Inductive vs Deductive Reasoning Help

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Updated on Sep 29, 2011

Introduction to Inductive vs Deductive Reasoning

"You should carefully study the Art of Reasoning, as it is what most people are very deficient in, and I know few things more disagreeable than to argue, or even converse with a man who has no idea of inductive and deductive philosophy."

—William J. Wills, explorer (1834–1861)

Lesson Summary

You hear arguments of all kinds throughout the day. In this lesson, you'll learn how to recognize the components of a deductive argument and how it differs from an inductive argument.

Consider the following conversation:

    "Junior, time to go to bed."
    "But why?"
    "Because I said so!"

Only a parent can get away with giving the answer "because I said so." But even parents sometimes have trouble using this approach to make a convincing argument. It's important to provide qualifiable reasons for asking someone to accept a claim or take a certain action. Providing qualifiable reasons is the best way to support your argument.

In the next three lessons, you're going to learn about deductive arguments: what they are, how they work, and how to recognize (and make) a good deductive argument—one that supports its assertions.

First, you need to know what deductive reasoning is. To help define it, the counterpart of deductive reasoning, which is inductive reasoning, will be introduced first.

Inductive Reasoning

When detectives arrive at the scene of a crime, the first thing they do is look for clues that can help them piece together what happened. A broken window, for example, might suggest how a burglar entered or exited. Likewise, the fact that an intruder didn't disturb anything but a painting that hid a safe might suggest that the burglar knew exactly where the safe was hidden. And this, in turn, suggests that the burglar knew the victim.

The process described above is called inductive reasoning. It consists of making observations and then drawing conclusions based on those observations.

Like a detective, you use inductive reasoning all the time in your daily life. You might notice, for example, that every time you eat a hot dog with chili and onions, you get a stomachache. Using inductive reasoning, you could logically conclude that the chili dogs cause indigestion, and that you should probably stop eating them. Similarly, you might notice that your cat tries to scratch you every time you rub her stomach. You could logically conclude that she does not like her stomach rubbed. In both examples, what you're doing is moving from the specific—a particular observation—to the general—a larger conclusion. Inductive reasoning starts from observation and evidence and leads to a conclusion.

Using inductive reasoning generally involves the following questions:

  1. What have you observed? What evidence is available?
  2. What can you conclude from that evidence?
  3. Is that conclusion logical?

We'll come back to these questions in a later lesson. For now, you know enough about inductive reasoning to see how deductive reasoning differs from it.


The word syllogism means "logical appeal" and is considered a type of logical argument and an important element in formal conclusions and premises. Truth tables, on the other hand, are mathematical tables that examine numerical formulas—and are way too complicated to cover here!

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