Skeptics differ over how widely skepticism as a movement should cast its net. Here I would like to discuss where to place the boundary between science and pseudoscience.
Hypotheses range from those which are almost certainly true to those which are surely false. How skeptics should react to false hypotheses depends on how widespread and influential they are. A belief which is demonstrably false but which is held by only a few people, particularly people who are not in a position to influence our lives, may not be worth bothering about.
While perhaps worthy of a historical or a psychological study, belief in a flat earth is not, currently, a major threat to civilization or worth much skeptical attention. Although I sometimes use the Flat Earth Theory as an example of an apparently self-evident belief which turns out on research to be false, I would hardly expect to see a skeptical publication arguing the case for a spherical earth. Even James Randi, in Flim-Flam, apologized for presenting the case against the Cottingley Fairies. However, his chapter on the subject showed investigation in action and cast an interesting light on the personality of Sir Arthur Conan Doyle.
To be worth tackling, a false belief should be either widespread, be influential or have a direct impact on people's financial, physical or emotional well-being. Belief in government UFO cover-ups, astrology, perpetual motion and chiropractic come into this category, to pick a few at random. These are areas in which a little skeptical attention pays dividends in human happiness.
To digress, I see skepticism as a form of altruism, as my thing I do for humanity. It would be nice to make the world fitter for critical thinkers to live in, but this is a selfish aim. Our actions and our advice can also improve other people's lives.
Someone who has been influenced by a skeptic is less likely to be scammed out of their life's savings or is more likely to seek valid medical attention.
They should be better able to plan a happy and productive life, and to achieve meaningful aims, than is someone who believes in fate, luck or their stars. They should certainly be less likely to commit suicide to board a UFO behind a comet. Skeptics should aim, not just for acceptance, but for welcome. I dream of the day when people needing advice will call a skeptic, not a psychic.
Returning to hypotheses, there are, at the other end of the scale, beliefs which are the subject of genuine scientific controversy. At present the evidence may be equivocal but, we can assume, the matter will eventually be settled, one way or the other. Skeptics should take an intelligent interest but need not get directly involved.
Is the universe open or closed? Some cosmologists have an almost religious need for the universe to be trembling on the brink between eternal expansion and eventual collapse. They spend their time looking for "missing mass" to make this belief come true. The average skeptic is unlikely to have either the knowledge or the motivation to take sides. As skeptics do so often, we must sit on the fence until the evidence is in.
In the sciences though, once strong evidence is in, it becomes perverse to support a contrary view. The majority opinion may be wrong, in the past it sometimes has been, but this is self-correcting. (Continental drift is the classical case in point.)
Science is a very competitive field. If there is the slightest chance of proving someone wrong, there is instant fame, if not fortune, awaiting the person who does it. Science is the one arena in which ideas are ruthlessly tested -- provided one can get the funding.
This doesn't stop individual scientists from pursuing pet theories far beyond reasonable bounds. Respected astronomers Sir Fred Hoyle and Chip Arp have, both in their own way, attacked cosmological expansion as the explanation for the Red Shift.
They can't both be right. Physicist Thomas Gold supports Hoyle, but he also believes that oil comes from reservoirs of deeply buried primordial methane. He hasn't found any. Retro-virus expert Peter Duesberg insists that HIV doesn't cause AIDs. Nobel Prize-winning chemist Linus Pauling was sure that vitamin C could cure cancer and even Einstein could never be convinced that quantum theory was true.
These are examples of qualified scientists who have gone beyond, or who have ignored, the evidence. Odd-ball though their ideas may be, these ideas are not pseudoscience, they are part of legitimate scientific controversy. Their validity is being addressed by the community of scientists; well-meaning amateurs can probably do little to help.
Unfortunately, reporters like controversy and many people have a vested interest in "proving scientists wrong" so it's the goofy theories which get the most attention in the non-scientific press. Scientists publish in scientific journals, but beyond a certain point the journals, or their referees, say, "enough is enough" and they stop publishing the pottier theories. The non-scientific press then becomes the proponents only outlet. This makes for interesting articles but it gives people a skewed impression of current scientific opinion.
The Scientific American is a usually reliable source, although even it will occasionally print an article on a minority viewpoint without comment. It makes up for this by having a vicious letters column. (e.g. "I respond to Mr M______ at the risk of giving greater credibility to his remarks than they deserve. I wish merely to enumerate his many errors of fact and logic.")
Scientific articles in the more popular journals should be taken with a big pinch of salt. The quality of newspaper articles depends greatly on the knowledge and dedication of the individual reporter; the Philadelphia Inquirer's Faye Flam, for example, has been doing an excellent job on scientific topics. As for the tabloids, they wouldn't know a scientific fact if it fell on top of them. Just for once I'd like to see a tabloid headline, "The Truth about Roswell -- top scientist proves people who believe in crashed saucers are fruitcakes."
Where the facts are clear, we should promulgate them. However, science, by its very nature, is tentative. There are many areas where skeptics may have opinions but where advocacy would be unproductive. While controversy continues we can do little but wait, and vote for research funding. Once the controversy is over it would be pointless to support the losing side.
Meanwhile, between the trivial and the contentious, there is still a huge field of pseudoscience for skeptics to tackle. This is where we can do the most good and this is where we should be concentrating our efforts.
"What is rarely understood by the lay public is how ready, how eager, how desperately the collective science community in a given discipline welcomes the intellectual iconoclast -- if he or she has the goods."