Determining Types of Reasoning

Photo of Auguste Rodin's sculpture called The Thinker

Source: “The Thinker,” Ed Mendez, Flickr

Think of times you’ve made an important decision, such as whether to take a part-time job, buy a car, or select a gift for someone special. You might have started with your claim (thesis): “I must buy a car because _____ (list of all the reasons).” You used deduction. Or you might have reversed the order: “(List of all the reasons); therefore, I must buy a car.” Here, you used induction. You planned your argument based upon what you knew about your audience. All writers of valid, acceptable arguments develop them based upon the audience they want to influence.

Review the following examples. Find the claim (thesis) in each sentence and click on it. If you choose correctly, the claim will highlight.

  1. All my teachers drive old cars, bring their lunches from home, and wear out-of-date clothes. They must not make much money.
  2. The way we eat has changed. Farmers’ markets have sprung up all over town; people have planted vegetable gardens and are buying healthy-eating cookbooks and magazines, and restaurants now display the caloric and fat content of their meals.
  3. Sam has taken swim lessons for years and swims very well. He will definitely make the high school swim team.
  4. Holly must be allergic to poison ivy. She breaks out in an itchy rash every time she goes hiking in the woods.
  5. We saw a group of scruffy-looking teenagers walking along carrying cans of spray paint. They probably defaced the neighborhood with graffiti.
  6. My mother appreciates receiving books as presents, and she especially enjoys Barbara Kingsolver’s novels. She will like the copy of Kingsolver’s novel The Lacuna that I bought for her birthday next week.
  7. People will have many wrecks today around Texas. It’s raining, and Texans have a notoriously difficult time driving in the rain.
  8. Jay Gatsby deserves no sympathy as a “victim” of the American Dream. He acquired his wealth through criminal activities, such as bootlegging and gambling.

Read each sentence again and decide if it is an example of deductive or inductive reasoning.