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"Example Statement: All Secret Service Special Agents are U.S. government employees. Invalid conclusion: All government employees are Secret Service Special Ag
by OscarCunningham 12y ago
"Example Statement: All Secret Service Special Agents are U.S. government employees.
Invalid conclusion: All government employees are Secret Service Special Agents.
Valid conclusion: Some U.S. government employees are Secret Service Special Agents."
- cperciva 12y agoThe funny thing is, this example isn't even true. Knowing that all Secret Service Special Agents are US government employees does not allow you to logically conclude that some US government employees are Secret Service Special Agents -- you also need to know that at least one Secret Service Special Agent exists! For example, it is true that all humans living on Mars are US government employees -- but not at all true that some US government employees are living on Mars.
- CamperBob2 12y agoIf you take the question abstractly enough, with zero a priori knowledge, then the example becomes valid again. There may not even be any US government employees at all, anywhere.
- cperciva 12y agoIf there are no US government employees, then the statement "some US employees have property X" is false for all values of X.
- CamperBob2 12y agoEver taken an IQ test? One reason for phrasing the questions in terms like "All gribs are freebles, and some freebles are blorts" is to avoid that kind of problem. Obviously, the intent with all test questions of this nature is for you to treat all nouns as abstractions.
- cperciva 12y agoAll humans living on Mars were born on Venus. <-- True Some humans living on Mars were born on Venus. <-- False
- CamperBob2 12y agoThat isn't how these questions work.
- cperciva 12y agoIt is how logic works.
- CamperBob2 12y agoI'm sure the authors of the test are busy taking notes.
- freakonom 12y agos/Secret Service Special Agents/American hijackers/ s/U.S. government employees/Americans/ We therefore conclude that "Some Americans are American hijackers." The logic's airtight; it comes from a secret service test designed to evaluate logic ability. Suddenly the TSA makes sense.