A field, practice, or body of knowledge might reasonably be called pseudoscientific when (1) it is presented as consistent with the accepted norms of scientific research; but (2) it demonstrably fails to meet these norms, most importantly, in misuse of scientific method. Subjects may be considered pseudoscientific for various reasons;
Karl Popper considered astrology to be pseudoscientific simply because astrologers keep their claims so vague that they could never be refuted, whereas Paul R. Thagard considers astrology pseudoscientific because its practitioners make little effort to develop the theory, show no concern for attempts to critically evaluate the theory in relation to others, and are selective in considering evidence. More generally, Thagard stated that pseudoscience tends to focus on resemblances rather than cause-effect relations.
Science is also distinguishable from revelation, theology, or spirituality in that it offers insight into the physical world obtained by empirical research and testing. For this reason, both creation science and intelligent design have been labeled as pseudoscience by the mainstream scientific community. The most notable disputes concern the effects of evolution on the development of living organisms, the idea of common descent, the geologic history of the Earth, the formation of the solar system, and the origin of the universe. Systems of belief that derive from divine or inspired knowledge are not considered pseudoscience if they do not claim either to be scientific or to overturn well-established science.
Some statements and commonly held beliefs in popular science may not meet the criteria of science. “Pop” science may blur the divide between science and pseudoscience among the general public, and may also involve science fiction. Indeed, pop science is disseminated to, and can also easily emanate from, persons not accountable to scientific methodology and expert peer review.
If the claims of a given field can be experimentally tested and methodological standards are upheld, it is not “pseudoscience”, however odd, astonishing, or counter-intuitive. If claims made are inconsistent with existing experimental results or established theory, but the methodology is sound, caution should be used; science consists of testing hypotheses which may turn out to be false. In such a case, the work may be better described as ideas that are not yet generally accepted. Protoscience is a term sometimes used to describe a hypothesis that has not yet been adequately tested by the scientific method, but which is otherwise consistent with existing science or which, where inconsistent, offers reasonable account of the inconsistency. It may also describe the transition from a body of practical knowledge into a scientific field.
The following have been proposed to be indicators of poor scientific reasoning.
*Use of vague, exaggerated or untestable claims
*Assertion of scientific claims that are vague rather than precise, and that lack specific measurements.
*Failure to make use of operational definitions (i.e. publicly accessible definitions of the variables, terms, or objects of interest so that persons other than the definer can independently measure or test them). (See also: Reproducibility)
*Failure to make reasonable use of the principle of parsimony, i.e. failing to seek an explanation that requires the fewest possible additional assumptions when multiple viable explanations are possible (see: Occam’s Razor)
*Use of obscurantist language, and misuse of apparently technical jargon in an effort to give claims the superficial trappings of science.
*Lack of boundary conditions: Most well-supported scientific theories possess well-articulated limitations under which the predicted phenomena do and do not apply.
*Lack of effective controls, such as placebo and double-blind, in experimental design.