What's your favorite logical fallacy?
- Thread starter Renata
- Start date
Than I believe you are like me, Col.
Hates when people relies on ignorance.
Yago
came undone
At Renata
I am a little bit confused now. You asked in your first post, next to other questions, kind a question:"What's you're favourite abuse of logic". My answer was the "locomitive-syllogism". It wasn't there to support any argument.
But back to the defintion problem (or premisse (don't know correct spelling in English)). One further problem is, that most premisses are normally taken for granted, that means, usually are not explicit covered in a post for example. They are important for the logical conclusion, but on a place like the internet, where a lot of different cultures communicate, are not known to a lot of others.
Like certain offensive gestures. In one country they are offensive, in another country fully unknown. Like the two-fingers set to the chin of the British. (Obviously, gestures are not important for the net, but I think they serve as good example for different premisses).
My statement still stands, when talking with people who have a lot of other premisses, i.e. people out of different cultural backgrounds, logic won't help, before premisses are taken care of.
And, I am not into natural science, if I remember correctly, there are lot of things, especially in physics, which work perfect, but are not proven. Can't be proven.
I am a little bit confused now. You asked in your first post, next to other questions, kind a question:"What's you're favourite abuse of logic". My answer was the "locomitive-syllogism". It wasn't there to support any argument.
But back to the defintion problem (or premisse (don't know correct spelling in English)). One further problem is, that most premisses are normally taken for granted, that means, usually are not explicit covered in a post for example. They are important for the logical conclusion, but on a place like the internet, where a lot of different cultures communicate, are not known to a lot of others.
Like certain offensive gestures. In one country they are offensive, in another country fully unknown. Like the two-fingers set to the chin of the British. (Obviously, gestures are not important for the net, but I think they serve as good example for different premisses).
My statement still stands, when talking with people who have a lot of other premisses, i.e. people out of different cultural backgrounds, logic won't help, before premisses are taken care of.
And, I am not into natural science, if I remember correctly, there are lot of things, especially in physics, which work perfect, but are not proven. Can't be proven.
Dralix
Killer of threads
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I guess I'm partial to affirming the consequent. I think it's very important to debate using proper logic. In fact, I would say it's essential. If I go around affirming the consequent, or arguing with an undistributed middle, then I'll look quite the fool. The easiest way to convince me of that would then to point out the flaw in the logic. With mastery of logical arguments, you don't even have to consider the substance of the argument to shoot it down.
Of course I've forgotten most of what I learned since I took logic some 10 or 12 years ago. Every now and then I want to read my text again not just to refresh my memory, but because I found the subject matter very interesting.
Of course I've forgotten most of what I learned since I took logic some 10 or 12 years ago. Every now and then I want to read my text again not just to refresh my memory, but because I found the subject matter very interesting.
My apologies. Looks like I linked two things in your post that weren't meant to be linked.
Agreed.
If you read anything on the scientific method, generally the authors will go out of their way right up front to emphasize that science can never prove *anything*. What it can do is provide evidence to support a theory -- enough evidence in favor, and the theory is treated essentially as fact --- it's considered to have been proved 'beyond a reasonable doubt', in US legal terms --- but scientists are supposed to realize that a single contrary observation, properly verified and supported, could still tear the whole thing down.
In practice, though, this hardly ever happens, since theories are generally so complex that any particular observation only addresses part of it. If the observation proves to be true, then that part of the theory is revised, but the theory as a whole doesn't need to be discarded if the the evidence in favor of the rest of it is still valid.
So I still take issue with calgacus' assertion that all of science is simply a 'post hoc ergo propter hoc' fallacy, since my understanding of the fallacy is that it comes into play when a debater implies causation due to placement in time *in the absense of other evidence to support the claim.* Science is all about gathering that other evidence. But maybe we have a definitional problem.
edit regarding the above: And yes, I do think Hume was *ahem* arguing 'a posteriori' in this case, because I do believe that inductive arguments are valid given enough evidence in their favor. A thing that can't be proven deductively isn't automatically untrue, IMO, just unprovable deductively.
Renata
Pangur Bán
Deconstructed
The important point is the absence of necessary connection. We make the connection upon based on our experience, all that Hume is saying is that we do invent the connection. There is nothing which shows a necessary connection between cause and effect. Hume pointed out that we observe one event following another and, with more and more observation of this occurence, we conclude that the one event caused the other. That is a case of post hoc, ergo propter hoc not matter how you look at it. 
Serutan
Eatibus Anythingibus
The school of logic exemplified by:
If one woman can have a baby in 9 months, the 9 women could have a baby in 1 month.
And the the All-American one: To save money, you have to spend it.
If one woman can have a baby in 9 months, the 9 women could have a baby in 1 month.
And the the All-American one: To save money, you have to spend it.
insurgent
Exhausted
In Denmark, we once had a famous theatrical author called Holberg. He wrote about a man returning to his old and ignorant village after visiting some fancy university and acquiring a whole lot of knowledge. When he returns, his family and friends laugh at him and his claims, such as the earth is round. A counter-argument against him by his brother has become a famous line here:
"Mother can't fly. Rocks can't fly. Thus, mother is a rock."
Of course this is false, and is a false syllogism. It's from the play "Erasmus Montanus".
Does anybody know the specific rules for valid syllogisms? I haven't been able to find any good rules, to avoid stupid conclusions such as the one above (except for a long explanation in Latin - which isn't very useful).
"Mother can't fly. Rocks can't fly. Thus, mother is a rock."
Of course this is false, and is a false syllogism. It's from the play "Erasmus Montanus".
Does anybody know the specific rules for valid syllogisms? I haven't been able to find any good rules, to avoid stupid conclusions such as the one above (except for a long explanation in Latin - which isn't very useful).
yeah - a lot of books have them in the form
All A is B, All C is B therefore A is C
If A then B, B therefore A.
(Both are examples of faulty logic!)
All A is B, All C is B therefore A is C
If A then B, B therefore A.
(Both are examples of faulty logic!)
Originally posted by calgacus
The important point is the absence of necessary connection. We make the connection upon based on our experience, all that Hume is saying is that we do invent the connection. There is nothing which shows a necessary connection between cause and effect. Hume pointed out that we observe one event following another and, with more and more observation of this occurence, we conclude that the one event caused the other. That is a case of post hoc, ergo propter hoc not matter how you look at it.
Well, Hume is a twit.
Now there's some logic for you.
Edit: Just thought of an example of post hoc ergo propter hoc that never fails to get me to tear my hair out: stock market reports.
Brain-dead anchor: The stock market fell today on reports that crude oil prices are rising.
Me: But if the stock market had risen today you'd have said it was due to the good earnings reports released by major drug companies, right?
Aaaaaaarrrrrrrgggggghhhhhhhhhhh!!!!!!!!!!!
Renata
Pangur Bán
Deconstructed
I'm not sure how to interpret your post, Renata. 
nihilistic
Intergalatic Delivery Boy
List of Classic Paradoxes
The Lie
This sentence is false.
Russel's Paradox
Consider the set of all sets that are not memebers of themselves.
Achilles' Race
Achilles cannot run a lap around the race course because he must first reach the halfway point between his starting point and the finishing point, then he must reach halfway between the aforementioned halfway point and the finishing point, then he must reach the point where he is 1/8 the distance from the finishing point, 1/16, 1/32 .... There is an infinite number of tasks Achilles must complete before he reaches the finishing point. Hence, he cannot finish.
A Heap of Sand [Slippery Slope]
A grain of sand is not a heap of sand. If any amount of sand is not a heap of sand, then adding one grain does not make it a heap of sand. Repeat this for a hundred thousand times, and you have that a heap of sand is not a heap of sand.
The Surprise Exam
A professor announces that a surprise examination will be given sometime next week. A student claims that there is no test.
I'm sure there is more, but that's all I can remember.
The Lie
This sentence is false.
Russel's Paradox
Consider the set of all sets that are not memebers of themselves.
Achilles' Race
Achilles cannot run a lap around the race course because he must first reach the halfway point between his starting point and the finishing point, then he must reach halfway between the aforementioned halfway point and the finishing point, then he must reach the point where he is 1/8 the distance from the finishing point, 1/16, 1/32 .... There is an infinite number of tasks Achilles must complete before he reaches the finishing point. Hence, he cannot finish.
A Heap of Sand [Slippery Slope]
A grain of sand is not a heap of sand. If any amount of sand is not a heap of sand, then adding one grain does not make it a heap of sand. Repeat this for a hundred thousand times, and you have that a heap of sand is not a heap of sand.
The Surprise Exam
A professor announces that a surprise examination will be given sometime next week. A student claims that there is no test.
I'm sure there is more, but that's all I can remember.
Pangur Bán
Deconstructed
nihilistic, open a thread on paradoxes, it'll be fun 
Originally posted by calgacus
I'm not sure how to interpret your post, Renata.
Hmm? I was being silly, guess it didn't come through. We seem to disagree on the nature of inductive 'proof' - you take the philosophical view as exemplified by Hume, I take the scientific view. Not a problem for me, and nothing worth arguing about. I just felt like putting a period to the end of that little mini-discussion and chose to do so with yet another logical fallacy, which I thought fit well with the thread.
And then later, with logic still on the brain, the stock market thing occured to me, so I edited the post to add that.
Renata
Double Barrel
Deity
A good friend of mine always argues with me that "anything is possible". For instance, a pink elephant could be on the other side of that wall. I say, not. But he says that I'm not there so it is possible. Auuurgh!! Now I counter with probability, which he has to answer with a very low probability that the pink elephant is on the other side of the wall. This goes round and round.
I do the same thing with UFO believers. Having never experienced a UFO, or even spoken to someone that has (its always the account of a friend of a friend of a third cousin), I seriously doubt the existence of UFO's. Sure, it is possible, but just improbable in my book.
Is there a name for this kind of logic? Or is it not logic at all?
Also, what about the "all rules are made to be broken" rule?
I do the same thing with UFO believers. Having never experienced a UFO, or even spoken to someone that has (its always the account of a friend of a friend of a third cousin), I seriously doubt the existence of UFO's. Sure, it is possible, but just improbable in my book.
Is there a name for this kind of logic? Or is it not logic at all?
Also, what about the "all rules are made to be broken" rule?
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