on the planet Krypton circling a star in
a distant galaxy, is not a scientific issue because we do not have the technology
to test the existence of such a civilization there. Which doesn’t mean we
can’t find a sufficient explanation for global warming by looking at testable
ideas instead.
I emphasize that one doesn't need a hypthesis
about HOW an effect occurs in order to test whether it indeed occurs. This
is a common misunderstanding with beginning students in science. A classic
example is given by astrology. Natal astrology claims that your basic personality is influenced by the positions
of the sun, moon and planets at the time of your birth. This is a very testable
claim! It is premature to worry about HOW this influence can happen, and in
fact most astrologers don't try to explain how. The mechanism of the cause
is not important at this point. First test if the claimed association between
birth date/location and personality even exists. If it does, then (and only
then) would it indeed be fascinating to try to discover how this mechanism
works. Some, including our former text author Andrew Fraknoi, go off the rails
and bash astrology because the sun isn't even in the astrological signs claimed.
Well, so what? Since astrologers rarely try and claim a mechanism for why
astrology should work, how can anyone claim the sign offset kills astrology?
It doesn't. What kills astrology is that there is
6. Pseudo-Science
When people use the trappings and jargon of
science to lend an aura of credibility and high-mindedness to an otherwise
bogus body of thought, we call this a pseudo-science. A lot of the New Age
books seen around this town fall into this category. Healing crystals,
As for distinguishing between the "light
bulb" feeling, and the "feelgood" feeling... The "light
bulb" feeling follows from a state of concentrated awareness and desire
for clarity. The "feelgood"'s usually don't. But ultimately, you'll
only know the difference from your personal experience. We are all human and
we all feel the sway of both at times. The wise person observes which is which.
Certainly scientists can get attached to their pet theories as well.
The difference is, if they let their attachment ruin their objectivity, they
lose credibility, can no longer win grants, and other scientists will no longer
take the effort to study their work. The system is stacked against them. It's
the ruthless logic of the scientific method which ultimately disciplines the
field. Good scientists know that they sometimes must witness the "murder
of beautiful theories by ugly facts", as it's humorously been put, and
that in fact their reputation in their field goes up when they themselves
swing the bloody axe. This isn't to say that there aren't wonderful insights
and important advances to our understanding of life and the universe in some
New Age material. Particularly in psychology, I believe academic psychology
is often too simplistic, perhaps in an attempt to be "scientific",
and the important advances have come from out of "left field", or
what seemed like left field when first advanced.
I've always been curious about the motivations
behind the popularity of so much pseudoscience. One motive I've heard is the
feeling that scientists take all the magic out of life, reducing it to cold
statistics. But consider the incredible discoveries of the last decade in
my own field of astronomy. The astronomers I know will, every one, tell you
their own experience is that, in the words of Jules Verne, "Reality provides us with facts so romantic that imagination
itself could add nothing to them”.
7. General Principles in
the Design of a Scientific Test
Astronomy is a bit unusual in that there's
rarely a chance to set up situations and do full-bore scientific testing like I
describe below. But for most of you, these ideas below will be important to
consider in, for example, evaluating the truth of medical claims. Something we
all are exposed to.... Suppose you are to design an experiment to test the
claim that taking beta carotene supplements will reduce the incidence of cancer
(to take a currently publicized example). Here's some guidelines...
You'll want to get a sample of people and
give half of them beta carotene and half a placebo. A placebo, in this case,
would be a pill that looks like a beta carotene pill but is in fact some inert
ingredient already shown to be unrelated to cancer. Here's some
a. The placebo effect. The mind powerfully affects the body. Our thoughts and feelings
affect health in ways we only are beginning to understand. If someone believes
beta carotene works, and they take a pill they think is beta carotene, they may
in fact induce poorly understood internal processes which may in fact lower
their probability of getting cancer. More commonly, expectation has a huge
effect on the perception of pain. Even "physical" pain has a large
psychological component. Pain, after all, is our bodies signal to our
conscience mind to "do something - we're in danger". Once you
believed you've done something useful (like taking a pill you believe will
help, even if it is actually just a sugar pill), then your perceived pain can
drop noticeably. This is why illnesses whose only symptoms are subjective
perceptions (e.g. chronic fatigue syndrome) require very careful science in
order to evaluate properly. Both of these aspects are called the placebo
effect. To guard against mistakenly assuming the healing was caused by beta
carotene, you must be sure that not only does the subject not know which pill
has beta carotene, but neither does the person giving him the pills. If the
doctor knows he's giving placebos to one group and real pills to another, some
subtle mannerisms may betray this. A study done this way is called a
"double blind" study.
b. Proper controls. A controlled study is a study where great care is taken to insure
that any other factors which could conceivably affect the outcome are identified,
the subjects are classified according to these factors, and other subjects
with these same factors are given placebo's. You're then essentially doing
a separate test on each sub-categorized sample. For example, suppose the cancers
you're testing occur in women more than men. If you don't separately record
the gender of each subject and properly match the test subjects with the placebo
subjects, then you could mistakenly infer an effect due to beta carotene which
is in fact due to gender differences.
c. Sufficient sample size. There may be many causes
for cancer. Our hypothesis is only that beta carotene will reduce cancer incidence,
not eliminate it. If Aunt Mabel takes her beta carotene every day and lives
to age 100 before she dies of kidney failure, this is NOT
d. Random sample
selection. You must be sure your
sample is random with respect to what you're measuring. You wouldn't want to go
to the cancer ward at the local hospital to find your volunteers. Neither would
you want to go to an alternative medicine conference - you'll likely get an
exaggerated placebo effect.
e. Sufficient time. Run the test as long as you believe the effect could take to
appear. For cancer, we know it may take many years from cause to malignancy.
f. "Associated"
does not necessarily mean "caused". This one is really unappreciated by the popular press. You may assume
one thing caused another, when in fact both things are caused by a third.
Suppose you do a study and find with high statistical significance
g. Don't overinterpret
the data. This one is another
pit-fall lurking in alternative medical claims. For example, it can be tempting
to look at, say, a medical practice which provides symptom relief and assume
this provides support for an entire paradigm which includes this practice. Yet
the medical practice itself may have no logically necessary relation to the
paradigm. Consider a native American practice of grinding and eating willow
tree bark to banish the evil spirits showing themselves as what we’d call
inflamation and pain. And you find with good scientific tests that this willow
tree bark really does lead to pain relief far beyond that predicted by random
chance after controlling for placebo etc. Does this provide support for the
evil spirit paradigm? No, it only provides support that this willow bark can
relieve pain. Maybe it's the salacylic acid (a.k.a aspirin!) which is found in
willow bark which is the active ingredient.
8. Occam's Razor
This is a principle in science named after
Lord William of Occam. We've noticed over and over that, given two or more
theories, all of which explain the observations, the one which ultimately
will most likely pass the tests is the one which requires the least changes
to current thinking. In other words, "simpler is usually truer".
Perhaps the ultimate reason that this seems to be true is that our brains
really are evolved to work well at understanding nature. The converse is that
"extraordinary claims require extraordinary evidence" (a famous
quote of Carl Sagan). Occam's Razor is what chops down the UFO sightings.
99%+ of UFO sightings can be explained more simply as e.g. the planet Venus
twinkling through turbulent air, or large meteors or military aircraft, ball
lightening, wishful thinking, etc.... if not out-right hoaxes. The alien abductee
stories can be more simply explained as attention- (or money-) getting frauds, or self-induced hypnosis. Also,
the relaying of the story from source to eventual publication often gets subtly
(or not so subtly) distorted.... The old "fish story" phenomenon.
To be a bit more charitable, most people
don't appreciate how much our expectations influence how they "see"
what they see. Too often we see what we expect to see. Go to the Exploratorium
in San Francisco, or the Mystery Spot up in the mountains here to see this
in action. The brain so much wants to make sense out of what it perceives
that if that person has no prior category for the sensory input, it'll force
it into a category more familiar (even if only from the National Enquirer).
Magicians use this to their advantage. Most people don't understand how differential
refraction causes bright objects like Venus or Sirius to rapidly twinkle through
many colors, so they think they're seeing flashing lights of an alien spaceship
(since everybody's seen airplanes do this). I and other astronomers I know
will be quite happily amazed and delighted if someone proves indeed that aliens
have or are visiting Earth. Till then, I'll keep my hand on my wallet.
On that sobering note....learn to drop the
scales from your eyes and take a fresh look at the universe. The moral of
all this? Practice "safe concluding" - be careful about what beliefs
you allow to be uncritically thrust into your brain. And hold onto your wallet!