Fallacy and Conclusion

Question

Idk where else to ask so sorry if I am wrong to ask here...But this place seems fitting.

A Fallacy, both formal and informal is/are error in the reasoning to reach a conclusion for an argument/point/belief. Yet, if you assume that conclusion is wrong because it have fallacy, that in itself is wrong and fallacious, specifically "Fallacy Fallacy".

But what if it's the other way around? What if people assume that since the conclusion of an argument or a point or a logic is wrong, there must be a fallacy?

For example take this

1. Cyanide is a poison
2. This drink have Cyanide in it
3. This drink is poisonous.

Now this is sound and valid. However you can make it sounds like it is fallacious. For example; assume that there is a drink with Cyanide on it but also brewed in a way that makes it non-poisonous. That would imply this conclusion of this set is wrong. But is it fallacious? what if the person who made this set just didn't know that non-poisoned-Cyanide-drink exist? Assuming such drink did exist that is.

Another example.

1. This hot chocolate is made of vegetable; chocolate
2. Vegans only drink vegetarian beverage
3. This hot chocolate can be drunk by Vegans

This is actually true in some cases, and not true in some cases. Some hot chocolate may have milk which is not vegetarian. If a vegan is given a hot chocolate with milk, and that person didn't know there is milk, nor ask, that vegan is wrong but is it fallacious? However it is also possible that the vegan is given a hot chocolate without milk.

In both cases, there is a lack of information that may make their logical conclusion to be false. And sometimes it's actually quite rare for the exception to that logic to exist, such as the Cyanide example. While you can say that their fault is due to their lack of information, I don't think it is fair to immediately blame someone for lack of information for something that can be taken at face value, such as those that involves "Rule of Thumb". It is quite unrealistic to demand someone to know everything about anything about beverages to make simple judgement such as drinking a drink. That doesn't change that they can be wrong though.

Yet another example, when you order a juice at a restaurant, and then you are given the juice you ordered. You "assume" that the juice is safe, turns out the juice is poisoned. That means the conclusion is wrong, yet does that means there is fallacy in your judgement? It's quite unrealistic and overreaction to doubt every drink given to you just because there is a small chance it can be poisonous. So I don't think there is any fallacy here despite the premises here are all logically true and valid.

I don't think simply having the wrong conclusion means there is an error in the reasoning for it to be fallacious, yet I don't see anyone talk nor there is article about it. So I am curious what other's think.

What do you guys think? Can something have true premise(s), but wrong conclusion and yet no fallacy? Is it fallacious to assume that because the conclusion of point/belief/argument is wrong, there must be a fallacy? If so...What is the fallacy called?

Answer 1

There are two errors that can be identified in these arguments. I'm not sure whether they count as errors in formal logic.

Consider this example:-

1. This hot chocolate beverage is made of vegetable; chocolate
2. Vegans only drink vegetarian beverage
3. This hot chocolate can be drunk by Vegans

I've tidied up premiss one because it could be thought to be ambiguous between the contents of the tin and the contents of the beverage.

The first error is well known; it is called a suppressed premiss:-

2a. There is no ingredient other than chocolate in this beverage.

If the other error has a name, I do not know it. It is that premiss 1 turns out to be only partly true. It should read:-

1. This hot chocolate beverage is made of vegetable; chocolate, and nothing else.

In your first argument premiss 2 should read:-

2. This drink have Cyanide in it, brewed in a way that makes it non-poisonous.

You don't need to make both changes to each argument. One or the other will do the job.

I don't think there is any way to formally guarantee that a given argument does not contain these errors if any of the premisses is empirical.

If you are formulating an argument in real life, there is an expectation that you will exercise reasonable care to ensure your premisses are complete and wholly true. If you have done that, you are not to blame for any errors.

Yes, it would be unreasonable to doubt every drink given to you because there is a small chance it is poisonous. You are entitled to count on the person you buy the drink from that they have given you accurate information about it - and that person is entitled to count on manufacturer's information as true and complete.

Answer 2

For example take this

Cyanide is a poison

This drink have Cyanide in it

This drink is poisonous.

Now this is sound and valid. However you can make it sounds like it is fallacious. >For example; assume that there is a drink with Cyanide on it but also brewed in a >way that makes it non-poisonous. That would imply this conclusion of this set is >wrong. But is it fallacious? what if the person who made this set just didn't know >that non-poisoned-Cyanide-drink exist? Assuming such drink did exist that is.

Your initial argument rests on the premise that Cyanide is a poison. If you now assume that there is a drink with Cyanide on it but also brewed in a >way that makes it non-poisonous, then you are falsifying the premise that Cyanide is a poison since it now depends on whether it is or not brewed in a >way that makes it non-poisonous. Adding a new premise changes the argument. In other word, if you add a premise, it is a different argument. In this instance, we all see the initial argument as valid because we all assume that a poison is always poisonous. Your new premise means that a poison remains a poison even though it is possible to make it non-poisonous. However, if we accept this premise, the new argument is clearly fallacious:

Cyanide is a poison

Cyanide can be brewed in a way that makes it non-poisonous

This drink has Cyanide in it

This drink is poisonous.

The drink is not necessarily poisonous if the premises are all true.

Answer 3

If the conclusion follows from the premises then true premises necessitate a true conclusion so if that is not the case it's a fallacy. As the truth of the condition is not a consequence of the premises (either because they don't determine it or because there are non-stated factors that contribute to determining it).

In the example with the cyanide the fallacy is, as others have mentioned, that there is a hidden premises of "mixing a poison with another substance preservers the poisonous quality". Which isn't necessarily true, like if you mix a poison and it's respective antidote would not be poisonous.

The other relevant point here is that poisonous effect doesn't follow from the presence of a poison to begin with. It depends on the dose, the person who takes it, their immune system and general constitution and so much more. So it's not even valid to begin with that consuming a poison is poisonous.

While if you use a non-standard definition of anything with added poison is poisonous then even brewing it so that it loses it's effect would still mean it's poisonous (as it still contains a poison).

And the 2nd example is essentially:

Hot chocolate is vegetarian
Vegans only consume vegetarian food
Vegans could consume hot chocolate

The problem is that while the first 2 statements are true that does not necessitate that the conclusion is true. Like the obvious problem is that vegan is a subset of vegetarian so a vegetarian could eat all that a vegan could eat but not the other way around.

So for it to be valid, it would need to be:

vegans could eat everything that is vegetarian
hot chocolate is vegetarian
Vegans could eat hot chocolate.

That would be incorrect but it would valid. The fist isn't even valid as the relation between vegan and vegetarian isn't stated in the argument, yet is what the success or failure of it relies upon.

Answer 4

@FlippeRFlappeR, I believe @Ludwig V is spot on. If an argument is valid and its premises are true then, the conclusion is necessarily true.

This means if the conclusion is false,

1)the argument is invalid

and/or

2. the premises are false.

Fallacies are, to my reckoning, about invalidity and so look at possibility 2 (false premises). It is possible that an argument 1) is valid (nonfallacious) 2) can have a false conclusion because the premises are false.

For example look at this argument:

1. If Dogs are fish then dogs have gills

2. Dogs are fish

Ergo,

3. Dogs have gills (1, 2 modus ponens)

The argument is valid (modus ponens) i.e. it isn't fallacious but it has a false conclusion (dogs have gills), just the kinda situation you were describing.

Answer 5

After reading every answers, I've gained new knowledge. Ironically, my new knowledge only strengthen my belief. I know this sounds like self-righteous, but that is truly what I think after searching.

Thanks to Joseph I've start to look more towards Formal and Informal logic and how they apply for real world logic. Thanks to Ludwig I've search internet more for "Mistakes". Like Joseph said, in formal logic it is not fallacious to say "If there is a wrong conclusion, there is a fallacy" but in real world logic, it may be fallacious to say so. Mistakes happens, that is human nature.

There are intentional and unintentional, and Fallacy is intentional. Factual Mistakes for example is not inherently a fallacy. It could be a misconception which is similar to False Premise, or it could be another unintentional mistake. For example if you search for Factual and Logical mistake online, you will get an example of counting 20 people in a room when in reality there is 21. That is factual mistake not from False Premise but rather a Factual Mistake from miscounting.

A misunderstanding can happens due to a Fallacy, and a Misunderstanding itself can cause a fallacy, but is it in itself a fallacy? Misunderstanding can be due to a lot of things, like in my bachelor example. Fallacy is Error in Logic, Misunderstanding can happens due to correct logic just not in line with the other person, or due to language barrier. I don't understand how could someone said Misunderstanding is a fallacy...

There is also the case of forgetting something can make us make a mistake. I hope people don't think forgetting something is a fallacy either...

But this question has actually does convince me that people do think Wrong Conclusion means Fallacious argument. A "Fallacy" is a mistake but doesn't means a "Mistake" is instantly fallacious. I belief this in itself is jumping conclusion and fallacious. I know that there will be people who may not agree with this but using real world scenario usage that informal logic to be more for, it seems to be the case.

So yes, I don't know if I misunderstand what Joseph said, but it sounds to me like he is saying: In Formal Logic where only the soundness and validity of a set matters, it is not fallacious to say if there is a wrong conclusion there is a fallacy. But in real world logic where there are more variables it may be fallacious. And after doing more search, I agree with that.

Conclusion: Not all wrong conclusion is inherently fallacious. Context matters. Although I suppose some who disagree with me may think this conclusion is fallacious...Maybe there is another way that better explain this but I strongly belief this is the answer.