"Planets are big. Therefore, the atoms from which they are made are big". This…

CONCEPT: A fallacy of division occurs when an argument assumes that what is true of a whole must also be true of its individual parts.

The error is a distributive mistake: a collective property need not be inherited by each component of the collective object.

APPLICATION: The statement says that planets are big and then transfers that size-property to the atoms that compose planets.

That transfer is invalid because the size of an assembled object and the size of its atomic constituents are properties at different levels.

CONTRAST:

• Fallacy of Ambiguity concerns unclear wording or multiple possible interpretations, not a whole-to-part attribution.

• Fallacy of Equivocation requires a key word to shift meaning during the argument; the word big is not doing that here.

• Ad populum relies on popularity or majority belief; no appeal to public opinion appears in the statement.

Result: the inference commits the Fallacy of Division.