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This resource covers using logic within writing—logical vocabulary, logical fallacies, and other types of logos-based reasoning. Logical VocabularyBefore using logic to reach conclusions, it is helpful to know some important vocabulary related to logic. Premise: Proposition used as evidence in an argument. Reaching Logical ConclusionsReaching logical conclusions depends on the proper analysis of premises. The goal of a syllogism is to arrange premises so that only one true conclusion is possible. Example A: Premise 1: Non-renewable resources do not exist in infinite supply. From these two premises, only one logical conclusion is available: Conclusion: Coal does not exist in infinite supply. Example B: Premise 1: All monkeys are primates. Example C: Premise 1: All squares are rectangles. Syllogistic FallaciesThe syllogism is a helpful tool for organizing persuasive logical arguments. However, if used carelessly, syllogisms can instill a false sense of confidence in unfounded conclusions. The examples in this section demonstrate how this can happen. Example D: Premise 1: Some quadrilaterals are squares. This syllogism is false because not enough information is provided to allow a verifiable conclusion. Figure 1 could just as likely be a rectangle, which is also a quadrilateral. Example E: Premise 1: People with red hair
are not good at checkers. Within the syllogism, the conclusion is logically valid. However, the syllogism itself is only true if an audience accepts Premise 1, which is very unlikely. This is an example of how logical statements can appear accurate while being completely false. Example F: Premise 1: All birds lay eggs. It is true that all birds lay eggs. However, it is also true that some animals that are not birds lay eggs. These include fish, amphibians, reptiles, and a small number of mammals (like the platypus and echidna). To put this another way: laying eggs is not a defining characteristic of birds. Thus, the syllogism, which assumes that because all birds lay eggs, only birds lay eggs, produces an incorrect conclusion. A better syllogism might look like this: Premise 1: All mammals have fur. Fur is indeed one of the defining characteristics of mammals—in other words, there are not non-mammal animals who also have fur. Thus, the conclusion here is more firmly-supported. In sum, though logic is a very powerful argumentative tool and is far preferable to a disorganized argument, logic does have limitations. It must also be effectively developed from a syllogism into a written piece. Is the process of using premises and logical principles?Deductive Reasoning is the process of using premises (accepted facts) and logical principles to arrive at a specific conclusion.
What is the process of thinking by which an individual forms a conclusion from premises?Inductive reasoning takes you from the specific to the general, while in deductive reasoning, you make inferences by going from general premises to specific conclusions.
What is the process of using logic to draw conclusions?Reasoning is the process of using existing knowledge to draw conclusions, make predictions, or construct explanations.
What is the word for the reasoning that connects premises and a conclusion?Deductive reasoning relies on making logical premises and basing a conclusion around those premises. It does not rely on making inferences, then assuming those inferences to be true.
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