Background
Information-The Nature of Science
“The
whole of science is nothing more than a refinement of everyday
thinking.”
—Albert Einstein, 1936 in Physics and Reality
Overview
What
is science? Unfortunately, most people think of science as a collection
of facts, a body of knowledge. This is, however, only the “end”
product of science, it is the knowledge that the process of science
has acquired. Furthermore, non-scientists often perceive science
to be a collection of immutable, unchanging facts. The passive
mass media (television programs, advertisements, and movies) tend to
reinforce this perception, promoting science illiteracy. When a new
study reports that scientists have “changed their minds,”
have overturned a previously held fact or idea, people tend to distrust
science. Ironically, these types of events are actually the real advances
in our understanding. They illustrate the true nature of science (as
tentative and self-correcting), as well as the real power of science
as a way of knowing.
Goals
and Assumptions of Science
So,
what is science? Let us start by asking, what are the goals of science?
Science, at its most basic level, is a search for explanations about
the natural world. The goal of science is to find the best possible
natural explanations for natural occurrences. Scientists seek to understand
why the natural world is the way that it is, as well as how the natural
world works. In order to do this, they use methodological
naturalism1 . Methodological naturalism is a philosophical
rule used by scientists. This rule states that scientists must look
for a naturalistic cause (and only a naturalistic cause) for a natural
phenomenon. In other words, scientists cannot invoke supernatural
explanations2 . This method of science assumes:
1)
The natural world has an order to it—nature follows the same
general rules throughout the universe
2) Natural phenomena have natural explanations
3) Humans can uncover these explanations, using critical and
objective thinking, as well as careful investigation
Why
do scientists use this methodology? Because it works! It has proven
to be a reliable method of uncovering explanations for natural phenomena.
The Nature of Science
Science
is a self-correcting process that produces reliable, objective public
knowledge. Scientists are not super-human. The ideal of the objective
unbiased scientist uncovering the “truth” is a myth. Everybody
has different experiences, values and biases, and scientists are no
exception. Why then should we accept what scientists have to say? The
reason is that even though individual scientists are not perfectly objective
and they do make mistakes, other scientists will eventually uncover
those mistakes. Any result of importance will almost immediately be
re-tested by other scientists. Eventually, any mistake or error produced
by individual subjectivity will be found and overturned. Consensus
is the basis for scientific knowledge. Scientific knowledge is
not based on one person’s “say-so;” it is based on
the collective consensus of many scientists working on the same problem.
This is the power of science as a way of producing reliable, objective
public knowledge.
This is also why all claims in science are viewed as tentative.
There is no such thing as proof in science. Unfortunately, advertisers
commonly promote this misconception by erroneously claiming that “science
has proven” their product to be better than others, or to be able
to cure whatever ails you. The reality is that every claim a scientist
makes is tentative; it may eventually be overturned by new evidence
in the future. Of course, there are varying degrees of tentative, depending
on how well supported by evidence the claim is.
A scientific fact is a well-confirmed observation. It is a
claim for which there is so much evidence that it is unlikely to be
overturned. In practice, facts are claims that are no longer actively
tested; they are taken as given. But the fact is, facts are not immutable.
Scientists must remain open to the possibility that established facts
may turn out to not be true. For example, it was once a fact that humans
had 48 chromosomes. The available evidence at the time supported this
fact. Now, it is a fact that humans have 46 chromosomes. New evidence
(made possible by new technology, etc.) overturned the earlier fact,
and replaced it with a newer (but still tentative) fact.
Similarly, hypotheses are also tentative. A scientific hypothesis is
a possible explanation for an observed phenomenon. Hypotheses are tested
and re-tested with new observations and experiments. They are consequently
rejected, supported and/or modified. Hypotheses are never proven.
On the contrary, scientific knowledge advances by the systematic rejection
of available hypotheses. Basically, the hypothesis left standing “wins.”
But, since it is always possible that the true explanation may not have
been included in the list of available hypotheses that were tested,
even a well supported, non-rejected hypothesis is still only tentative—accepted
as the best explanation that we currently have, given the current state
and limits of our knowledge.
Likewise, theories also are tentative. However, theories are so very
well confirmed and supported by many different types of evidence that
they are very, very low on the tentative scale, and are unlikely to
be overturned. A scientific theory is a conceptual framework that
explains a variety of phenomena. Like a hypothesis, a theory is
an explanation. Unlike a hypothesis, theories are exceedingly well supported
by innumerable observations from a breadth of fields of study. Theories
explain facts. They explain a lot of facts. In science, a theory is
as big as you get! Developing explanatory theories is a goal of
science.
This is in stark contrast to the colloquial use of the word theory (and
fact). In general usage, a “theory” is no better than a
guess or a hunch; it is not even a respectable hypothesis. Likewise,
a “fact” is TRUE and is much bigger than a theory. Not so
in science. In science, facts are merely observations (well confirmed
though they may be). Theories, however, have the true powers of explanation
and prediction.
What then, is a scientific “law?” A law is a general
(or universal) statement describing an occurrence or a pattern that
does not vary. It is also tentative (but highly probable). For
example, in chemistry, the law of conservation of energy has been changed
to the law of conservation of matter/energy. It is important to note
that the general misconception is that there is a progression from hypothesis?
theory ? law. This is not the case. Laws, like facts, require explanations,
while hypotheses and theories are explanations. A law can be discovered
and described without an adequate explanation.
The Limits of Science
“For
the scientific method can teach us nothing else beyond how facts are
related to, and conditioned by, each other… Knowledge of what
is does not open the door directly to what should be.”
—Albert Einstein, 1939 in Science and Religion
As
Einstein well understood, science has limits. For example,
some “facts” are not susceptible to scientific investigation.
Private knowledge—emotions, motives and beliefs—cannot be
scientifically tested. I know that I love my child, and that I did not
choose the graduate school I attended based on their basketball team.
But someone else cannot know this about me, unless I tell that person.
Even so, try as I might, I still cannot convince some people that I
did not go to the grad school I chose because of their basketball prowess.
These are completely personal facts, and an objective observer is unable
to independently observe them directly. Science is limited to investigation
of public knowledge—things that anybody can observe. This
is why, for example, individual
revelations3 are not subject to scientific investigation—they
are private matters that are not directly observable by an objective
viewer.
Science is also limited to the study of the natural, physical world.
It is limited to natural explanations of the natural world. Supernatural
explanations are off limits and out of the realm of science. The reason
for this is, simply, methodology. Supernatural explanations are not
testable. A spirit or deity, by its very definition, cannot be held
constant, or controlled, in an experimental design. Therefore, an explanation
involving a supernatural being is not testable, not falsifiable, and
is not scientific. This does not mean that it is wrong; only that it
is not scientific. Science is not anti-religious by its nature; in fact,
it has nothing whatsoever to say about the existence or non-existence
of God or other spiritual beings. These are questions that science simply
cannot address.
Science is limited to understanding the way the world is. Science
is a powerful method for understanding the way the world is. However,
it tells us absolutely nothing about the way the world ought to be or
the way we want it to be. Science cannot tell us what our goals or purposes
in life should be. Science cannot bring meaning to our lives. People
must turn to other ways of knowing, such as religion, meditation, philosophy,
morality, and ethics to understand those kinds of issues. Science is
a way of knowing and understanding our physical world, and it can certainly
inform our decisions. But, what we do with that information is up to
us, as individuals and as a society, to decide. We must also use other
ways of knowing to help us make those decisions.
Teaching
about the Nature of Science
It
has been noted in the literature that one of the values of teaching
evolution is that it provides an opportunity to address the pervasive
misconceptions about science in general, and to teach about the true
nature of science. There are many ways to approach this.
First, know your students. What are their perceptions about
science? This can most easily be done with a survey. If you know your
students and their conceptions, then you can address these explicitly.
See “Surveys on the Nature of Science and
Evolution.”
Next, explicitly address the perceived conflict between science
and religion. Help them to bridge the false dichotomy that is so
pervasive: “if you believe in God, you can’t accept evolution.”
One way to do this is to make students aware of the range of philosophical
beliefs about evolution and religion. See Eugenie
Scott’s Creation/Evolution Continuum.
Scott has also suggested several constructivist exercises, such as brainstorming
what they think is meant by the terms: “evolution” and “creation;”
give them a quiz with quotes about evolution and religion from various
religious leaders, and see if they can figure out who said what. You
could even have them go out and interview their own local religious
leaders. Just being aware of the diversity of opinions can be helpful
in breaking down this false dichotomy of evolution vs. God.
A note of caution: in public schools it is unlawful to promote a specific
religion. Use these methods with great care and sensitivity. The most
important thing is to treat your students’ views with respect,
and make sure students treat each other with respect as well. Students
can feel a very real conflict, which they must resolve or learn to manage
on their own terms, you cannot do it for them.
It is also important to distinguish between science and non-science.
You can talk about how terms are used differently in science and
outside of science (theory, fact, belief, etc.). For example, what
does it mean when a scientist says he believes that bird feathers
evolved for thermoregulation and not flight? Contrast this with what
a Christian means when he says he believes Jesus is the Son
of God. The scientist believes or accepts that bird feathers
evolved first for thermoregulation based on the evidence for this hypothesis
(comparative studies of a large number of birds; reptiles and fossils
suggest that the feathered ancestors of birds could not fly—thus
feathers probably initially served another purpose; thermoregulation
is a plausible alternative explanation for the first function of feathers,
based on other types of evidence). The Christian believes or has
faith that Jesus is the Son of God because of his personal experiences
(maybe this is what his/her parents taught him to believe; maybe he/she
had a personal revelation; maybe it just makes sense to him/her, based
on personal experiences). In the first case, belief was based on objective
public evidence. In latter case, the belief is based on interpretations
of personal experiences. In the future, publicly obtained evidence could
refute the scientific belief. It is not likely, however, to publicly
obtain evidence that would refute the religious belief, since it is
based on personal, private knowledge
.
Discuss what types of questions are appropriate for science,
and what kinds of questions are appropriate for other types of disciplines/ways
of knowing. Is there a God? How should I choose a spouse? What determines
the order of the colors of a rainbow? What is the meaning of life? Is
there a meaning of life? Why do the leaves of maple trees change color
in the fall? Ask a variety of questions like these, and help the students
decide if they are appropriate for a scientific investigation or not.
Help students understand the true nature of science. Give students a
feel for the process of science, not just the end products of science.
Talk about the tentative and self-correcting process of science.
Instead of just presenting the most widely accepted current scientific
view of some topic, give an historical perspective of the scientific
ideas that came before it, and why they were rejected in favor of the
currently accepted idea. For example, give an historical perspective
of the search for the genetic code. How do we know that “DNA holds
the genetic code?” Why do we no longer think that the genetic
code is found in proteins (a once viable hypothesis)?
Use a crime scene investigation as an analogy to investigation
in the historical sciences. How can a police detective “know”
what happened at a crime scene if he/she was not there to witness the
crime? The answer is that events that took place in the past leave clues
that we can use in the present to piece together what happened.
Emphasize the variability in the strength of support that different
ideas have. Craig Nelson’s article: Effective
strategies for teaching evolution and other controversial topics in
The Creation Controversy and the Science Classroom, NSTA has a “Big
Mac” metaphor, with the “meatier” topics being the
ones that are well confirmed (e.g. shared ancestry), with the “bun”
topics being those we do not know as much about (e.g. origin of life).
Lessons and Resources on the Nature of Science
Resources on the Nature of Science
The
website of the Evolution
and the Nature of Science Institutes (ENSI) has many lessons on
the nature of science, in three separate categories: realms and limits,
basic processes, and the social context of science. They also have a
suggested lesson
plan for a unit on the nature of science. Another website to check
out would be Access Excellence’s page: Activities
Exchange Mystery Spot. This site has online mysteries for students
to solve.
PBS’
“Evolution” series has a couple of useful resources.
Check out the last episode of the series, “What About God?”
but not necessarily for use in the classroom. Also check out the video
“Learning and Teaching Evolution,” which is a companion
to the series. This video has four case studies on different aspects
of teaching evolution and the nature of science, as well as seven short
segments from the series that can be used with your students. Segment
one (“Isn’t Evolution Just a Theory?”) is particularly
useful for introducing the nature of science and evolution. Segment
seven (“Why is Evolution Controversial Anyway?”) explores
different viewpoints of the perceived conflict between religion and
science.
Distinguishing
between science and non-science
ENSI
has a lesson, “Of
Sunsets, Souls, and Senses” that explores the limits of science,
and what kinds of topics are appropriate for scientific investigation.
They also have a lesson, “CONPTT:
Science vs Non-Science” that explores the six criteria of
science, to help identify the differences between science and “emerging
science,” “non-science,” and “pseudoscience.”
Another idea is to put together a list of questions and have the students
decide whether the questions are appropriate for a scientific investigation.
Example questions:
What is a sunset?
What chemicals make up the sun?
Is there a God?
Is there such a thing as ghosts?
What makes an object fall to the earth?
Should I get married?
For what purpose am I here?
How can we best treat cancer?
Why do flowers smell good?
Click
here for a printable overhead
Understanding
the true nature of science
ENSI
has several lessons on what they call the “social context”
of science. “Crime
Scene” and the highly recommended “Checks
Lab” both explore the tentative nature of hypotheses.
PBS’
Teacher’s Guide also has several lessons on the nature of
science. Go to the online Teacher’s Guide, click on “download
PDF” under Unit 1: What is the Nature of Science? “Observe
This” and “Different Points of View” are about making
observations and developing hypotheses to explain their observations;
“Solving the Puzzle” is similar to ENSI’s “Checks
Lab.”
Another lesson is to choose a current scientific discovery from the
newspaper. Then find a magazine article on the same discovery, and the
original scientific paper. Every week, the two biggest general science
journals, Science and Nature, as well as other journals give press releases
of “hot” discoveries. Newspapers pick these up pretty quickly,
and then you can find articles in popular periodicals within a month
or so. It is a very interesting lesson to compare science, as written
by scientists in science journals, with the same science written by
journalists for the public (both general and interest-specific). Often,
the social or societal implications of the science are speculated upon
by the journalists, but not by the scientists themselves. This would
be a good opportunity to discuss the limits of science to describing
the way things are; you need to go outside of science to figure out
what to do with this information. This would especially work well if
you have a unit or emphasis on scientific writing.
Another good idea about learning about the nature of science is presented
by Cunningham and Helms (1998; JRST 35: 483-499): learn about the
process of science by actually doing it! They discuss a teacher
who has her students conduct experiments with Fast Plants (Brassica
rapa). Bean seeds also work well. Working in groups, students brainstorm
questions they might ask (based on their observations, etc.), and then
with your guidance, develop hypotheses, figure out how to test those
hypotheses (what treatments to use, including controls), and then conduct
their experiments, collect data, analyze their data, and make conclusions.
Groups of students may come up with their own questions, or the whole
class may be presented with a single question (with which each group
figures out on their own how to address it). The question could be as
simple as: how does fertilizer affect plant growth and development?
Or, how does amount of water available to a plant affect its growth?
This type of lesson will take a month or two to complete, but it is
nice in that students will become aware of what it really is to do science,
with all of the messiness, successes, failures, and decision-making
involved. This is much preferable to an exercise in which they follow
a cookbook formula experiment where there is a “right” answer.
It will also help them to become more aware of how we know something
in science. Instead of just taking for granted that water or nutrients
(for example) are important for plant growth, they will actually discover
this on their own, and in the process, find out how we “know”
something in science.
Resource
List
