Modo Hoc

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© 2011-2019 by Zack Smith. All rights reserved.

Modo Hoc

In this fallacy, which is related to the Fallacy of Composition, the internal arrangement of constituent parts of a thing is ignored or discounted as a cause of its nature.

  • Object A has parts B and C arranged in some way.
  • Object A has Trait X.
  • Therefore A always has Trait X -- regardless of how B and C are arranged. ]]


A car's engine has parts that are metallic and capable of generating heat and motion. You take the engine apart but now its parts are not capable of generating heat and motion. The fallacy is in claiming that they do.


Typically the arguer has no comprehension of the inner workings of Object A. Demand that they explain their understanding.

The arguer often has no understanding of why Object A has characteristic X. Demand that they explain the origin of that trait.

You can elicit speculation with them. For instance, so if we connect this hose to that engine block, it will still work, right?