chapter 8Applied Logic

Once the people begin to reason, all is lost.

—Voltaire (1694-1778)

When we reason, we usually do it in a particular domain of discourse. For example, we might reason about computer science, politics, mathematics, physics, automobiles, or cooking. But these domains are usually too large to do much reasoning. So we normally narrow our scope of thought and reason in domains such as imperative programming languages, international trade, plane geometry, optics, suspension systems, or pasta recipes.

No matter what the domain of discussion, we usually try to correctly apply inferences while we are reasoning. Since each of us has our own personal reasoning system, we sometimes find it difficult to understand one another. In ...

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