Robert Todd Carroll
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Skeptic's Dictionary Newsletter 25
May 5, 2003
(Previous newsletters are archived at http://skepdic.com/news/)
This issue of the Skeptic's Dictionary Newsletter--our 25th--marks our one year anniversary. We've grown from 258 subscribers to 2,064. At this rate, the entire world will be subscribed in about 3 million years. In any case, I am introducing a new feature with this issue: a brief critical thinking lesson (see below). Thanks to all of you for subscribing.
The Skeptic's Dictionary, the book
I received the bad news recently that the man most responsible for The Skeptic's Dictionary being published by John Wiley & Sons has been removed from his post as editor of Wiley's general interest line of books due to "reorganization." Jeff Golick supported the book when nobody else was interested in publishing it. He has been my editor for the past year and a half and I could not have asked for a better editor. I will miss working with him. Despite this setback, there will be no change in the publication schedule for the book. We're still looking at July as the month we launch.
New or revised entries in The Skeptic's Dictionary & Skeptic's Refuge
Since the last newsletter, I have
Beginning with this issue, I am going to devote a section of each newsletter to a lesson in critical thinking. The first lesson regards the difference between induction and deduction. It was inspired by an article in the most recent issue of the Skeptical Inquirer (SI) by Massimo Pigliucci on the same topic. I sent a letter based on the following to SI.
Massimo Pigliucci is certainly correct in saying that “it is important for anyone interested in critical thinking and science to understand the difference between deduction and induction” (“Elementary, Dear Watson” May/June 2003). However, it has been several decades since logicians have defined that difference in terms of going from general to particulars or vice versa. His own example of deduction belies the problem. It doesn’t go from the general to the particular but from one general and one particular statement to another particular statement. All men are mortal. Socrates is a man. Therefore, Socrates is mortal. General statements aren’t needed at all in the premises of some deductive arguments. For example, “Socrates is a stonemason. Socrates is a philosopher. Therefore, at least one stonemason is a philosopher.” This is a valid deductive argument. “Rumsfeld is arrogant. Rumsfeld is Republican. Therefore, all Republicans are arrogant” is also a deductive argument, though an invalid one, going from particulars to the general.
Induction, says Pigliucci, “seeks to go from particular facts to general statements.” That is true sometimes, but not all the time. Jones was late yesterday so he’ll probably be late today is an inductive argument. I admit it is not a cogent argument, but cogency is a different matter.
The general to particular relationship isn’t rich enough to serve as a good line of demarcation between induction and deduction. Any standard logic text today will make the distinction in terms of arguments that claim their conclusions follow with necessity from their premises (deductive arguments) and those which claim their conclusions follow with some degree of probability from their premises (inductive arguments). This distinction in terms of premises either implying their conclusions with necessity or supporting their conclusions to some degree of probability is not without its problems, however. One virtue of the general/particular distinction is that there is not likely to be any ambiguity about a statement being one or the other. But there will be many cases where it won’t be clear whether an arguer is claiming a conclusion follows with necessity. There will also probably be many cases where the arguer should be claiming a conclusion follows with some degree of probability but the language might well indicate that the arguer thinks it follows with necessity. For example, many people might argue that since the sun has always risen in the east, it is necessarily the case that the sun will always rise in the east. Yet, it isn’t necessarily the case at all. It just happens to be the case and it is easy to imagine any number of things happening to the earth that could change its relationship with the sun.
By dividing arguments into those whose conclusions follow with necessity and those which don’t we end up dividing arguments into those whose conclusions are entailed by their premises and those whose conclusions go beyond the data provided by the premises. A valid deductive argument can’t have true premises and a false conclusion, but a cogent inductive argument might. This may sound peculiar, but it’s not. Even the best inductive argument cannot claim that the truth of its premises guarantees the truth of its conclusion. Even the worst valid deductive argument--that is, one with premises that are actually false--can still claim that if its premises were true, its conclusion would have to be true. No valid deductive argument can guarantee the truth of its premises unless its premises are tautologies. (In logic, a tautology is a statement that cannot possibly be false: e.g., “A rose is a rose” or “Either it will rain or it will not rain” or “If Browne is psychic and stupid, then Browne is stupid.”)
So, how does knowing the difference between induction and deduction have any bearing on critical thinking? If you understand deduction, then you should be able to understand why scientific experiments are set up the way they are. For example, if someone claims to be able to feel another person’s “energy field” by moving her hands above the patient’s body, as those who practice therapeutic touch claim, then she should be able to demonstrate that she can detect another person’s energy field when that field is beneath one of her hands, even if her vision is blocked so that she can’t see which hand is over the alleged energy field. If one can detect energy fields by feel alone then one must be able to detect energy fields without the assistance of any visual or aural feedback from the patient. Likewise, if one claims to be able to detect metal or oil by dowsing, then one ought to be able to detect metal or oil hidden from sight under controlled conditions. If one claims to be able to facilitate communication from someone who is retarded and physically unable to talk or point, then one should be able to describe correctly objects placed in the visual field of the patient even if those objects cannot be seen by the facilitator.
On the other hand, the nature of induction should, at the very least, make us humble by reminding us that no matter how great the evidence is for a belief, that belief could still be false.
See also Austin Cline, Deductive & Inductive Arguments How do they differ?
Responses to selected feedback
Graham McDermott thinks there is an inherent flaw in the approach I take towards topics occult, paranormal, pseudoscientific, and supernatural.
Graham's point has an air of plausibility about only because it is based on two false assumptions. He assumes skepticism is a point of view rather than a methodological approach. And he assumes that I mold the data to fit preconceived beliefs. He also hasn't read my FAQ or the Introduction to The Skeptic's Dictionary. There is no need for a Believer's Dictionary because there has always been an abundance of supportive material for paranormal claims. What is needed is a counterbalance to all that pro-paranormal material.
Janice Mcgirt wrote about an experience she had with a person she worked with and asked for my thoughts on it.
My thoughts: She didn't know anything about your father. She hallucinated (had a vision) and you identified the hallucination as your father. The idea of a laughing man obviously reminded you of your father. Her hallucination pointed to his mouth. You related this to your father's deformity (rather than to the laughing). You provided all the detailed content to the hallucination. Donna just saw a man laughing who pointed to his mouth. (There are probably dozens of other things she might have seen that you could also have related to your father.) I don't doubt that Donna and many other people hallucinate (have visions). This is not normal and is a sign of some sort of brain malfunction and you were right not to laugh at or criticize Donna. She may think of her visions as a curse, a gift, or a nuisance, but however one looks at them, they are real to Donna. Visions become real to other people when they interpret them and give them meaning or significance, which is what you did by finding your father in Donna's hallucination. Of course I can't prove that Donna didn't see your father, but I think it very unlikely. What you did is something we humans are hardwired to do: find patterns. Something similar happens in sessions with mediums who claim the dead send them messages when they are ready to perform. They throw out the verbal equivalent of Donna's hallucination and somebody in the audience recognizes her father. As with your experience there is a deep emotional element in these experiences, which fortifies and validates them for the subject. The difference, of course, is that Donna doesn't claim to be psychic.
In the last newsletter, I mentioned a cult called The Pathwork and asked if anybody had ever heard of it. Chris Daniels responded:
According to Alta Vista, there are 6,297 links back to skepdic.com and 2,295 links back to skepdic.com (8,592 total). For comparison, Quackwatch (www.quackwatch.com) has 8,597 links to its pages and Michael Shermer's Skeptic Society page (www.skeptic.com) has 4,924. CSICOP has 10,427 back links and James Randi's Educational Foundation has 4,012. Sylvia Browne and James Van Praagh don't have 800 back links between them. Maybe the skeptics are more popular than we think! (To find back links for any site at Alta Vista search for link:http//"name of site" (e.g., link:http://skepdic.com).)
I did two interviews recently, one for a Belgian newspaper and the other for an Australian web site.
CSICOP is sponsoring a conference called "The Skeptic's Toolbox" from August 14-17, 2003, in Eugene, Oregon. I am going to try to attend but the fall term begins for me on August 18 and I am obligated to attend meetings on August 15. The reason I'm interested in attending this conference is that it will be covering exactly the same material as I will be covering in a new course I'll be teaching in the spring of 2004 called "Critical Thinking about the Occult and the Paranormal." I plan to teach basic critical thinking skills while having the students read books like Gary Schwartz's The Afterlife Experiments, Dean Radin's The Conscious Universe, Larry Dosey's Healing Words, and Tom Schroder's Old Souls: The Scientific Evidence for Past Lives. We'll be looking at the claims of each of these people that they have scientific evidence proving life after death, reincarnation, that prayer heals, or various paranormal claims. The CSICOP conference is going to examine a variety of paranormal claims allegedly supported by scientific research. Of course I already have my own ideas about the inadequacies of these studies. Nevertheless, I am sure I would find it beneficial to hear what the CSICOP experts such as Ray Hyman. Barry Beyerstein, and Wallace Sampson have to say about them.
Thanks to John Renish for his advice and editorial assistance.