Ed Poor wrote:
My impression of "pseudoscience", admittedly rather subjective, is that it doesn't ever bother to cite facts. Its hypotheses simply *must* be true. "Junk science", by contrast, does cite facts but does so selectively, deliberately *ignoring* facts which contradict its hypotheses.
I think Ed is using an entirely personal definition of "pseudoscience" that doesn't have much in common with the term as it is generally used. The Wikipedia article on "pseudoscience" does a good job of explaining it, but if you want some further explanation, here's how I discussed the term in my book, "Trust Us, We're Experts":
The very prestige that science enjoys, however, has also given rise to a variety of scientific pretenders--disciplines such as phrenology or eugenics that merely claim to be scientific. The renowned philosopher of science Karl Popper gave a great deal of consideration to this problem and coined the term "pseudoscience" to help separate the wheat from the chaff. The difference between science and pseudoscience, he concluded, is that genuinely scientific theories are "falsifiable"--that is, they are formulated in such a way that if they are wrong, they can be proven false through experiments. By contrast, pseudosciences are formulated so vaguely that they can never be proven or disproven. "The difference between a science and a pseudoscience is that scientific statements can be proved wrong and pseudoscientific statements cannot," says Robert Youngson in his book Scientific Blunders: A Brief History of How Wrong Scientists Can Sometimes Be. "By this criterion you will find that a surprising number of seemingly scientific assertions--perhaps even many in which you devoutly believe--are complete nonsense. Rather surprisingly this is not to assert that all pseudoscientific claims are untrue. Some of them may be true, but you can never know this, so they are not entitled to claim the cast-iron assurance and reliance that you can have, and place, in scientific facts." Judged by this standard, many of the "social sciences"--including the psychoanalytic theories of Freud, Jung, and others--are actually pseudosciences rather than the real thing. This does not mean that Freud and Jung were charlatans or fools. Both were creative thinkers with fascinating insights into the human psyche, but a research methodology that derives its data from the dreams of mentally ill patients is a far cry from the orderly system of measurements that we associate with hard sciences like physics and chemistry.
These points, including Popper's criterion of "falsifiability," are already clear in the Wikipedia article as it currently stands. "Falsifiability" is an excellent conceptual tool. It avoids character assassination and sticks strictly to the question of whether a purported "scientific" claim can be tied to the empiricist methodology that we expect from science.
"Junk science," by contrast, is quite a different beast. Here are a couple of examples of the term in actual use:
Unfortunately, and increasingly today, one can find examples of junk science that compromise the integrity of the field of science and, at the same time, create a scare environment where unnecessary regulations on industry in general, and on the consumer products industry in particular, are rammed through without respect to rhyme, reason, effect or cause.
---Michael A. Miles, former CEO of the Philip Morris tobacco company
Peter Huber of the Manhattan Institute defines "junk science" as "a hodgepodge of biased data, spurious inference and logical legerdemain, patched together by researchers whose enthusiasm for discovery and diagnosis far outstrips their skill" and accuses its practitioners of "data dredging, wishful thinking, truculent dogmatism, and, now and again, outright fraud."
Steven Milloy (who calls himself the "Junkman" and runs the "Junk Science Home Page" at www.junkscience.com) defines junk science as "bad science used by lawsuit-happy trial lawyers, the 'food police,' environmental Chicken Littles, power-drunk regulators, and unethical-to-dishonest scientists to fuel specious lawsuits, wacky social and political agendas, and the quest for personal fame and fortune." He habitually refers to the alleged practitioners of "junk science" using language such as "psychologically challenged," "bogus," "scare mongers," "blowhards," "turkeys," "wacko enviros," etc.
What is striking about all three of these examples is that (unlike the "falsifiability" standard used to define "pseudoscience") they offer no methodological test for distinguishing between "good science" and "bad science." Instead, the authors rely on name-calling and ad hominem attacks on the motives, morals, or competence of people whose conclusions differ from their own. This is fairly typical of people who use the term "junk science," but it isn't typical of people who use the term "pseudoscience."
As for Ed's invitation that I do something with the global warming article -- right now I'm pretty busy with the Disinfopedia and some other projects, but I'll try and take a look at it when I get some time.