And so is this: People in Kentucky support a border fence. People in New York do not support a border fence. Therefore, people in New York do not support people in Kentucky. Indeed, there is no logical principle that states: For some x, P(x). For some x, Q(x). Therefore, for some x, P(x) and Q(x). An easy way to show the above inference as invalid is by using Venn diagrams. In logical parlance, the inference is invalid, since under at least one interpretation of the predicates it is not validity preserving. People often have difficulty applying the rules of logic. For example, a person may say the following syllogism is valid, when in fact it is not: All birds have beaks. That creature has a beak. Therefore, that creature is a bird. "That creature" may well be a bird, but the conclusion does not follow from the premises. Certain other animals also have beaks, for example: an octopus and a squid both have beaks, some turtles and cetaceans have beaks. Errors of this type occur because people reverse a premise. In this case, "All birds have beaks" is converted to "All beaked animals are birds." The reversed premise is plausible because few people are aware of any instances of beaked creatures besides birds—but this premise is not the one that was given. In this way, the deductive fallacy is formed by points that may individually appear logical, but when placed together are shown to be incorrect. Non sequitur in everyday speech In everyday speech, a non sequitur is a statement in which the final part is totally unrelated to the first part, for example: See also References Notes Bibliography Aristotle, On Sophistical Refutations, De Sophistici Elenchi. William of Ockham, Summa of Logic (ca. 1323) Part III.4. John Buridan, Summulae de dialectica Book VII. Francis Bacon, the doctrine of the idols in Novum Organum Scientiarum, Aphorisms concerning The Interpretation of Nature and the Kingdom of Man, XXIIIff . The Art of Controversy | Die Kunst, Recht zu behalten – The Art Of Controversy (bilingual), by Arthur Schopenhauer John Stuart Mill, A System of Logic – Raciocinative and Inductive. Book 5, Chapter 7, Fallacies of Confusion. C. L. Hamblin, Fallacies. Methuen London, 1970. Fearnside, W. Ward and William B. Holther, Fallacy: The Counterfeit of Argument, 1959. Vincent F. Hendricks, Thought 2 Talk: A Crash Course in Reflection and Expression, New York: Automatic