The famous theory of Albert Einstein is usually called his *Theory of Relativity,* but he thought it should be called a *Theory
of Invariance,* and I agree. Why?

As explained in my Detailed
Overview of Scientific Method: "Another strategy [for inventing theories] is to construct
a
theory, using the logic of internal consistency, by building on the foundation
of a few
assumed
axiomatic components. In mathematics, an obvious example is Euclid's geometry. An
example from science is Einstein's theory of Special Relativity; after
postulating that** two things are constant** — the
observed
speed
of
light, and physical laws in uniformly
moving
reference frames *** **—
logical
consistency, which
Einstein
explored with mental experiments and mathematics, makes it necessary that
some properties (length, time, velocity, mass,...) will be relative while other
properties
(proper length, proper
time,
rest mass,...) are constant. [***** it's *uniformly
moving
reference frames* for Special Relativity,
but
for
General Relativity it's *all reference frames*]"

Here is a summary of his *foundational
assumptions *(of
Invariant Constancy for some things)

and the *logically derived consequences* (of Relativity for other things):

1. Invariances (constancy) |
→ |
2. Relativities |

Assume these are constant: |
→ |
which makes these relative: |

the observed laws of physics, | observed | |

the observed speed of light. | length, time, velocity, mass, ... |

Chapter
16 of my book, *Power
Tools for Problem Solving in Physics, *explains*
* • the

• the

For a non-mathematical introduction to the essential ideas of invariance-and-relativity, read the first two pages (Section 16.1 and part of 16.2) and stop when I ask, "Are you convinced?" Then continue reading if you want to master the basic math, which isn't difficult.

In his original 1905 paper about invariance, "On the Electrodynamics of Moving Bodies" (here translated from German into English), Albert Einstein did call his first postulate *the Principle of Relativity.* But later he regretted this name, because the logical foundation of his theory is constancy, and because he saw the silly analogies that people drew between his theory about *relativity in physics* and their ideas about *relativity in ideology, *to claim support for their ideas about relativism and subjectivism.* * People extended his claims about the relativity of specific things (time, space, and mass) into claims about the relativitity of everything (including values and ethical standards) in all areas of life, as if Einstein was saying "everything is relative." But he never said this.

Here are some quotations about invariance and relativity:

Relativity applies to physics, not ethics. { **Albert Einstein** }

Albert Einstein was unhappy about the name "theory
of relativity". He preferred "theory of invariance". The
reason is that [one] cornerstone of his 1905 theory of relativity is that
the measured velocity of light is the same (invariant) regardless of any
relative
motion between a laboratory and the source of light. What Einstein
feared came to pass when the popular catchphrase of his theory became "everything
is relative." It was snatched up by people not acquainted with
the scientific context, who regarded the theory as evidence in support of
their own social views. { **Arthur Miller**, from a letter
in New
Scientist }

In actual fact, the theory of relativity is anchored
in absolutism — in the
concrete of Einstein's two postulates: The velocity of light is a universal
constant, and
the laws of physics are constant. He described these postulates as principles
of invariance. An insightful textual analysis of the introductory sections
of
the 1905 paper would have recognized that the two "postulates" specify
unchanging principles that serve as the foundations of the theory. In
fact, Einstein
called his creation an "Invariententheorie," a theory of invariance. The
name "theory of relativity" was coined later in a review by German
physicist Max Planck. Einstein resisted that name for years, although
he reluctantly bowed to peer pressure. The relativistic features of time
and space
that led
to the term "theory of relativity" are derived from the principles
of invariance. { quoted from POSTMODERNIST
RHETORIC DOES NOT CHANGE
FUNDAMENTAL
SCIENTIFIC FACTS by
**Irving M. Klotz**, who is a Morrison Professor, Emeritus, in the departments
of chemistry and of biochemistry, molecular biology, and cell biology at Northwestern
University }

and Relativity
& Quantum
Physics from the **International
Catholic University**:

The fundamental principle underlying
the theory of relativity it that the laws of nature always have the same
form for all observers. This
follows
from
our belief that there are laws that describe, precisely and mathematically,
the connections between causes and effects. This invariance of the laws
of nature sometimes called the principle of covariance, or the principle of
relativity. It says that the laws of nature are completely objective,
and do not depend on who is looking at the phenomena or from what vantage point.

Einstein began by asking himself a very simple question: What
would a light wave look like to someone who is travelling alongside it? It
was known that
a light wave is an electromagnetic wave that is described by Maxwell's equations,
so he looked for a solution of these equations that describe a stationary light
wave, and found that there is none. However we describe a light wave,
it is always moving with the speed of light.

This led him to study very carefully the transformation
equations that relate the spatio-temporal co-ordinates of events in one frame
of reference to those
in another frame moving with constant velocity with respect to the first. It
had always been assumed to be obvious that these transformation equations are
those due originally to Galileo. Furthermore, it was also considered
obvious, according to the principle of relativity, that our description of
phenomena
should give the same result whichever reference frame we use. Einstein
realised that Maxwell's equations do not satisfy this condition; they
are not invariant under the Galilean transformation.

So he asked himself what the transformation would have to
be to ensure that the light wave looks the same to all observers, whatever their
relative velocities. This was already known to be the Lorentz transformation. He
then asked what would be the consequences of assuming that the Lorentz transformation
applied
to all phenomena, not just to light waves, and found that this enabled him
to explain many apparently anomalous results, such as that of the Michelson-Morley
experiment. ...<snip>...

The popularity of the theory of relativity among the general
public, reinforced by the image of Einstein as the typical scientist, gave impetus
to the idea
that physics is relative, and thence that everything is relative. If
Einstein had called his work the theory of invariance, we would perhaps have
been spared this nonsense.

This website for Whole-Person Education has TWO KINDS OF LINKS:
an ITALICIZED LINK keeps you inside a page, moving you to
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Here are other related pages:

Reality 101 & Postmodern Relativism — Truth and Theory |

This page, written by Craig Rusbult, is

http://www.asa3.org/ASA/education/**views/invariance.htm **

Copyright © 2007 by Craig Rusbult, all rights reserved