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Fallacy of Composition

(also known as: composition fallacy, exception fallacy, faulty induction)

Description: Inferring that something is true of the whole from the fact that it is true of some part of the whole.  This is the opposite of the fallacy of division.

Logical Form:

A is part of B.

A has property X.

Therefore, B has property X.

Example #1:

Each brick in that building weighs less than a pound.  Therefore, the building weighs less than a pound.

Example #2:

Hydrogen is not wet.  Oxygen is not wet.  Therefore, water (H2O) is not wet.

Example #3:

Your brain is made of molecules.  Molecules do not have consciousness.  Therefore, your brain cannot be the source of consciousness.

Explanation: I included three examples that demonstrate this fallacy from the very obvious to the less obvious, but equally as flawed.  In the first example, it is obvious because weight is cumulative.  In the second example, we know that water is wet, but we only experience the property of wetness when the molecules are combined and in large scale.  This introduces the concept of emergent properties, which when ignored, tends to promote magical thinking.  The final example is a common argument made for a supernatural explanation for consciousness.  On the surface, it is difficult to imagine a collection of molecules resulting in something like consciousness because we are focusing on the properties of the parts (molecules) and not the whole system, which incorporates emergence, motion, the use of energy, temperature (vibration), order, and other relational properties.

Exception: If the whole is very close to the similarity of the parts, then more assumptions can be made from the parts to the whole.  For example, if we open a small bag of potato chips and discover that the first one is delicious, it is not fallacious to conclude that the whole snack (all the chips, minus the bag) will be just as delicious, but we cannot say the same for one of those giant family size bags because most of us would be hurling after about 10 minutes of our chip-eating frenzy.

References:

Goodman, M. F. (1993). First Logic. University Press of America.



Registered User Comments

Jacob
Monday, September 10, 2018 - 09:13:32 PM
Sally Struthers says, "Your donation can help feed Africa."

I know what she means. If many people donate to her cause then many people in Africa can be fed. It is a figure of speech called Synecdoche. "Africa" is used to represent "people in Africa".

Is this also a fallacy of composition?

A(African children) is part of B(Africa).
A(African children) has property X(ability to be fed).
Therefore, B(Africa) has property X(ability to be fed).

You can literally feed an African child but you can't literally feed Africa, although you can metaphorically.

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Bo Bennett, PhD
Tuesday, September 11, 2018 - 08:51:58 AM
I think only if one takes this literally, but clearly (as you suggest) this is not meant to be taken literally.

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Jason Mathias
Wednesday, February 14, 2018 - 09:58:21 PM
Is this a composition fallacy? Life is made of non living atoms, so life is an illusion because there is no clear separation between living and non living.

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Raven
Wednesday, February 21, 2018 - 01:47:47 PM
@Bo Bennett, PhD:
... it is more of an unsupported claim than a fallacy (as I think more about it). The claim appears to be that because there is no clear separation between two ends of the continuum, then one end of the spectrum is an illusion.
That would be a fallacy, wouldn't it? A fallacy of vagueness, akin to denying the existence of the Atlantic Ocean (or your neighbor's land-rights, or the "public interest") because "its boundaries are vague."

Hmmm, you don't seem to cover that one. It's not the same as fallacy of equivocation (switching between meanings of ambiguous words), which is what pops up in a search on "vagueness" here. Maybe add a new entry?

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Bo Bennett, PhD
Wednesday, February 21, 2018 - 04:58:29 PM
@Raven: I’m not convinced it is a problem with reasoning or common enough to be named. The difference between what someone calls an illusion, claims does not exist, or is on a continuum can be an argument of semantics. I would like to hear the philosophical argument behind the claim. Again, I suspect more often than not that the reasoning is sound; it’s just a game of semantics being played.

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Jason Mathias
Wednesday, February 21, 2018 - 06:46:19 PM
@Bo Bennett, PhD: //"I would like to hear the philosophical argument behind the claim"// Does this mean you would like to see the argument in a syllogistic form?

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Jason Mathias
Wednesday, February 21, 2018 - 07:13:28 PM
@Bo Bennett, PhD: If I had to put it in a syllogistic form it would probably go something like this:
1- Life is comprised of physical material (i.e carbon, hydrogen, oxygen, phosphorus, sulfur, and nitrogen.)
2- Only non living material exists.
3- Life is made of material.
4- Therefor living material doesn't exist.
5- Therefor life doesn't exist.

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Bo Bennett, PhD
Wednesday, February 21, 2018 - 09:41:39 PM
@Jason Mathias : This (as you have written it) is more in line with the fallacy of composition. Most materialists would agree with premise #1. Premise #2 gets messy because "material" is not well-defined, and could mean living tissue or organisms. If you stick with "atoms" you can avoid this ambiguity. Also move some redundancy. Perhaps:

1. Life is comprised ONLY of atoms.
2. atoms are not living
3. Therefore, life is not living (and thus, an illusion)

The flaw in this argument is exactly this fallacy... the assertion that what is true of the parts must be true of the whole.

1. Supermodels in skimpy swimsuits are made only of atoms
2. atoms don't give me an erection
3. Therefore, supermodels in skimpy swimsuits don't give me an erection

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Jason Mathias
Wednesday, February 21, 2018 - 10:01:44 PM
@Bo Bennett, PhD: Thats pretty funny lol.

"1. Supermodels in skimpy swimsuits are made only of atoms
2. atoms don't give me an erection
3. Therefore, supermodels in skimpy swimsuits don't give me an erection"

If the supermodels that give you an erection are made of atoms, then doesn't that mean that atoms give you an erection?

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Bo Bennett, PhD
Thursday, February 22, 2018 - 07:14:05 AM
@Jason Mathias: That would be ambiguous at best and poor communication. If we agreed that responding this way was reasonable, then virtually every answer to every question answered by a noun would be “atoms” and no new information would be shared. This is the problem with ambiguity.

What’s your favorite ice cream flavor? Atoms.
What did you buy at the mall today? Atoms.
How did you get to work today? I took atoms.

Being correct on an absract level can still mean your wrong on a practical, and more important, useful level.

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Raven
Saturday, February 24, 2018 - 07:51:28 AM
@Bo Bennett, PhD:
I’m not convinced it ["fallacy of vagueness"] is a problem with reasoning or common enough to be named.
See for instance fallacyfiles.org:Vagueness:
"Taxonomy: Logical Fallacy > Informal Fallacy > Vagueness
"Subfallacy: The Fallacy of the Heap [Forms: (1) A differs from Z by a continuum of insignificant changes, and there is no non-arbitrary place at which a sharp line between the two can be drawn. Therefore, there is really no difference between A and Z. (2) A differs from Z by a continuum of insignificant changes with no non-arbitrary line between the two. Therefore, A doesn't exist. Example: A single grain of sand does not make a heap of sand. Also, a single grain of sand won't turn a non-heap into a heap. Therefore, there are no heaps of sand. ... Similarly, the lack of a bright line between contrary concepts does not mean that one of the concepts is a myth―that is, there is nothing to which it refers. For example, some people have argued that there is no such thing as life, since the line between animate and inanimate thing is fuzzy. However, we can all easily identify many living things and nonliving things, and the fact that there are some things which fall into a gray area―viruses, for instance―does not mean that the concept of life is without reference.]
"Vagueness should be distinguished from ambiguity: an ambiguous term has more than one meaning, whereas vagueness is characteristic of a single meaning that has borderline cases. However, it is not unusual for a term to be both ambiguous and vague; in fact, this is the usual case. "

I would have thought that this is not only a common, and clearly identified, problem with reasoning, but exactly the one at issue.

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Bo Bennett, PhD
Saturday, February 24, 2018 - 09:04:23 AM
@Raven: I have this listed as well here: https://www.logicallyfallacious.com/tools/lp/Bo/LogicalFallacies/58/Argument-of-the-Beard. Perhaps where I am seeing the difference is in the claim that no useful distinction can be made vs. one of the ends being illusory. So back to the example:

Life is made of non living atoms, so life is an illusion because there is no clear separation between living and non living.

Would be different from: Life is made of non living atoms, so there is no difference between living and non living. This is far more common than the illusory claim, which I see as very different in terms of what is meant.

Again, this is just my take on it. There is quite a bit of subjectivity involved with informal fallacies.

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Raven
Friday, March 02, 2018 - 12:38:33 AM
@Bo Bennett, PhD: Your own article uses both phrases, (in the 'Description') "that no useful distinction can be made between two extremes", and (in the 'Logical Form') "Therefore, there is no difference between X and Y."

Yes, these CAN mean different things, in the sense that someone can make "a [false] distinction without a difference" — in effect drawing an entirely arbitrary borderline on a mental chart that doesn't reflect anything in reality — but a [non-false] distinction is a difference (that someone has pointed out).

As with my earlier example, if the borders of the Atlantic Ocean are vague, does it not exist? Perhaps it is all part of one universal Pan-Oceanic water, and should not be separately named....

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