II. Scientists must create operational definitions of the terms
they wish to use so they can communicate effectively with themselves, with
other scientists, and with nonscientists. [2 & 3]
Operational definitions are definitions which present the observations and/or measurements [descriptions] of the people/objects/events who/which are natural phenomena; operational definitions can be used to define complex and abstract concepts, principles and techniques. [ 2, 3 & 4] For example, children often use sentence structures of "_____ [concept/principle being defined] is when _____ [observation/measurement/description of the actions/reactions of people/objects/events being operationally defined]." A child may create an operational definition of love in the following way: "Love is when someone says they like you and they do nice things for you and with you ." The child's observation/measurement/description of the actions/reactions of someone who loves provides an operational definition of the term love .
III. Scientists must follow the scientific method in determining the causality of people/objects/events.
IV. Scientific Proof:
A. Physical Evidence: People/things/events who/which can be seen/heard/touched/smelled/tasted and thus observed and measured directly or indirectly through the use of machines such as telescopes/microscopes/audio amplifiers/etc., or who/which can be inferred by their observed/measured/verified effects upon natural/physical phenomena (people/objects/events comprised of matter/energy and who/which therefore exist in contrast to being the subject matter/content of ideas/dreams/fantasies/etc.)
B. Eyewitness Reports: Testimonies by credible individuals (individuals not known to lie or deceive, and who have no known reasons/motivation to lie or deceive) corroborated by corroborating reports by credible corroborators.
C. Logical Arguments: Arguments in which premises which are verifiable/falsifiable/verified lead logically to conclusions which are true if the premises are true; wherein the premises must answer the begged question: Is this premise true?; wherein verification of the premises must be based upon physical evidence and/or eyewitness reports.
V. Scientists must list the scientific principles they have determined to be scientific principles/laws of nature, so other people can know what the scientists claim to be knowledge. Moreover, scientists must publish/present the observations and measurements of natural phenomena (units of study) by which they created and by which they confirmed/verified their causal hypotheses in order that other scientists may replicate/duplicate their observations and measurements to confirm/deny their causal hypotheses and claims of scientific principles.
When scientists are required to provide detailed descriptions of their
observations and experiments, other scientists can replicate their observations
and experiments and thereby confirm their claims of scientific knowledge.
By this process of constant checking of claims of knowledge, the Code of
Science and the scientific method produce an increasing body of scientific
knowledge. Scientific knowledge created by scientists who follow the Code
of Science and the scientific method may overturn the claims of "experts"
or "authorities" including priests. That has happened throughout the centuries.
People must have the truth--the facts--for making rational decisions, and
the Code of Science including the scientific method offers a way to discover
and learn the truth/facts that is more reliable than the claims of those who
refuse to observe and experiment with the real world people/objects/events
who/which are natural phenomena.
 Charles Proteus Steinmetz.
Four Lectures on Relativity and Space.
Dover Publications, Inc., 180 Varick Street, New York, NY 10014 1967
The fundamental law of physics is the law of inertia. "A body keeps the same state as long as there is no cause to change its state." That is, it remains at rest or continues the same kind of motion—that is, motion with the same velocity in the same direction—until some cause changes it, and such cause we call a 'force.' " [Quotes in the original, but not attributed to anyone.]
This is really not merely a law of physics, but it is the fundamental law of logic. It is the law of cause and effect: "Any effect must have a cause, and without cause there can be no effect." This is axiomatic and is the fundamental conception of all knowledge, because all knowledge consists in finding the cause of some effect or the effect of some cause, and therefore must presuppose that every effect has some cause, and inversely. [Quotes in the original but not attributed to anyone.]
 Stanovich, Keith
How To Think Straight About Psychology
Scott, Foresman and Company, Glenview, IL, 1989
“... In short, the explanation of phenomena, not the analysis of language,
is the goal of the scientist. The key to progress in all the sciences has
been to abandon essentialism and to adopt operationalism ... . [p. 39.]
Where ... does the meaning of concepts in science come from if not from
discussions about language? What are the criteria for the appropriate usage
of a scientific concept? To answer these questions, we must discuss operationism,
an idea that is crucial for the construction of theory in science, and one
that is especially important for evaluating theoretical claims in psychology.”
“Although there are different forms of operationism, it is most useful ... to think of it in the most general way. Operationism is simply the idea the concepts in scientific theories must in some way be grounded in, or linked to, observable events that can be measured. Linking the concept to an observable event is the operational definition of a concept and makes the concept public. The operational definition removes the concept from the feelings and intuitions of a particular individual and allows it to be tested by anyone who can carry out the measurable operations.” [p. 39.]
“The link between concepts and observable operations can vary greatly in [the] degree of directness or indirectness. Some scientific concepts are defined almost entirely by observable operations in the real world. [Other] concepts [are] defined only partially by these direct links. ...[The] use of some concepts is determined by both a set of operations and the particular concept’s relationship to other theoretical constructs. [There] are concepts that are not directly defined by observable operations but are linked to other concepts that are. These have only an indirect operational definition, one that comes from other concepts that are defined more directly by observable operations.” [p. 40.]
“Thus, although theoretical concepts differ in how closely they are linked to observations, all concepts acquire their meaning partially through their link to such observations, a point emphasized by noted Harvard philosopher W. V. Quine: ‘The sentences of science, no matter how theoretical, acquire what meaning they have through a network of sentence-to-sentence links whose starting point is sensory stimulation. All evidence for the truth of a scientific theory, moreover, is drawn from sensory observation through the same network.’ (1985, p. 32.) In short, operationism, not debate about language, determines the meaning of concepts in science.” [p. 40.]
“[Operationism] is not unique to psychology. It is characteristic of all sciences. ... This is what makes possible the public nature of science, one of its defining features. Two different scientists agree on the same operational definition so that is possible for one to replicate the other’s results.” [p. 43.]
 Greene, Brian
The Elegant Universe
Vintage Books, Random House, Inc. New York, 2000
The most meaningful definitions in physics are those that are operational—that is, definitions that provide a means, at least in principle, for measuring whatever is being defined. After all, no matter how abstract a concept is, having an operational definition allows us to boil down its meaning to an experimental procedure for measuring its value.
 Greene, Brian
The Elegant Universe
Vintage Books, Random House, Inc. New York, 2000
"The physicist Ernest Rutherford once said, in essence, that if you can't explain a result in simple, nontechnical terms, then you really don't understand it. He wasn't saying that this means your result is wrong; rather, he was saying that it means you do not fully understand its origin, meaning, or implications."