SCIENTIFIC THEORY
IF SCIENCE is
 The observation, identification, description, experimental investigation, and theoretical
explanation of phenomena.
 Methodological activity, discipline, or study
 An activity that appears to require study and method
then, science can be characterized as a method of obtaining reliable — though not infallible —
knowledge about the universe around us. This knowledge includes both descriptions of what
happens and explanations of why it happens.
The knowledge is reliable because it is continually tested and retested — much of science
is heavily interdependent, which means that any test of any scientific idea entails testing other,
related ideas at the same time. The knowledge is not infallible, because at no point do scientists
assume that they have arrived at a final, definitive truth.
The knowledge involved is that about the universe around us, and that includes us as
well. This is why science is naturalistic: it is all about natural processes and natural events.
Science involves both description, which tells us what has happened, and explanation, which
tells us why it happened. This latter point is an important factor because it is only through
knowing why events occur that we can predict what may occur.
Science can also at times be characterized as a category or body of knowledge. When this
is how the term is used, the speaker usually has in mind just the physical sciences (astronomy,
geology) or biological sciences (zoology, botany). Finally, science is often used to refer to the
community of scientists and researchers who do scientific work. It is this group of people who,
through practicing science, effectively define what science is and how science is done.
Philosophers of science attempt to describe what an ideal pursuit of science would look like, but
it is the scientists who establish what it will really be.
The Philosophy of Science is concerned with how science operates, what the goals of
science should be, what relationship science should have with the rest of society, the differences
between science and other activities, etc. Everything that happens in science has some
relationship with the Philosophy of Science and is predicated upon some philosophical position,
even though that may be rarely evident. Moreover, the philosophy of science is that arena in
which theory is developed and tested.
To be considered a scientific theory by most scientists and philosophers of science, a
theory must meet most, if not all, of certain logical, empirical, sociological and historical criteria.
These groupings are important because most people tend to focus only on the logical and
empirical criteria - it is easy to forget that science also encompasses important social and
historical aspects which play a role in how theories are evaluated.
Logical Criteria
A scientific theory must be:
 a simple unifying idea that postulates nothing unnecessary ("Occam's Razor")
 logically consistent
 logically falsifiable (i.e., cases must exist in which the theory can be imagined to be
invalid)
 clearly limited by explicit boundary conditions so that it is clear whether or not particular
data are or are not relevant to verification or falsification
The above logical criteria are among the most cited when it comes to discussions about the
nature of scientific theories and how science differs from nonscience or pseudoscience. When a
theory includes unnecessary ideas or is inconsistent, it becomes difficult to see how it actually
explains anything. When a theory is not falsifiable, it is impossible to tell if it is true or not, and
thus it won't be possible to correct it via experimentation. Finally, when there aren't any clear
boundaries, we'll never know if particular observations count for or against it.
Empirical Criteria
A scientific theory must:
1. be empirically testable or lead to predictions or retrodictions that are testable
2. actually make verified predictions and/or retrodictions
3. involve reproducible results
4. provide criteria for the interpretation of data as factual, artifactual, anomalous or
irrelevant
The above criteria are not cited quite as often as the logical criteria, but they come close. A
theory which cannot be tested empirically is useless for researchers. A theory which has not
made any actually verified predictions might prove useful in the future when its predictions are
verified, but not currently.
A theory which cannot provide retrodictions (to utilize present information or ideas to
infer or explain a past event or state of affairs - e.g., to "retrodict past eclipses" as opposed to
predicting future eclipses) may also be useful in the future, but not currently. If a theory's results
cannot be reproduced, it is impossible to determine if those results were ever actually valid
(rather than the result of error or fraud).
Finally, a scientific theory must allow us to better understand the nature of the data we
have - after all, not all data are valid for a particular theory. Some data may be interpreted as
factual (that is, they fall within the boundary conditions specified by the theory and verify its
predictions or retrodictions); some may be artifactual (that is, the result of secondary or
accidental influences lying outside the boundaries set for the validity of the theory); some are
anomalous (that is, demonstrably valid within the bounds of the theory, but also at odds with
predictions or retrodictions made by the theory); some are irreproducable and thus invalid; and
some are irrelevant since they address the theory not at all.
Sociological Criteria
A scientific theory must:
1. resolve recognized problems, paradoxes, and/or anomalies irresolvable on the basis of
preexisting theories
2. pose a new set of scientific problems upon which scientists may work
3. suggest a "paradigm" or problem solving model to help resolve these new problems
4. provide definitions of concepts or operations which will help other scientists solve
problems.
The above criteria are more often recognized by critics than supporters of science. This is
unfortunate because they are not actually problems - on the contrary, they underscore the fact
that science is generally something ultimately done by a community of researchers and that many
scientific problems are problems discovered by the work of a community.
Thus, a scientific theory must address some problem which the scientific community
needs resolved. It need not be an old problem; in fact the articulation of the theory can itself be
the means of informing people about the problem. However, if there is no actual problem and we
are not looking at an issue which is already covered by other theories, then how can this new
theory qualify as scientific? Furthermore, this new theory must offer a means of resolving the
problem - simply pointing it out isn't enough.
Historical Criteria
A scientific theory must:
1. meet or surpass all of the criteria set by its predecessors or demonstrate that any
abandoned criteria are artifactual
2. be able to explain all of the data gathered under previous relevant theories in terms
either of fact or artifact (no anomalies allowed)
3. be consistent with all preexisting ancillary theories that already have established
scientific validity
These historical criteria are closely related to the sociological ones. A scientific theory does not
need to simply solve some problem, but it needs to do so in a way which is superior to other,
competing theories which people have offered in the past. In addition, a good theory needs to be
able to explain more data than the competition - scientists prefer fewer theories which explain
more things rather than many theories, each of which explains very little. All of this is what
ensures that scientific theories increase in their explanatory power.
Legal Criteria
Although many would not actually list any legal criteria for scientific theories (and
ideally, there wouldn't be), as science is a matter of research, not a matter of law. However, in
1981, there was a trial in Arkansas over an "equal treatment" law that made creationism a
required subject which had to be taught whenever evolution was taught. This law was challenged
and overturned, as were similar laws elsewhere. Ultimately the U.S. Supreme Court made the
determination that such laws were unconstitutional.
The Arkansas trial is frequently highlighted because it was the first of its kind, and also
because of the very comprehensive judgment that came out of it. The trial had several high
profile, well known scientists involved in giving evidence, including descriptions of science, so
the outcome of the trial has some relevance. In his ruling, Judge Overton found that science has
four essential features:
1. It is guided by natural laws, and is explanatory by references to natural laws.
2. Science is testable against the empirical world.
3. Its conclusions are tentative, not the final word.
4. It is falsifiable.
These criteria are compatible with or repeat the more detailed criteria outlined above. So, at least
in the U.S., there is a legal precedent for answering the question, "what is science?"
Summary
Overall, the criteria for scientific theories can be loosely be summarized by a few basic
principles. Scientific theories are:
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Consistent (internally and externally)
Parsimonious (sparing in proposed entities or explanations)
Useful (describes and explains observed phenomena)
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Empirically Testable & Falsifiable
Based upon Controlled, Repeated Experiments
Correctable & Dynamic (changes are made as new data is discovered)
Progressive (achieves all that previous theories have and more)
Tentative (admits that it might not be correct rather than asserting certainty)
It is true that the exact nature of science is open for debate, and some if not all of these criteria
could be questioned. However, in practice, the above criteria are a pretty good description of
characteristics that one would expect a theory to posses for it to be considered a scientific theory.
Lacking one or two might not mean that a theory isn't scientific, but only if there are very, very
good reasons; lacking most or all, however, will certainly disqualify an idea from being
genuinely scientific.