Understanding Logic

Logic is the careful thought that guides an argument. It comes from the Latin root logos, which means “word.” In its most basic form, then, logic refers to the way that words connect to make meaning. Here are three basic ways that words carry meaning:
  • Definitions: Every word has a definition, which is the starting point for making meaning. Often, a word will have multiple definitions, and the true meaning must be derived from the way it is used.

manipulate: (1) to change with the hands, (2) to handle skillfully, (3) to modify in an unfair or deceitful way

  • Syntax: The syntax is the way that words are arranged or used. A word’s meaning becomes apparent by whether it is used as a subject, a verb, an object, or a modifier. In the phrase “manipulate feelings,” meaning is determined by the words’ use.

manipulate feelings: to unfairly or deceitfully modify a person’s emotions

  • Semantics: Semantics refers to the larger-scale meaning of language. A complete sentence offers you the basic semantic structure, or claim. Paragraphs, essays, and books extend the semantic structures to larger and larger forms.

Negative political ads manipulate voters’ feelings so that they vote against rather than for a candidate.

Your Turn Open one of your textbooks and point randomly to a word. Define the word. Then consider the words next to the one you chose. Does the syntax change your definition? Finally, consider the whole sentence. What does it mean semantically? Write the sentence in your own words.


Separating Fact from Opinion

At a very basic level, you need to understand the difference between a fact and an opinion. Often your argument will start with an opinion, but all arguments must contain plenty of factual evidence.

  • Facts are statements that can be objectively proven based on evidence.

John F. Kennedy was the 35th president of the United States.

  • Opinions are personally held beliefs that cannot be objectively proven.

John F. Kennedy was the most important president of the 20th century.

Your Turn Write a factual statement about the current president of the United States. Write an opinion statement about the current president. Compare your statements with a classmate’s and discuss what makes each a fact or an opinion.