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Re: What are "principles" in science?



Chuck Britton wrote:

I'm using Theory here to
represent the 'accepted' explanation rather than the 'proposed but
not yet accepted' explanation that some would prefer.

Who are "some" - the general populace (as opposed to the scientific
community)?

I think the scientific community uses theory to indicate "accepted
explanation" and hypothesis to mean "proposed but not yet accepted
explanation or pattern".

Theory of
Evolution and Theory of Relativity are relevant here. These
could/should be called 'Laws' since they are generally accepted as
true and not derivable from more basic truths.

While the general populace might agree with you, I don't think
the scientific community would. Calling them laws just because
they are accepted would go against the traditional use of
the term - in the most general terms (I know there is no
hard and fast rule), theories are explanations and
laws are patterns. For example, Ohm's law is a law
because it is based on an empirical pattern, not an
explanation. Theories don't become laws nor visa-versa.

Principles, on the other hand, are more like "assumptions",
as you say (I like to call them "guiding principles").
Conservation of mass, for example, is a principle.

I have come to refer to Kirchoff's Rules instead of Laws, reserving
the use of Law to stand for a basic 'truth' that cannot be derived
from a MORE basic truth. i.e. Conservation of Energy and of Charge
can be used to 'derive' the Loop and Junction 'rules'.

I likewise refer to Kirchoff's rules, not laws. However,
it is not because they can be derived from more basic
ideas but rather because I use them *after* I derive them from
more basic ideas. Originally, they may have been simply
an empirical observation (and thus properly called laws)
but my students encounter them after an examination of
conservation of charge and energy and so, in their mind,
they are more properly called rules.

____________________________________________________
Robert Cohen; 570-422-3428; www.esu.edu/~bbq
East Stroudsburg University; E. Stroudsburg, PA 18301


-----Original Message-----
From: Chuck Britton [mailto:britton@ncssm.edu]
Sent: Monday, June 07, 2004 10:45 AM
To: Robert Cohen; Forum for Physics Educators
Subject: Re: What are "principles" in science?

Heisenberg's Uncertainty Principle and the Principle of Least Action
are the two physics uses of the term that come to my mind. These are
specific and basic 'assumptions' or postulates in my book.

I have come to refer to Kirchoff's Rules instead of Laws, reserving
the use of Law to stand for a basic 'truth' that cannot be derived
from a MORE basic truth. i.e. Conservation of Energy and of Charge
can be used to 'derive' the Loop and Junction 'rules'. 'Rules' are
handy results of more basic theory. I'm using Theory here to
represent the 'accepted' explanation rather than the 'proposed but
not yet accepted' explanation that some would prefer. Theory of
Evolution and Theory of Relativity are relevant here. These
could/should be called 'Laws' since they are generally accepted as
true and not derivable from more basic truths.

We scientists aren't very consistent with our use of these
mathematical/philosophical terms nor should we demand rigid
consistency. But just a TAD of consistency would improve our impact
on those others who face scientific terms as outsiders.