| Topic: |
Science > Physics |
| User: |
"nospam" |
| Date: |
18 Sep 2006 12:49:41 PM |
| Object: |
Definition of a theory |
What is the difference between:
* a scientific hypothesis
* a scientific theory
* a scientific law
Scientific "law" seems to be a misnomer since, according to the scientific
method, in the unlikely event that someone ever found a credible, testable,
repeatable counter-example, we're obliged to abandon that law. We've even
given up energy conservation for very small \Delta t, and what law is more
sacrosanct than energy conservation?
In that sense, it seems like a scientific law is really no different from a
theory.
And a theory is an hypothesis that has a wealth of verification done in
accordance to the scientific method.
Is this about right?
.
|
|
| User: "Sorcerer" |
|
| Title: Re: Definition of a theory |
18 Sep 2006 02:08:14 PM |
|
|
"nospam" <nospam@nospam.org> wrote in message
news:450edc35@news.henrynet.se...
| What is the difference between:
|
| * a scientific hypothesis -- -a guess
| * a scientific theory -- a stupid guess
| * a scientific law -- see Newton.
|
| Scientific "law" seems to be a misnomer since, according to the scientific
| method, in the unlikely event that someone ever found a credible,
testable,
| repeatable counter-example, we're obliged to abandon that law. We've even
| given up energy conservation for very small \Delta t, and what law is more
| sacrosanct than energy conservation?
|
| In that sense, it seems like a scientific law is really no different from
a
| theory.
|
| And a theory is an hypothesis that has a wealth of verification done in
| accordance to the scientific method.
|
| Is this about right?
No.
Man's laws can be broken; they are not really laws at all, but rules
for governing society. It is "against the law" to drive on the wrong
side of the road, but the wrong side changes from country to
country. Nature's laws CANNOT be broken, it is impossible
to do so. Science is about discovering what those laws are.
Conservation has not be been given up, even if you hypothesize
it has. Your hypothesis is false.
Androcles.
.
|
|
|
|
| User: "" |
|
| Title: Re: Definition of a theory |
18 Sep 2006 02:25:45 PM |
|
|
In article <450edc35@news.henrynet.se>, nospam <nospam@nospam.org> writes:
What is the difference between:
* a scientific hypothesis
* a scientific theory
* a scientific law
Scientific "law" seems to be a misnomer since, according to the scientific
method, in the unlikely event that someone ever found a credible, testable,
repeatable counter-example, we're obliged to abandon that law.
So? Wherever from you got the idea that a "law" is something which is
exact and guaranteed to be eternally correct? A scientific law is a
codification of some relationship between physical observables, and
that's *all* it is. It isn't (and can never be) proven to be exactly
correct and, in fact, there are many laws in use that are *known* to
be only approximately valid, within some limited range of physical
parameters. For example, the gases Law, PV = nRT, is only correct in
the limit of densities going to zero. Ohm's Law, V = IR, is only
approximately correct, and that's for only limited class of materials.
Hooke's Law, F = kx, is only correct in the limit of strains going to
zero. And so on, and so on.
We've even
given up energy conservation for very small \Delta t, and what law is more
sacrosanct than energy conservation?
We have not given up energy conservation, it is just that energy can
only be defined to finite accuracy which is inversely proportional to
the elapsed time. Not the same thing.
In that sense, it seems like a scientific law is really no different from a
theory.
In general, it is far ***less*** than a theory. You propably got
confused by ill informed statements along the lines of "first it is a
theory, but after it is verified it becomes a law". Nope. The
meaning of "theory" in science is a tad different than in common
language. It is not "something conceived but not yet checked", that's
"hypothesis".
A scientific theory, in general is an organized and consistent body of
knowledge which covers a broad range of physical phenomena. Within a
theory there can be various identifiable pieces, which may be brought
in as postulates of the theory or derived within the theory which we
call "laws". Thus, for example, you've the Electromagnetic theory
which covers the whole range of electromagnetic interactions. The
core of this theory are the 4 Maxwell's equations and some of these
equations are known individually as laws, i.e. Gauss' Law, Ampere's
Law, etc. And there are some other pieces of the theory which also
are known as "laws". But, as you can see from this example, a
"theory" is not something a step below a "law" on the ladder, rather
it is a step *above". In general, a scientific theory is a
superstructure that may encompass many individual laws.
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"
.
|
|
|
| User: "RP" |
|
| Title: Re: Definition of a theory |
18 Sep 2006 10:13:28 PM |
|
|
wrote:
In article <450edc35@news.henrynet.se>, nospam <nospam@nospam.org> writes:
What is the difference between:
* a scientific hypothesis
* a scientific theory
* a scientific law
Scientific "law" seems to be a misnomer since, according to the scientific
method, in the unlikely event that someone ever found a credible, testable,
repeatable counter-example, we're obliged to abandon that law.
So? Wherever from you got the idea that a "law" is something which is
exact and guaranteed to be eternally correct? A scientific law is a
codification of some relationship between physical observables, and
that's *all* it is. It isn't (and can never be) proven to be exactly
correct and, in fact, there are many laws in use that are *known* to
be only approximately valid, within some limited range of physical
parameters. For example, the gases Law, PV = nRT, is only correct in
the limit of densities going to zero. Ohm's Law, V = IR, is only
approximately correct, and that's for only limited class of materials.
Hooke's Law, F = kx, is only correct in the limit of strains going to
zero. And so on, and so on.
We've even
given up energy conservation for very small \Delta t, and what law is more
sacrosanct than energy conservation?
We have not given up energy conservation, it is just that energy can
only be defined to finite accuracy which is inversely proportional to
the elapsed time. Not the same thing.
In that sense, it seems like a scientific law is really no different from a
theory.
In general, it is far ***less*** than a theory. You propably got
confused by ill informed statements along the lines of "first it is a
theory, but after it is verified it becomes a law". Nope. The
meaning of "theory" in science is a tad different than in common
language. It is not "something conceived but not yet checked", that's
"hypothesis".
A scientific theory, in general is an organized and consistent body of
knowledge which covers a broad range of physical phenomena. Within a
theory there can be various identifiable pieces, which may be brought
in as postulates of the theory or derived within the theory which we
call "laws". Thus, for example, you've the Electromagnetic theory
which covers the whole range of electromagnetic interactions. The
core of this theory are the 4 Maxwell's equations and some of these
equations are known individually as laws, i.e. Gauss' Law, Ampere's
Law, etc. And there are some other pieces of the theory which also
are known as "laws". But, as you can see from this example, a
"theory" is not something a step below a "law" on the ladder, rather
it is a step *above". In general, a scientific theory is a
superstructure that may encompass many individual laws.
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"
In other words, a theory is statement or set of statements (largely in
mathematical form) describing the specific real sequence of events
underlying some observed macroscopic behavior or behaviors, which
description portends to have explanatory power extending beyond the
range of things already observed, which in turn is the definition of
hypothesis. Laws are in general mathematical/logical truths, and these
become laws of physics only insofar as they are "defined" to be true
relationships between elements in nature, e.g.
E=IR, D=RT, F=dp/dt, etc. From such laws we can derive more complicated
relationships such as
KE1 + PE1 = KE2 + PE2.
Thus the laws of physics are all statements that are defined, either
directly or indirectly, to be true.
Richard Perry
.
|
|
|
|
|
| User: "Sam Wormley" |
|
| Title: Re: Definition of a theory |
18 Sep 2006 12:54:39 PM |
|
|
nospam wrote:
What is the difference between:
* a scientific hypothesis
* a scientific theory
* a scientific law
http://www.dictionary.com/cgi-bin/dict.pl?term=hypothesis
http://www.dictionary.com/cgi-bin/dict.pl?term=theory
http://www.dictionary.com/cgi-bin/dict.pl?term=law
.
|
|
|
| User: "tadchem" |
|
| Title: Re: Definition of a theory |
18 Sep 2006 04:18:07 PM |
|
|
Sam Wormley wrote:
nospam wrote:
What is the difference between:
* a scientific hypothesis
* a scientific theory
* a scientific law
http://www.dictionary.com/cgi-bin/dict.pl?term=hypothesis
http://www.dictionary.com/cgi-bin/dict.pl?term=theory
http://www.dictionary.com/cgi-bin/dict.pl?term=law
To whcih I would like to add my *favorite* site for dictionary
definitions:
http://www.onelook.com/
You may pick from the search results whichever link gives the most
appropriate answer to suit the context of the question.
For example,
http://www.onelook.com/?w=theory&ls=a
yields (among other things)
http://www.lhup.edu/~dsimanek/glossary.htm#theory
"Theory. A well-tested mathematical model of some part of science. In
physics a theory usually takes the form of an equation or a group of
equations, along with explanatory rules for their application. Theories
are said to be successful if (1) they synthesize and unify a
significant range of phenomena; (2) they have predictive power, either
predicting new phenomena, or suggesting a direction for further
research and testing. Compare: hypothesis, and law."
....with active links to the other two terms sought in the OP:
http://www.lhup.edu/~dsimanek/glossary.htm#hypothesis
"Hypothesis. An untested statement about nature; a scientific
conjecture, or educated guess. Formally, a hypothesis is made prior to
doing experiments designed to test it. "
and
http://www.lhup.edu/~dsimanek/glossary.htm#law
"Law. A statement, usually mathematical, which describes some physical
phenomena."
Much of the cr*p that gets posted here is hypothesis. Few will try to
do anything *mathematical* to describe their ideas, i.e. formulate a
law. Fewer still are interested in demonstrating any quantitative
predictive power of their ideas.
Numbers are *so* intimidating, don't ya know?
Tom Davidson
Richmond, VA
.
|
|
|
| User: "Sam Wormley" |
|
| Title: Re: Definition of a theory |
18 Sep 2006 10:59:44 PM |
|
|
tadchem wrote:
Sam Wormley wrote:
nospam wrote:
What is the difference between:
* a scientific hypothesis
* a scientific theory
* a scientific law
http://www.dictionary.com/cgi-bin/dict.pl?term=hypothesis
http://www.dictionary.com/cgi-bin/dict.pl?term=theory
http://www.dictionary.com/cgi-bin/dict.pl?term=law
To whcih I would like to add my *favorite* site for dictionary
definitions:
http://www.onelook.com/
You may pick from the search results whichever link gives the most
appropriate answer to suit the context of the question.
For example,
http://www.onelook.com/?w=theory&ls=a
yields (among other things)
http://www.lhup.edu/~dsimanek/glossary.htm#theory
"Theory. A well-tested mathematical model of some part of science. In
physics a theory usually takes the form of an equation or a group of
equations, along with explanatory rules for their application. Theories
are said to be successful if (1) they synthesize and unify a
significant range of phenomena; (2) they have predictive power, either
predicting new phenomena, or suggesting a direction for further
research and testing. Compare: hypothesis, and law."
...with active links to the other two terms sought in the OP:
http://www.lhup.edu/~dsimanek/glossary.htm#hypothesis
"Hypothesis. An untested statement about nature; a scientific
conjecture, or educated guess. Formally, a hypothesis is made prior to
doing experiments designed to test it. "
and
http://www.lhup.edu/~dsimanek/glossary.htm#law
"Law. A statement, usually mathematical, which describes some physical
phenomena."
Much of the cr*p that gets posted here is hypothesis. Few will try to
do anything *mathematical* to describe their ideas, i.e. formulate a
law. Fewer still are interested in demonstrating any quantitative
predictive power of their ideas.
Numbers are *so* intimidating, don't ya know?
Tom Davidson
Richmond, VA
Thanks Tom.
.
|
|
|
| User: "G=EMC^2 Glazier" |
|
| Title: Re: Definition of a theory |
19 Sep 2006 12:55:08 PM |
|
|
Sam Theories are not carved in stone,and a spacetime will come theories
will be speculation,and the reason for that is accelerates will cost to
much money to give proof to them. In our spacetime the Texas accelerator
could not be built even when it was being built. Even when the Nobel
prize winner Weinberg went before congress fighting for its creation. Go
figure bert
.
|
|
|
| User: "G. L. Bradford" |
|
| Title: Re: Definition of a theory |
20 Sep 2006 02:44:27 AM |
|
|
"G=EMC^2 Glazier" <herbertglazier@webtv.net> wrote in message
news:28584-45102EFC-67@storefull-3338.bay.webtv.net...
Sam Theories are not carved in stone,and a spacetime will come theories
will be speculation,and the reason for that is accelerates will cost to
much money to give proof to them. In our spacetime the Texas accelerator
could not be built even when it was being built. Even when the Nobel
prize winner Weinberg went before congress fighting for its creation. Go
figure bert
If we ever open the space frontier, one will be built. If we don't, it
will never be built. I leave it to you to guess the why of the difference,
if you can.
GLB
.
|
|
|
|
|
|
|
|
| User: "Greg Hansen" |
|
| Title: Re: Definition of a theory |
19 Sep 2006 09:50:53 AM |
|
|
nospam wrote:
What is the difference between:
* a scientific hypothesis
A hypothesis is an assumption made for the sake of argument.
Merriam-Webster has a definition that reflects the scientific sense-- a
tentative assumption made in order to draw out and test its logical or
empirical consequences.
* a scientific theory
A set of assumptions about nature that form the postulates for
deductively making predictions about nature. Phenomena are explained in
terms of the postulates of a theory. Some people want to add the
condition that it be well tested, but I disagree. For instance, the
special theory of relativity was a theory before its first empirical
test-- it was simply an untested theory. It was not an hypothesis,
although it contained several hypotheses-- the principle of relativity,
the invariant speed of light, and implicitly the homogeneity and
isotropy of space.
* a scientific law
A relationship between variables given without an attempt at a deeper
understanding-- a curve fit to sets of data. There is no progression
betwen law and theory-- for instance, Ohm's law was never Ohm's theory,
and the special theory of relativity was never the special law of
relativity.
Scientific "law" seems to be a misnomer since, according to the scientific
method, in the unlikely event that someone ever found a credible, testable,
repeatable counter-example, we're obliged to abandon that law. We've even
given up energy conservation for very small \Delta t, and what law is more
sacrosanct than energy conservation?
Every law and theory has a domain of application, and they are true
within that domain to the extent that they express true relations
between things, e.g. predict the energy of a particle prepared by an
accelerator, the relation being between the preparation and detection.
It shouldn't bother anyone to use a theory like Newtonian gravity that
is known to break down at particularly high speeds or high masses when
you're not using it in the regime where it breaks down.
In that sense, it seems like a scientific law is really no different from a
theory.
In 1885 Johann Balmer discovered a formula that described the spectral
lines emitted by atomic hydrogen,
1/lambda = R(1/4 - 1/n^2)
As a description of the spectra, it is a law. It makes no attempt to
explain it or find a deeper understanding of the phenomena.
And a theory is an hypothesis that has a wealth of verification done in
accordance to the scientific method.
Hypothesis: angular momentum can change only in discrete steps.
That can never become a theory. A theory of what? Bohr applied that in
a theory of the atom, where he also assumed that electrons circle nuclei
as planets orbit the sun, used Newtonian mechanics to analyze the
problem, and made predictions of hydrogen spectra that agreed with
observation (although predictions of the spectra of other atoms were off
the mark). An hypothesis is a single statement assumed true for the
sake of argument, while a theory is a set of hypotheses sufficient to
make physically observable predictions. Although you could, if you
like, call the set of hypotheses a single hypothesis in itself.
Is this about right?
.
|
|
|
|
|
Related Articles |
|
|
