Logical Fallacies

[PossumPie]

The thing that frustrates me most about debating anything is when people make errors in logic. We all do it. I decided to list some logical fallacies and examples of each in the hope that all of us (including me) will be more aware of them.

1. Argument from incredulity. This says "Because I can't believe something could possibly be true, then it isn't true."
Example: "I can't believe that the cops would miss finding a hatchet during their search, therefore it couldn't have been hidden in the house" or "When I look around I can't believe the earth is round, therefore it must be flat."

2. Post hoc Ergo Propter Hoc Argument: Latin for "After this, therefore because of this" It means that just because an event came before a second event, it caused it.
Example: "Every morning the rooster next door crows right before the sunrises...Therefore the rooster causes the sun to rise." or "Because the murders happened right after Morse visited, Morse must somehow be involved."

3. Argument from ignorance: a logical fallacy that claims the truth of a premise is based on the fact that it has not been proven false, or that a premise is false because it has not been proven true.
Example: "You can't prove Lizzie is guilty so she must be innocent" or "You can't prove Morse was innocent, therefore he must be guilty" This is sometimes called Russell's Teapot. Bertrand Russell once said that if he believed that there is a teapot orbiting somewhere between the earth and the sun, it can't be dis-proven BUT the burden of proof doesn't lay on you disproving it, but on him proving that it is there.

Unfortunately, this fallacy is very prevalent on this forum. People float wild theories, then say that because we can't DISPROVE their theory, it must be correct. BUT the burden of proof is actually on them to prove their own theory. Sadly most of the time they can produce no evidence whatever for their theory. I once facetiously stated that I believed the Pope had the Bordens killed, and challenged anyone to disprove it. Of course no one could, BUT logic says that the burden of proof wasn't on them, but on me to prove that the Pope did indeed have them killed. Theories that an illegitimate son killed Andrew or Morse hated Andrew and had him killed have not even a single shred of evidence of support, yet disbelievers are challenged to prove them untrue...

4.Straw Man Fallacy: A straw man Fallacy is an intentional misrepresentation of an opponent's position, often used in debates with unsophisticated audiences to make it appear that the opponent's arguments are more easily defeated than they are.
Example: "Evolution couldn't have happened. If humans evolved from monkeys, how come there are still monkeys around?" Evolutionists DO NOT believe that humans evolved from monkeys (only that they shared a common ancestor long ago) but Creationists argue that they do b/c it is easy to make that argument look foolish. or "People who think abortion should be banned have no respect for the rights of women. They treat them as nothing but baby-making machines." This misrepresents pro-life opinion which may have respect for women AND for the unborn. Just b/c they are against abortion doesn't mean they think women are just "baby machines" but that is an easy argument to win, so they misrepresent pro-life opinion.

5Argument from authority This is a tricky one. We SHOULD quote those in authority about the specific topic of debate, but just b/c someone touts themselves as "An authority" about a topic doesn't make it so. I sometimes fall into this fallacy, when I read a new book on Lizzie Borden, it always tend to sway my opinion. I believe that the author must "Know his facts" If I then see glaring errors in the book I realize that the author is NOT an authority on the Borden case. Throwing around authors' names in a debate is worthless unless the person is indeed a generally accepted authority on the case.
Example: A while back a person stating that she knew someone who knew Lizzie personally began posting here. I am NOT refuting her claims, only that many posters here gave her more weight in discussions because she supposedly was an "expert" BUT why? Because she said she was? There was no evidence of her authority at all.

6 Cherry-Picking This is a very, very common error. People pick only the facts that support their opinion, and ignore, or explain away other relevant facts that seem to disprove their opinion.
Example: Resume's are great examples of cherry-picking. We only put the positive things about us and our last jobs on a resume, and ignore the negatives. Politicians cherry pick. Pharmaceutical companies cherry-pick. They throw away 45 experiments that DIDN'T support their claim that a new medicine works, and published the 2 that do support the claim. On the Lizzie forum, Those who believe Lizzie is guilty disregard the fact that she didin't have blood on her, and focus on her motive. Those that believe Morse was guilty disregard that he had no motive and from all accounts genuinely liked Andrew and Abby, and focus on his 'coincidental' visit timing.

[Franz]

... "Because the murders happened right after Morse visited, Morse must somehow be involved."
...
because we can't DISPROVE their theory, it must be correct...

PossumPie, I appreciate your thread in general. If you speak only theorically, without reference to any discussion of the forum, it's all OK. If not, I would like to say some words only about the two phrases quoted above:

1. According to my personal reading experience in the forum (my threads included), I didn't see anyone who had expressed something like "Because the murders happened right after Morse visited, Morse must somehow be involved." Instead, more than one member think: "Because the murders happened right after Morse visited, Morse might somehow be involved."

2. According always to my personal reading experience in the forum (my threads included), I didn't see anyone who had expressed something like "because we can't DISPROVE their theory, it must be correct.", instead, more than one member think that "because we can't DISPROVE their theory,--- that is to say, if we can't prove a theory impossible -- it might be possible."

As I said, if you speak only theorically, it's all OK. But if you, in speaking so, made reference to any discussion of the forum, I doubt if you had committed an error stated by yourself in your thread, no.4:

"4.Straw Man Fallacy: A straw man Fallacy is an intentional misrepresentation of an opponent's position..."

(P.S.: I apologize if I had misunderstood you. I think our forum needs threads like one you posted here. )

[PossumPie]

You're right...but it is difficult to give examples. The authors of books and creators of theories DO IN FACT strongly believe that their theory is correct. Just look at how many lines of print you and I have exchanged typing our debates about your theory!!! You would have never wasted so much of your time defending a theory you didn't believe in.

Unless something else comes to light, we will never "prove" who did it. The facts we have available are NOT all correct. They are contradictory, and in some instances lies. As we debate the possible truth, we must remember to debate "logically"

[Curryong]

Does logic always rule these things though, Possum? In my years of following various cases of true-life crime I have seen people mount vigorous campaigns, and win through, in pursuit of justice, driven by tremendous emotion as well as belief in the person's innocence.
I do believe that a passionate belief in the case they were fighting took many famous advocates on to victory too. Yes, they had what they saw as logic and 'proof' on their side. I'm sure 'the other side' felt the same! But yes, I don't believe any of us will ever find out the truth about Lizzie's guilt or innocence. The passage of time alone has ensured that!

[Franz]

Does logic always rule these things though, Possum? In my years of following various cases of true-life crime I have seen people mount vigorous campaigns, and win through, in pursuit of justice, driven by tremendous emotion as well as belief in the person's innocence.
I do believe that a passionate belief in the case they were fighting took many famous advocates on to victory too. Yes, they had what they saw as logic and 'proof' on their side. I'm sure 'the other side' felt the same! But yes, I don't believe any of us will ever find out the truth about Lizzie's guilt or innocence. The passage of time alone has ensured that!

Yes, Curryong, you are right. But I think, the advocates use their logic to win a case; we are here to discuss freely the Borden case and attempt (God help!) to find the truth. In this forum we are not advocates of anyone. We do need to be objective and logical (I will try my best, PossumPie.)