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Some that I forgot:
Straw man argument: conflation of opponent's argument to make it easier to challenge.
Appeal to authority: assumption that a claim is correct because an authority figure supports it.
Appeal to popularity: the assumption that a claim is correct because a large amount of people support it.
Argument from faith: the assumption that a claim is true because the interlocutor believes it to be so, regardless of evidence.
Special pleading: exempting a particular claim or premise from the same scrutiny as another to preserve an argument's validity.
Now that Jared has listed fallacies in informal logic it might be useful to apply them to some of the more commonly used religious apologetics.
I'll start us off with the argument from apparent design or teleological argument. We'll start with Aquinas.
"The Teleological argument is founded on Aquinas's fifth way:
1. All natural occurrences show evidence of design
2. This suggests that there is a being that directs all things
3. Things that lack knowledge cannot achieve anything unless directed by a thing with knowledge
4. There is therefore an intelligent being that directs everyone towards a purpose
5. For Aquinas, this being is God
1. So straight away we see in 1 the common logical fallacy of begging the question, by asserting the very thing he's arguing for in the argument, namely design in nature.
2. Here he's using argumentum ad ignorantiam, the fact there is an inexplicable appearance of design he couldn't explain has been used to imply a being. Note he was wholly unaware that complexity of all living things is fully and naturally explained by evolution.
3. Begging the question again, since has is asserting in his argument the very thing he is arguing for.
4. The conclusion of course is fallacious because the premises it's based on are demonstrably irrational. However we should also not the way the conclusion simply assumes that complexity and knowledge indicates purpose as well as design. Again this is begging the question.
5. Nothing needs to be said here as this is begging the question as it is pure assumption of the thing he's arguing for in his argument.
I might get shot down for using antiquated apologetics here, but please bear in mind that Aquinas's 5 ways was cited by two different theists in the EVIDENCE thread I started, as "objective evidence" for the existence of a deity.
Thank you, I am stealing this for future reference and possible (definite) plagiarism.
* Changes into black and white shirt and black eye scarf, tiptoes away and adds to squirrel like hoard of good stuff *
The best example of a straw man argument is Willaim Lane Craig insisting atheists 'must' believe something can come from nothing.
It's usually followed up by a false dichotomy where he insists explanations for the origins of the universe are limited to either a deity or the above straw man argument. Since we dont know how the universe originated he can't know what our options are or how many there are, that's axiomatic.
Also note Craig's inclusion of a deity as one possibility without a shred of evidence and again in an argument for that deity, so begging the question again.
The Argument from Bullshit. "My pastor told me..."
The Argument from Imagination, "If" (Anytime you hear the word "if" you have entered the realm of imagination.,
The Argument from "Yabut." (Yea But) -- No no no no..... there is no but. Address the issue.
One more common logical fallacy is post hoc ergo propter hoc, or after this therefore because of this. Where causation is assigned to a preceding event without evidence.
This is most commonly used to fallaciously validate prayer. Where a prayer is made and the result is favourable and the prayer is cited as the cause without any evidence.
This often uses the sharpshooter fallacy as well, its a selection bias where only the "successful" prayers are cited after the event, and the failures are ignored.
"The cranial-rectal fallacy." Sorry, my head is up my butt and I can't hear you.
Your list of fallacies was outstanding--and useful! Hope you don't mind if I do some heavy-duty editing to pull it all together, including contributions from Sheldon, Irving Copi ("Introduction to Logic" 7th edition) and other sources. I hope to make it as clear and useful as possible rather than technical. A comprehensive list would have to cover way too many examples, but there are no doubt a few popular items that I missed that should be included--a job for later editing.
Ad hoc (For this purpose only): The fallacy of advancing, without evidence, a claim designed solely to save an argument from some criticism. (A loophole is appealed to without justification. Example: The story of Peter's denial of Jesus has the campfire in two different places--a contradiction! No it isn't, says the Bible-believer, because there were really two campfires! But, there is no biblical evidence for that and, indeed, the scenario becomes positively awkward.)
Appeal to authority: A fallacious argument asserting that a claim is correct because an authority figure supports it. (Example: Dr. so and so has written a thick book filled with equations that proves that the sun goes around the earth. So, the Earth doesn't go around the sun! Uh, maybe we should actually take a close look at those arguments! Quoting authority figures simply bypasses the reasoning process, and any debate is all about facts and reasoning. However, quoting recognized authorities can be a good way to show where the scientific community stands on an issue. That does carry a lot of weight even though it is not an argument per se. It can also be a good way to present professional explanations of concepts and terms used by experts in some field.
Appeal to Ignorance: The fallacy of claiming that if the opposition can't prove its case then our case is true by default. (Perhaps more evidence will come in and the opposition will prove its case! The opposition may be incompetent. Both cases may be wrong! Example: If Johnny can't prove he didn't harass Jane, then he must be guilty!)
Appeal to popularity: An attempt to win an argument by noting that almost everyone supports it. (Way back in the bad, old days it was a great way to prove that the world was flat!)
Appeal to Tradition: An appeal claiming that an action or conclusion in accordance with long-established customs is best. (Example: Women should be good housewives because that has always been the natural order of things.)
Argument from Ignorance (Argumentum ad Ignorantiam): The fallacy of advancing a claim on the basis that no one has proven it false. (Examples: Prove that God doesn't exist, says the believer, or else admit that I have a good case. Prove that Zeus doesn't exist or I have a good case! On this basis we could make a good case for all kinds of things, including the Great, Green Spider who lives in the clouds of Jupiter and rules over the Solar System. Obviously, this is no way to reason.)
Argument from Memory: The fallacy of relaying personal memories as factual. (Studies have shown that memory is influenced by a huge number of factors, is reworked, and is therefore unreliable. Memory is anything but a securely stored video tape.)
Argument from Personal Incredulity: The claim that if an idea makes no sense to us then it must be nonsense. (Example: I can't even imagine how the blind forces of evolution could have possibly created that complex factory called a "leaf." The idea of evolution is just so absurd! But, nature is hardly required to accommodate educated (let alone uneducated) opinions as to what is reasonable. The universe and mathematics is full of deep subtleties that defy common sense.)
Begging the Question (petitio principii): The fallacy of borrowing from the conclusion in order to reach the conclusion, or assuming that which must be proved (the conclusion or part of it). (Example: Natural laws don't apply to God's superpowers and are, therefore, not an argument against God. God's supernatural powers, and therefore God, are assumed to exist. The conclusion is that God's existence is not threatened by natural law. Of course God's existence is not threatened by natural law--or anything else--if we start by assuming that God exists! The real question is whether a being with superpowers is a reasonable conclusion based on the data (natural laws). Often Begging the Question and Circular Reasoning are used synonymously.)
Circular Reasoning: "A" proves "B" and "B" proves "A". (A perfect circle of reasoning going nowhere! Example: The Bible proves that God exists. How do we know that the Bible is right? God wrote the Bible! But "B" is our conclusion, and we cannot use it to support "A"--thereby using "B" to prove itself! Often Circular Reasoning is just another name for Begging the Question, but I like to think of Circular Reasoning as a special case where the conclusion is used whole hog to prove itself.)
Equivocation: The fallacy of equating different definitions of a word throughout an argument to support the conclusion. (Example: A creationist quotes a famous scientist who refers to biological evolution as a theory. "See," the creationist cries, "evolution is merely a theory and nothing more!" The conclusion is that evolution is bunk, a conclusion reached by applying the common definition of "theory" (guesswork or half-baked) to the scientific definition (an idea that has been well tested, explains a whole bunch of related data, is fruitful in generating further research, and that fits in well with other theories). Dishonest creationists count on the fact that most people are woefully short on science and probably don't know the difference.)
False Dichotomy: The fallacy of limiting the outcomes to "A" and "B," arguing that "A" is false, therefore "B" must be true. (Example: Either life arose by evolution or by a creator, God. Creationists then "refute" evolution. Therefore, God must exist! Overlooked, for instance, is the logical possibility that some other natural process might have gotten life started, or that a committee of gods got it started and later died.)
No true Scotsman: The fallacy of defending an accepted, universal generalization from harsh counterexamples by simply switching definitions. (Example: Real Christians would never commit the gross, horrid crimes carried out by the medieval officials of the Church, so those people were not true Christians. Thus, you can't impugn Christianity on their account. In one stroke all bad Christians have been defined out of existence! Christians are normally defined as people subscribing to the doctrine that Jesus was crucified, resurrected, and offered eternal salvation to those who believe in him. Suddenly, the definition gets changed to eliminate all bad Christians!)
Non Sequitur (Argumentum non sequitur): A conclusion that bears no logical relationship to the argument. ("Non sequitur" often gets applied to conclusions whose support bears little or no resemblance to rational arguments.)
Post hoc ergo propter hoc (after this, therefore because of this): If "B" follows "A," then look to "A" as the cause of "B." (Example: Seven kids came down with a serious illness after getting their vaccination shots. Therefore, the vaccination program should be immediately terminated. But, what if those kids lived in five different states and that seven million kids got their shots without any problems? Might we be dealing with other, random causes that bear no relationship to the vaccination program? How many people have a serious auto accident within three weeks of buying a shiny, red car? I suspect we could find at least seven people if we really plowed the data. Should we conclude that buying a shiny, red car is dangerous to your health? Day always follows night; should we conclude that night is the cause of day?)
Slippery Slope: The fallacy of claiming without probable cause that the triggering of one event will trigger a chain of events, the last one being clearly unacceptable. Therefore, the first event should be avoided. (If any of the links are dubious, or if the chain as a whole is unlikely, then the conclusion does not follow.)
Special pleading: Arguing, without proper justification, that the usual rules be lifted for a particular case. (Example: An administrator asks a professor to pass Sayeed even though he failed his math class. "Jack," the administrator pleads, "They will crucify him back in Saudi Arabia if he returns with an "F" and he is a really nice kid. Besides, Saudi Arabia may fund one of our programs and I don't want any problems!" Such arguments, however, are irrelevant with respect to the rules for assigning grades. Accepting such an argument may be a wise choice, but it can never be a logically reasoned conclusion.)
Straw man argument: An attempt to beat the opposition by attacking a much softer, false version of their argument. (Example: Because it deals with blind chance, evolution is no more probable than a tornado sweeping through a junkyard and producing an airplane. But, a lot more than random chance is involved!)
I've sometimes thought about the logic of fallacies. I think it'd be a great research question to ask why we make them at all. As in why we think they're right. Us being a thinking, reasoning species, there is bound to be logic to our errors. It isn't ignorance or stupidity that makes people make these fallacies.
For example the ad hominem argument makes sense. Why would I believe you, when you have a track record of being a liar?
"Us being a thinking, reasoning species"
Logic is anathema to how we think, we use logical fallacies all the time precisely because that is the case. Logic is a method of reasoning humans have created that adheres to strict principles of validity. If our natural reasoning processes had logic in it's errors we'd not have needed to create logic. There's a reason we use science for things like medicine and technology rather then superstition.
"For example the ad hominem argument makes sense. Why would I believe you, when you have a track record of being a liar?"
Now that is a fallacious example, since it is not the only form of ad hominem, so might have better said ad hominem attacks are not always fallacious, but then logic doesn't claim it is, so you're quite simply wrong here. It's an ad hominem fallacy if it is irrelevant to the argument under scrutiny. How is someone being an habitual liar irrelevant to whether you trust their opinion on something? If they offer an argument then I'm not sure habitual duplicity is relevant then it can be assessed on its own merits, likewise evidence can be examined and subjected to critical scrutiny.
An argument that contains fallacious logic cannot be rationally asserted as true. I think your objections here have more to do with how often religious argument contain them. I'm going to go with logic until your objections are validated by the best philosophical minds and they reverse thousands of years of logic and rational thinking, just as I'm going to accept scientific facts like evolution until creationists objections are validated by science.
"Logic is anathema to how we think, we use logical fallacies all the time precisely because that is the case."
I think anyone familiar with cognitive psychology knows that isn't the case. The brain is an information processing machine, and it processes information in specific ways and for specific purposes. One of the first things we learn about logical thinking is that it is significantly easier to test the validity of a conclusion, if the syllogism is using concrete rather than abstract language.
If I aske people whether the following syllogism is valid, the majority get it wrong:
If I study, I’ll get a good grade.
I got a good grade.
Therefore, I studied.
But if I keep the structure the same, and swap out the words for something more concrete, almost nobody has problem seeing why its wrong:
If I live in Tucson, then I live in Arizona
I live in Arizona.
Therefore, I live in Tucson.
Logic is definitely not anathema to how we think; and even when we make errors, they are made for reasons which make sense.
"Logic is anathema to how we think, we use logical fallacies all the time precisely because that is the case."
I think anyone familiar with cognitive psychology knows that isn't the case.
>I'd like a few citations from prominent bodies of psychology that support your claim that logical fallacies are in not in fact fallacious, otherwise I'm inclined to use Hitchens's razor here.
"One of the first things we learn about logical thinking is that it is significantly easier to test the validity of a conclusion,"
>I don't think it's easier at all, and anyone who doubts this pick up a book on formal logic, and just start reading, without someone who understands it and can explain what it means I'd be stunned if you could make any sense of it. The first thing we should learn about logic is that though it is difficult and counter intuitive it is far more successful at testing the validity of a conclusion.Informal logic is no less counter intuitive though is a lot simpler, and this is reinforced by the fact that we commonly use reasoning that is fallacious, hence the term "common logical fallacies". They're called common for a reason I'd have thought.
"Logic is definitely not anathema to how we think; and even when we make errors, they are made for reasons which make sense."
I disagree, hence the ancient Greeks realising our thought processes are often fallacious, and listing the most common ways this happens. Unless the principles of logic have changed overnight and common logical fallacies are no longer considered to be fallacious of course, I'm guessing this is not the case though.
Actually I'm not guessing at all, I've checked all the major news channels and looked online. Just as your opinions on scientific facts like evolution are at odds with the scientific world because your beliefs are at odds with evolution, so your opinions on logical fallacies are at odds with the principles of logic, again obviously because religious apologetics so often uses and is based on fallacious logic. I sympathise but you're simply shooting the messenger.
Either religious claims that use common logical fallacies are irrational and the arguments invalid, or the principles of logic are wrong, I'm inclined to believe the former based on the best objective evidence. Though as always I shall remain open minded and keep a weary eye on the news.
OK, I got one for you (and anyone else who wants to try): which of the following statements (A, B, C, D) are true:
Perhaps I'm overthinking it, but none seems true. Maybe A? They all seem half baked.
A, C, and D are true.
B is false.
logic is a nasty business :)
I'm also curious if you're able to ask the same question again, but without the abstractness of numbers?
In the same order (A, C, and D are true, B is false):
Could you provide an explanation for this, or a link that would take me to one? I'm very curious the reasoning behind this, and I've had a hell of a time trying to figure it out from looking at it.
Well don't feel bad, I specifically choose this one because it is rather counter-intuitive.
It is often presented in the general form:
If p, then q. or sometimes as p → q.
p is called the antecedent, q is called the consequent. The important part to understand is, the full statement can only be false if p is true, and q is false; in all other cases it is true. Let's try a real world example:
If you come to my office tomorrow, you will get a candy bar.
The question is, is what I said true or false? There are 4 possible cases:
Again, if the antecedent is false, it matters not what the consequent is, we already know the statement is true.
If 5 = 6, then 7 = 8.
Since the antecedent (5 = 6) is always false, it doesn't matter what the consequent is, the statement is always true.
Humph. Now I need some ibuprofen.
heh sorry about that. But yeah, this is a particularly nasty one.
Part of what makes it nasty is that in logic there are two different versions of if. That is "if" and "if and only if". But in common speech we use "if" to represent both cases (which leads to all kinds of confusion).
Jeeze, just when I think I am getting a decent handle on this whole logic thing... I even taken a class on logic...
I think your examples were just bad examples, hence why they felt half baked. It doesn't make sense to simply state a condition and ask if its true. Conditions are by default presumed to be true. Moreover, syllogisms exist within their own bubble; it only matters if a conclusion follows from the premises, not if the premises are true in reality. When you say 5 = 6, I have to assume thats true. If you're saying its false because in real life its false, then why on earth would you say 7 = 8 is a true statement?
Your office example seems completely out of touch with your original example.
The fact that you think 5 = 6 could possibly be true; scares me.
I never said 7 = 8 is true. It isn't true. That is the point of it. It is something we can be sure is false.
It has the same form: if p, then q
Didn't I just make the distinction between what is true in reality versus within a syllogism? In other words, the difference between a syllogism being true, and being valid. Not sure what should scare you if you comprehended what I said.
In your example, you called this a true statement: "If 5 = 6, then 7 = 8"
Can you not see the difference between them?
7 = 8 is always false. This one is as obvious as the nose on your face.
If 5 = 6, then 7 = 8 is always true. This one is tricky, and if you can't see it, it is OK. Almost every gets it wrong the first time they see it. But I assure you, it is always true. Any mathematician or logician will give you the same answer. I already linked the truth table for it showing it is true. You can even put it into a calculator and try it.
If 5 = 6, then 7 = 8
If 5 = 6, then 7 = 9
Are those both true statements, and if so, are they not contradictory?
Both of those statements (A and B) are true. There is no contradiction present. If you incorrectly believe there is a contradiction, please express it explicitly.
Again, check the truth table below. Both A and B are the 4th entry in the truth table below.
Again, this is not something that comes from me. This is introductory level material in the field.
I'm not entirely au fait with this myself, but I think what he's misunderstood is that the statement says if not if and only if. If it were the second distinction then they could not both be true I think.
I apologise if I've got this wrong, but beyond recognising commonly used fallacies in informal logic I'm out of my depth.
However your examples prove the point I was trying to get Breezy to understand earlier, that rationality and logic are very much counter intuitive to the way humans think. Hence the common in common logical fallacies. If we aren't aware of these and the consequences of using them, or if we dont understand them and the consequences of using them, then we won't realise we're making fallacious arguments.
Religious apologetics nearly always use these common logical fallacies. What's surprising to me is when "professional " philosophers like William Lane Craig use them and stick with them for debate after debate. Until I researched where he studied and it can't be a coincidence they were religious institutions rather than secular universities.
I'd guess you are pretty close to the mark.
In logic, mathematics, statistics, computer programming, etc: we use
IF AND ONLY IF. They have very different meanings and have different truth tables. In casual speech we use
IFto represent both, confusing the shit out of people.
Yes, that is why I love this example: it is extremely counter-intuitive (imo). I don't think I know anyone who got it right the first time; I sure as hell didn't.