The reason people believe odd, extravagant, and just plain wrong ideas is because people lack the necessary tools to separate fact from fiction. The main weapon in any skeptic's arsenal is the Baloney Detection Kit or BDK. According to Carl Sagan's book, The Demon-Haunted World, there are two sets of tools in the BDK. The first set describes logical thinking that must be carried out. One must find independent confirmation of facts, encourage debate from both sides of the argument, and spin multiple hypotheses, though one must not get overly attached to a hypothesis. Remember, we are trying to figure out the truth, not what we want to be the truth. Also, one must be able to quatify whenever possible. Data can be studied and the truth will emerge from the results. If there is a chain of argument, every link in the chain must work. Stay true to Occam's Razor. When in doubt, the simplest possible answer is usually the best. And finally, ask whether the hypothesis is at least in theory falsifiable. Untestable hypotheses by definition are not science and subsequently have no credibility.
From here, Sagan moves on to the common errors in thinking that promoters and consumers of pseudoscience often committ. The first is ad homonem, or "to the man". This occurs when the arguer is attacked, not the counter argument. A common example would be not giving a man's argument on evolution any attention because he is a priest. Another very common error in thinking is the argument from authority. Just because the person is a figure of authority does not mean they are immune from error themselves. Next is the argument from adverse consequences. In this error in logic, the arguer believes he must be right because the other outcome would be disastrous, such as the defendant in a publicized murder trial must be found guilty, otherwise it will encourage other men to murder their wives. Appeal to ignorance proposes that is a claim is not disproven, then it must be true and vise versa. Also known as absence of evidence is not evedence of absence. Bigfoot and Loch Ness enthusiasts pull this card all the time. Special pleading is usually pulled to rescue a proposition in deep rhetorical trouble, such as "How can there be an equally godlike Father, Son, and Holy Ghost in the same Person?" special plead; "You don't understand the Divine Mystery of the Trinity". Next up is beggin the question, or assuming the answer. "We must institute the death penalty to discourage violent crime". This is actually a step worse than assuming correlation. In this logical fallacy, no data is even interpreted. The next logical error is a common psychological phenomena. People tend to remember only the evidence that is in their favor, not in opposition to them. People also have trouble understanding the statistics of small numbers. "They say 1 out of every 5 people is Chinese. How is this possible? I know hundreds of people, and none of them is Chinese". People actually have trouble understanding statistics in general. President Eisenhower expressed astonishment and alarm upon discovering that fully half of all Americans have below average intelligence! Another error in logical thinking concerns inconsistency, such as attributing the declining life expectancy in the former Soviet Union to the failures of Communism, but not attributing the high infant mortality rate in the US to the failures of capitalism. Next up is non sequitur or it does not follow. A popular one is "Our nation will prevail because God is great", when in reality every nation says such things. Post hoc, ergo propter hoc or it happened after, so it was caused by, is another very common error associated with confusion of correlation and causation. Professor Berg's post about vitamin c supplements is a perfect example. Sagan continues on with the meaningless question, such as what happens when an irresistable force meets an immovable object? This is not a falsifiable situation and thus lies outside the scope o science. The excluded middle or false dichotomy occurs when people only consider the two extremes on a continuum, such as either you love your country or you hate it. Short term vs. long term is related to the excluded middle, but Sagan makes a special mention to this. One example is why explore space or pursue fundamental science when we have so huge a budget deficit? The slippery slope is related to excluded middle where one decision will lead to extreme consequences, such as if we allow abortionin the first weeks of pregnancy, it will be impossible to prevent the killing of a full-term infant. Confusion of correlation and causation we have discussed in class with the example of crime and ice cream sales. Suppressed evidence or half-truths are similar to counting the hits and forgetting the misses, where only the "facts" in the argument's favor are recalled. Finally, the use of weasel words is used quite widely in the field of pseudoscience. This is when conveyors of pseudoscientific beliefs use scientific-sounding words to trick people into thinking the data is legitimate. This was used in the Q Ray ad, stating that the bracelet was "ionized", which helped to "balance the energy" in your body. In reality, the bracelet was not ionized at all, and the creator admitted to just adding the word to boost sales. He didn't even know what ionized meant let alone how the process worked.
These are the tools with which we weed out the real truths from the baloney of pseudoscientific thinking. But Sagan warns that even the BDK can be used out of context and misused, so we have an obligation to be skeptical even to the BDK itself. One of our greatest tools is our own innate skepticism.