Composition

Form:

All of the parts of the object O have the property P.
Therefore, O has the property P.
(Where the property P is one which does not distribute from parts to a whole.)

Example:

Should we not assume that just as the eye, hand, the foot, and in general each part of the body clearly has its own proper function, so man too has some function over and above the function of his parts?

Source: Aristotle, Nicomachean Ethics, Martin Ostwald, translator (Bobbs-Merrill, 1962), p. 16.

Analysis

Counter-Example:

The human body is made up of cells, which are invisible.
Therefore, the body is invisible.

Exposition:

Some properties are such that, if every part of a whole has the property, then the whole will too—for example, visibility. However, not all properties are like this—for instance, invisibility. All visible objects are made up of atoms, which are too small to see. Let's call a property which distributes from all of the parts to the whole an "expansive" property, using Nelson Goodman's term. If P is an expansive property, then the argument form above is validating, by definition of what such a property is. However, if P is not expansive, then the argument form is non-validating, and any argument of that form commits the fallacy of Composition.

Sibling Fallacy: Division

Sources:

• S. Morris Engel, Analyzing Informal Fallacies (Prentice-Hall, 1980), pp. 25-26.
• Thomas Mautner (Editor), A Dictionary of Philosophy (Blackwell, 1996).

Analysis of the Example:

The function of an organ is definable in terms of what the organ does to help the whole organism to live, however, one cannot define a function for the organism as a whole in this way. For this reason, "function" is not expansive. If it were true that human beings as a whole have a function, this would be a very different notion of function than that of the function of a human organ. So, even in this case, Aristotle's argument would commit a fallacy, though a different one, namely, Equivocation.