Proof by example

Proof by example is a logical fallacy whereby an example is claimed as evidence for a universal claim. The structure looks like this:


 * 1. I know that x has property P.
 * 2. x belongs to group G.
 * C. Therefore, all other elements of group G have property P.

Arguments using examples are valid only when leading to existential conclusions, not general ones.


 * 1. I know that x has property P.
 * 2. x belongs to group G.
 * C. Therefore, some member of group G has property P.

Moreover, no number of examples can establish the universal claim unless it is also predicated that all members of the group have been accounted for.


 * 1. x, y and z have property P.
 * 2. x, y, and z belong to group G.
 * 3. x, y, and z account for all the members of group G.
 * C. All members of group G have property P.

The conclusion of this statement is predicated on the third premise just as strongly as the other two premises. Without it, the argument constitutes a fallacy of proof by example.

There are many uses of proof by examples in apologetics. Some are with respect to design arguments, and others are involved in claims made about religious institutions, and the causal relationship that those institutions have on individuals and societies. The causal element can make these arguments slightly more complicated; however, in many cases, the operative fallacy is still proof by example.