“There are four primary logical criteria for a theory. It must be (1.a) a simple unifying idea that postulates nothing unnecessary (‘Ocam’s Razor’); (1.b) Logically consistent internally; (1.c) logically falsifiable (i. e., cases must exist in which the theory could be imagined to be invalid); (1.d) clearly limited by explicitly stated boundary conditions so that it is clear whether or not any particular data are or are not relevant to the verification or falsification of the theory.”

“Four empirical criteria are of primary importance as well. A theory must (2.a) be empirically testable itself or lead to predictions or retrodictions that are testable; (2.b) actually make verified predictions and/or retrodictions; (2.c) concern reproducible results; (2.d)provide criteria for the interpretation of data as facts, artifacts, anomalies,or as irrelevant.”

“Sociological criteria also exist for determining the validity of a theory. A theory must (3.a) resolve recognized problems, paradoxes, and/or anomalies, irresolvable on the basis of preexisting scientific theories; (3.b) pose a new set of scientific problems upon which scientists may work; (3.c) posit a ‘paradigm’ or problem-solving model by which these new problems may be expected to be resolved; (3.d) provide definitions of concepts or operations beneficial to the problem-solving abilities of other scientists.”

“Finally, there is a fourth set of theory criteria as well: historical ones. A theory must (4.a) meet or surpass all of the criteria set by its predecessors or demonstrate that any abandoned criteria are artifactual; (4.b) be able to accrue the epistemological status acquired by previous theories through their history of testing—or, put another way, be able to explain all of the data gathered under previous relevant theories in terms either of fact or artifact (no anomalies allowed); (4.c) be consistent with all preexisting ancillary theories that already have established scientific validity.”