CRITICAL THINKING – Fallacies: Fallacy of Composition
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CRITICAL THINKING – Fallacies: Fallacy of Composition

October 15, 2019


(Intro music) Hello, I’m Paul Henne and I’m a philosophy graduate student at Duke University. And in this video I’m gonna talk to you about a particular informal fallacy called the fallacy of composition. In doing this, I’m also going to tell you why we sometimes can’t conclude[br]that there are colorless cats. But I’ll get to that idea in a second. To recall, an informal fallacy is an argument whose premises[br]do not support its conclusion. Generally, a fallacy is[br]a defect in reasoning. And there are two types of[br]fallacies: formal and informal. A formal fallacy is an[br]argument with an error in the form of the argument and an informal fallacy contains an error in the content of the argument. But you can learn more[br]about this distinction in the video about informal[br]and formal fallacies, which should be out soon. For this video, we’re going to focus on a particular informal fallacy. So, the fallacy of composition[br]is an error in reasoning that arises in the content of an argument. People commit this error[br]when they draw conclusions about the whole from truths[br]about its constituent parts, without having a[br]justification for doing so. That is, they think without justification that what is true of[br]the parts of something must also be true of the whole those parts compose. Sounds problematic, right? But let’s represent this[br]logical error more formally. The reasoning would be[br]something like this. Premise one: The parts of whole A have qualities X, Y, and Z. Conclusion one: Therefore, whole A must have qualities X, Y, and Z. The argument seems[br]attractive, but the style of argument is like saying that because the states[br]have some set of qualities, then the entire nation[br]must have those qualities. You may now be able to see what’s wrong with this line of reasoning. Without sufficient justification, we cannot infer that the[br]whole has the same qualities as its parts simply because[br]the parts have that quality. It may be the case that the[br]whole lacks the qualities that the parts have. It’s like saying that because[br]Arizona has an arid climate, the entire nation has an arid climate too. Let’s look at a few more examples. It’s true that the number three and the number seven are both odd numbers. We might say that three and seven have the characteristic of being odd. Each is also a part of the number ten. Three plus seven equals ten. But we cannot say that the number ten is odd simply because its[br]parts, three and seven, have that quality. If we did, we would commit[br]the fallacy of composition. Let’s try another example. Suppose your friend made this argument. Premise one: Atoms are colorless. Premise two: Cats, we know, are[br]composed of a bunch of atoms. Conclusion: Therefore,[br]cats are colorless too. Well, we know that cats[br]are not in fact colorless but we can also see where[br]this person made her error. Without justification,[br]she assumed that the whole has the same qualities as its parts. So, even though the premises[br]of her argument are true she committed the fallacy of composition. So, we don’t have to worry[br]about any colorless cats. So, we just learned about[br]the fallacy of composition, or the error in reasoning that comes about when one infers that the[br]whole has the same qualities as its constituent parts. It is important, however, to note that this style of reasoning doesn’t always lead to false conclusions. You friend, for instance,[br]might argue the following. Premise one: Every part of[br]my cat is composed of matter. Conclusion: Therefore, my[br]cat is composed of matter. And her argument leads[br]to a true conclusion. The fallacy only arises when we don’t have a good reason to infer that the whole has the same qualities as its parts. So, remember to stay[br]vigilant of this fallacy and not to worry about any colorless cats. Subtitles by the Amara.org community

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  1. This seems to put a major dent in any logical argument for the existence of the universe requiring a cause. How can we talk of causality of the universe when everything we know of causality takes place within the universe?

  2. Funnily enough, for some reason this vid made me think of the argument for dualism, we cannot find consciousness in any of the parts, therefore it must be elsewhere. I never thought of it as a fallacy of composition before! Good video. 🙂

  3. Those who side with dualism have a want, not a belief. Beliefs require evidence to support them as being valid.

  4. I'm not sure why you think siding with dualism is a want and not a belief. Surely having a belief in dualism is a belief. To say that it's just a "want" is empty rhetoric. But that's besides the point. There are plenty of logical arguments for dualism. All of them, in my opinion, are inadequate, but they are logical. And on another note, validity in logic isn't based around evidence. It's based around the logical structure of an argument.

  5. based around? That does not compute Will Robinson. Logical structure cannot be used as evidence is what you are saying? …………interesting

  6. logical structure can be used as evidence. I didn't say it could not. I said validity in logic isn't based around evidence. There is a difference. You can have invalid logical forms based around evidence, and the evidence wouldn't be sufficient to make an invalid argument a valid one. But that's rather tangential to your original comment. The point is there are logical arguments for dualism.

  7. Really? Because the Philosophy and Psychology I studied says dualism is a complete failure, and contradicts current scientific knowledge to a fault.
    You should try watching the lectures of: Shelly Kagan (Philosophy), Paul Bloom (Psychology) on the YT channel "YaleCourses".
    And if that doesn't do it for you, they uploaded "critical" New and Old Testament lectures from Yale University.
    The magic trick is exposed, the cat is out of the bag, and the game is over.

  8. I'm very well aware of lectures. I teach philosophy. I noted that dualism is an inadequate view of the mind. It has many problems. It does in fact fly in the face of our current scientific understanding. But that doesn't mean one cannot make a logical argument for it.
    If dogs are felines then apes are made of cheese.
    Apes are not made of cheese.
    Therefore dogs are not felines.

    Completely logical argument with a true conclusion. It is also in fact a valid argument. Nonsense. But logical.

  9. I'm sorry to butt in, but you can have a valid argument containing false premises. I think that you are concerned with the soundness of the argument – a different (and interesting) requirement all together.

    Also, there is no need to insult anyone. This conversation seems productive; you are both sharing resources and arguments. I think it's totally rad. Thanks for the comments!

  10. "If dogs are felines then apes are made of cheese." <—This premise is false, full stop
    How does Apes not being made of cheese correlate (You said "Therefore") to dogs not being felines. Nonsense as you say, but I can't get to the logical equals illogical part, it has thrown me.

  11. Protectionism is good for General Motors. General Motors is part of the American economy. Therefore protectionism is good for the American economy. QED?

  12. In this case, you can only conclude that protectionism is good for a part of the American economy, right? It might be the case that protectionism is terrible for AT&T or Google.

  13. It's even worse than that. Protectionism in cars is good for GM because that means it can act as a monopolist, producing less cars and selling them at a higher price. It makes GM better off at the expense of American consumers, so the statement is not true.

  14. plenty of logical arguments have false premises. Even valid arguments can have false premises and false conclusions. Look up the definition of validity in logic, and you may learn something.

  15. agreed. Soundness is very different from validity and it is often overlooked and misunderstood. No hard feelings to anyone. Just trying to clarify the issues 🙂

  16. One of the most interesting questions ever, in my opinion. I heard the same question asked in Bertrand Russell's "Why I Am Not A Christian" and have wondered about it ever since.

  17. If this guy is a lecturer and the students are failing then the world is surely coming to an end……This guy forces information into your head…He's awesome #NoHomo  

  18. I have hair, my mum has hair, my dad has hair, my sister has hair, but that doesn't mean that the Hafezparast family have hair XD

  19. great job on all your stuff! didn't really like the atoms are colorless example- atoms could be a bunch of atoms bonded together, no? it threw me off is all. cheers

  20. couldn't this be an example of an equivocation fallacy, where atoms of premise 1 are non bonded and in a gas form are truly colorless, but the atoms in premise 2 are bonded and thus have color? aren't we talking about two different "atoms". atoms are colorless depending upon how you define them, and the definition changes from P1 to P2. help me out here, thanks.

  21. The cat has a mind too; and we don´t know it that is emerging from matter. Probably it´s not:)

  22. This is a great set of videos. Top notch. The comparison of Arizona's climate to the climate of the nation is great.

  23. If I stand up in a theater, I will be able to see better. Therefore, if everyone stands up, everyone will see better, right?

  24. Thanks for your break down of this fallacy. We're covering it in class, but it isn't in our textbook. Now I've got an understanding of this informal fallacy when I head to class.

  25. Atoms also aren't colorless. There's a whole field of chemistry devoted to splitting substances and shining light on them to observe their behavior and color and determine what they are based off that. So that argument has 2 false premises.

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