Below are a couple of articles about misconceptions in textbooks regarding
Theories vs. Laws.
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William J. Beaty SCIENCE HOBBYIST website
billb@eskimo.com http://amasci.com
EE/programmer/sci-exhibits amateur science, hobby projects, sci fair
Seattle, WA 206-789-0775 unusual phenomena, tesla coils, weird sci
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Re: What is the difference between a theory and a law? http://www.madsci.org/posts/archives/oct99/940942724.Sh.r.html
Date: Mon Oct 25 14:01:29 1999
Posted By: Dan Berger, MadSci Admin
Area of science: Science History ID: 940618768.Sh
Received question:
I recently read a journal article* that spurred my curiosity. The author
stated, "Individuals often hold a simplistic, hierarchical view of the
relationship between theories and laws whereby theories become laws
depending on the availibility of supporting evidence." He added,
"theories and laws are different kinds of knowledge and one can not
develop or be transformed into the other" and, "theories are as
legitimate a product of science as laws."
Throughout my years of undergraduate and graduate education, I have been
taught this "hierarchical view" of theories and laws. As a former
biology professor and current teacher of secondary education, I need to
know, "What is the difference between a theory and a law?" and more
importantly, CAN a theory eventually become a law based on supporting
evidence? I need these questions answered in order to produce
"scientifically literate" citizens, I would surley hate to continue
misleading my students.
*Lederman, N.G. 1998. The state of science education: subject matter
without context. The Electronic Journal of Science. 3(2). http://www.chem.vt.edu/confchem/1998/lederman/lederman.html
(I was unable to locate The Electronic Journal of Science, so I linked
to another presentation of the same material.)
This is a common question, and a common misconception. Unfortunately I
learned it pretty much the same way you did... and didn't really have it
corrected until I started digging into the philosophy of science rather
recently.
The current consensus among philosophers of science seems to be this:
Laws are generalizations about what has happened, from which we can
generalize about what we expect to happen. They pertain to observational
data. The ability of the ancients to predict eclipses had nothing to do
with whether they knew just how they happened; they had a law but not a
theory.
Theories are explanations of observations (or of laws). The fact that we
have a pretty good understanding of how stars explode doesn't necessarily
mean we could predict the next supernova; we have a theory but not a law.
William McComus lists gravity as a modern example of a well-established
law for which no really satisfying theory is available. We can use the Law
of Gravity, and even correct it for the effects of relativity (General
Relativity), but we don't have any consensus notion of how it functions!
Is it geometry or gravitons?
Oddly enough, I searched the MadSci site and came up with a carefully-
written wrong answer along the hierarchical lines you describe above. http://www.madsci.org/posts/archives/dec97/874642409.Ot.r.html
Embarassingly, several answers I summoned in my search fall into the
misconceptions and traps enumerated by McComus!
We shouldn't blame our experts; as you and I have seen from our own
experience, scientists may have fuzzy notions about this sort of
distinction because they don't normally have to make the distinction! A
working scientists doesn't tend to worry about whether the First Law of
Thermodynamics is an explanation, or the Theory of Evolution a statement
of observed facts. They work, she uses them, everything's fine, right? But
as McComus points out, the cut-and-dried (wrong) way this is usually
presented can be pretty deadly, pedagogically.
I am unable to recommend much specific for further reading, although
McComus' bibliography looks to be a good place to start. You might try
Richard Feynman's distinctly practical take on this problem, The Nature of
Physical Law.
Myth 1: Hypotheses
Become Theories Which Become Laws
This myth deals with the general belief that with increased evidence there
is a developmental sequence through which scientific ideas pass on their
way to final acceptance. Many believe that scientific ideas pass through
the hypothesis and theory stages and finally mature as laws. A former U.S.
president showed his misunderstanding of science by saying that he was not
troubled by the idea of evolution because it was "just a theory." The
president's misstatement is the essence of this myth; that an idea is not
worthy of consideration until "lawness" has been bestowed upon it.
The problem created by the false hierarchical nature inherent in this myth
is that theories and laws are very different kinds of knowledge. Of course
there is a relationship between laws and theories, but one simply does not
become the other--no matter how much empirical evidence is amassed. Laws
are generalizations, principles or patterns in nature and theories are the
explanations of those generalizations (Rhodes & Schaible, 1989; Homer &
Rubba, 1979; Campbell, 1953).
For instance, Newton described the relationship of mass and distance to
gravitational attraction between objects with such precision that we can
use the law of gravity to plan spaceflights. During the Apollo 8 mission,
astronaut Bill Anders responded to the question of who was flying the
spacecraft by saying, "I think that Issac Newton is doing most of the
driving fight now." (Chaikin, 1994, p. 127). His response was understood
by all to mean that the capsule was simply following the basic laws of
physics described by Isaac Newton years centuries earlier.
The more thorny, and many would say more interesting, issue with respect
to gravity is the explanation for why the law operates as it does. At this
point, there is no well. accepted theory of gravity. Some physicists
suggest that gravity waves are the correct explanation for the law of
gravity, but with clear confirmation and consensus lacking, most feel that
the theory of gravity still eludes science. Interestingly, Newton
addressed the distinction between law and theory with respect to gravity.
Although he had discovered the law of gravity, he refrained from
speculating publically about its cause. In Principial, Newton states" . .
. I have not been able to discover the cause of those properties of
gravity from phenomena, and I frame no hypothesis . . ." " . . . it is
enough that gravity does really exist, and act according to the laws which
we have explained . . ." (Newton, 1720/1946, p. 547).
(((((((((((((((((( ( ( ( ( (O) ) ) ) ) )))))))))))))))))))
William J. Beaty SCIENCE HOBBYIST website
billb@eskimo.com http://amasci.com
EE/programmer/sci-exhibits amateur science, hobby projects, sci fair
Seattle, WA 206-789-0775 unusual phenomena, tesla coils, weird sci