Evaluating Arguments, Part 5: Fallacies

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I have discussed fallacies before, and in that post I provided some wonderful sources that pertain exclusively to logical fallacies. It would be entirely remiss of me, though, to ignore fallacies in relation to evaluating arguments. This post will, like all posts of this series, give some specific examples of fallacies in action. So, without further ado, let’s get into yet another way to assess/evaluate an argument!

The argument (or premise) commits any number of informal fallacies, such as:

  • Straw man
  • Guilt by association
  • False equivalence
  • False dichotomy
  • Special pleading
  • Slippery slope
  • Composition
  • Genetic fallacy
  • Personal incredulity

Let’s take, for example, the fallacy of division. The following considerations are from ThoughtCo (with some emendations).

“The fallacy of division is similar to the fallacy of composition but in reverse. This fallacy involves someone taking an attribute of a whole or a class and assuming that it must also necessarily be true of each part or member.

The form of this fallacy is as follows:

A has property X. Therefore, all parts (or members) of A have this property X.


Specific examples:

The United States is the richest country in the world. Therefore, everyone in the United States must be rich and live well.

The American judicial system is a fair system. Therefore, the defendant got a fair trial and was not executed unfairly.

Just as with the fallacy of composition, it is possible to create similar arguments which are valid. Here are some examples:

All dogs are from the canidae family. Therefore, my Golden Retriever is from the canidae family.

All men are mortal. Therefore, Socrates is mortal.


Why are these last two examples valid arguments?

The difference is between distributive and collective attributes.

Attributes which are shared by all members of a class are called distributive because the attribute is distributed among all members by virtue of being a member. Attributes which are created only by bringing together the right parts in the right way are called collective. This is because it is an attribute of a collection, rather than of the individuals.

These examples will illustrate the difference:

Stars are large.

Stars are numerous.

Each statement modifies the word stars with an attribute. In the first, the attribute large is distributive. It is a quality held by each star individually, regardless of whether it is in a group or not. In the second sentence, the attribute numerous is collective. It is an attribute of the entire group of stars and only exists because of the collection. No individual star can have the attribute “numerous.”

This demonstrates a primary reason why so many arguments like this are fallacious. When we bring things together, they can often result in a whole which has new properties unavailable to the parts individually. This is what is often meant by the phrase “the whole is more than the sum of the parts.”

Just because atoms put together in a certain way constitute a living dog does not mean that all atoms are living — or that the atoms are themselves dogs.

Here is a slightly more complicated example of the fallacy of division:

Unless each cell in your brain is capable of consciousness and thinking, then the consciousness and thinking in your brain cannot be explained by matter alone.

It doesn’t look like the other examples, but it is still the fallacy of division — it’s just been hidden. We can see it better if we more clearly state the hidden premise:

If your (material) brain is capable of consciousness, then each cell of your brain must be capable of consciousness. But we know that each cell of your brain does not possess consciousness. Therefore, your (material) brain itself cannot be the source of your consciousness.

This argument presumes that if something is true of the whole, then it must be true of the parts. Because it is not true that each cell in your brain is individually capable of consciousness, the argument concludes that there must be something more involved — something other than material cells.

Yet, once we realize that the argument contains a fallacy, we no longer have a reason to hold that consciousness is (caused by) something apart from the physical brain.

It would be like using this argument:

Unless each part of a car is capable of self-propulsion, then self-propulsion in a car cannot be explained by the material car-parts alone.

No intelligent person would ever think to use or accept this argument, but it’s structurally similar to the consciousness example. One could maintain that consciousness results from the concerted effort of the whole brain and is thus not equivalent to the sum of its parts” (ThoughtCo).

Once again, I am not presently taking any stances on the nature of consciousness. This example is simply illustrative of the fallacy in question.

Here is one final example:

“Evolutionarily-instilled dispositions explain why religion exists. It is merely adaptively advantageous and serves for purposes of social cohesion. Therefore, since it is merely adaptive and not truth-seeking, one ought to reject it.”

This is, though, a genetic fallacy. Merely from the fact that religious belief originated from evolution or adaptive behavior, it doesn’t follow that religious belief is thereby false. The origin of something does not thereby make it true or false — it’s truth or falsity is a function of whether or not it corresponds to the way the world is in reality.

What’s more, this type of argument is self-defeating. Consider that (on this account) all our cognitive faculties originated by means of evolution. Hence, if X originating by means of evolution is sufficient for showing X to be false or unreliable, it follows that none of our cognitive faculties are reliable. But, of course, this is self-defeating, since in order to justify this very claim one must presuppose the reliability of his or her cognitive faculties.

Author: Joe

Email: NaturalisticallyInclined@gmail.org

Source: https://www.thoughtco.com/what-is-the-fallacy-of-division-250352

1 thought on “Evaluating Arguments, Part 5: Fallacies

  1. Pingback: An Index of Blog Series! | Majesty of Reason

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