Diego, as long as they live in a Californian place other than San Diego. However, one can affirm with certainty that "if someone does not live in California" (non-Q), then "this person does not live in San Diego" (non-P). This is the contrapositive of the first statement, and it must be true if and only if the original statement is true. Example 2 Here is another useful, obviously fallacious example. If an animal is a dog, then it has four legs. My cat has four legs. Therefore, my cat is a dog. Here, it is immediately intuitive that any number of other antecedents ("If an animal is a deer...", "If an animal is an elephant...", "If an animal is a moose...", etc.) can give rise to the consequent ("then it has four legs"), and that it is preposterous to suppose that having four legs must imply that the animal is a dog and nothing else. This is useful as a teaching example since most people can immediately recognize that the conclusion reached must be wrong (intuitively, a cat cannot be a dog), and that the method by which it was reached must therefore be fallacious. Example 3 Arguments of the same form can sometimes seem superficially convincing, as in the following example: If Brian had been thrown off the top of the Eiffel Tower, then he would be dead. Brian is dead. Therefore, Brian was thrown off the top of the Eiffel Tower. Being thrown off the top of the Eiffel Tower is not the only cause of death, since there exist numerous different causes of death. Example 4 In Catch-22, the chaplain is interrogated for supposedly being "Washington Irving"/"Irving Washington", who has been blocking out large portions of soldiers' letters home. The colonel has found such a letter, but with the Chaplain's name signed. "You can read, though, can't you?" the colonel persevered sarcastically. "The author signed his name." "That's my name there." "Then you wrote it. Q.E.D." P in this case is 'The chaplain signs his own name', and Q 'The chaplain's name is written'. The chaplain's name may be written, but he did not necessarily write it, as the colonel falsely concludes.Example 5 When teaching the scientific method, the following example is used to illustrate why, via the fallacy of affirming the consequent, no scientific theory is ever proven true but rather simply failed to be falsified.