The Virtues of Scientific Theory
Defining a Theory in a Scientific Sense
A scientific theory begins as a hypothesis. This is a proposed explanation for physical phenomena either observed naturally or the result of scientific experimentation. In order for a hypothesis to be a scientific hypothesis it must have testable elements. Within the confines of the scientific method this involves predictions drawn from hypothesis that are tested through experimental design. These experiments either provide validation or a lack of validation regarding the prediction and in turn bolsters or weakens the hypothesis.
Once a scientific hypothesis has been confirmed and reconfirmed unfailingly through experimentation and observation it becomes a Theory. The scientific method, including experimental design, double blind studies, peer review, and replicability of experimental results, is used to garner inductive evidence for the theory. Inductive evidentialism is the use of specific facts in the formulation of a theory that can collectively explain and unify said observable facts.
The hallmark of a strong scientific theory is it's ability to make falsifiable predictions. For instance, the theory of evolution predicts that we will never find a rabbit skeleton in the pre-Cambrian geological strata. If we ever did find such a fossil the theory would be all but disproven (or at least in need of serious revision.)
The Attributes of a Good Theory
There are five basic criterion which a good Theory should meet;
1. It should be falsifiable and make predictions. To stay with the example of evolution, the predictions of evolution are the basis for all modern inoculation and anti-biotic development. And the assumptions upon which the Theory operates always work in the production of new more efficacious medical treatments.
2. It should be buttressed by independent evidence. For instance observations and experimentation in Comparative Anatomy, Anthropology, Molecular Chemistry, Paleontology, Plate Tectonics, Dendrology, Embryology, Micro-Biology, Radiometric Dating, and Pharmacology all converge on the Theory of Evolution.
3. It must be consistent with pre-existing theories. New evidence may cause us to re-examine and hone existing theories, it may cause us to discard out-dated theories, or it may help us to consolidate theories such as was the case with electricity and magnetism which were unified by Faraday into the convergent theory of Electromagnetism.
4. It can be adapted and honed to accommodate new information. To return to the example of Evolution, it was once thought that mutation could supply the sufficient genetic variation for speciation, now that is in question and the field of epigenetics is helping us to better understand the mechanisms of genetic drift. This does nothing to undermine the central tenet of common origin amongst all forms of life but rather helps us hone our understanding of speciation.
5. It should dispense with unneeded assumptions and superfluous hypothesis. This economy of thought is called parsimony. An example of this would be when Laplace presented his orrery, or working model of the solar system, to Napoleon. Napoleon mentioned that there doesn't seem to be any place for god in your design and Laplace replied that he had no need of that hypothesis. The mathematics worked without such an extraneous assumption.
Theories versus Laws
Scientific Laws are accounts of how the physical world behaves given certain circumstances. Newton's Laws of motion are a good example. Inertia, the Force equation, and equal and opposite reactions are simply observable every time they are looked for or tested for.
A Theory on the other hand is more encompassing. Newton's laws laid the ground work for the Unified Theory of Relativity and for much of Quantum Field Theory. Both these theories make use of these laws in the inductive formation of more expansive scientific endeavors that explain and integrate the macro and the micro behavior of matter.
Theories and Laws are different epistemological categories, a law does not ever become a theory nor does a theory ever become a law but rather laws are used to formulate theories and theories unify interrelated laws. They can both, unlike a hypothesis, be consider scientific fact.
Not Your Everyday Theories
And so what I hoped to demonstrate is that to disparage a scientific theory as, "just a theory," is to profoundly misapprehend the difference between the scientific use of the word and the colloquial uses of the word. (i.e. Theory of how a crime was committed.)
Examples of Scientific Theories which are all on the same level of verifiability are;
The Atomic Theory, The Germ Theory, The Theory of Evolution, The Heliocentric Theory, The Theory of Gravity.
To deny any scientific theory is to either betray a profound lack of scientific literacy or a complete indifference to physically observable phenomena and evidence of an empirical nature.