Breaking news from a recent poll: 100% of the four people surveyed have been bitten by a snake at some point in their lives, and all four have experienced mild ringing in the ears at some point since. This astounding news suggests that 100% of all people have experienced this phenomenon, and that snake bites can result in superpowers. Conclusion? Everyone has superpowers.
Fig. 1 - Shocked at the inductive leap in logic.
These outrageous conclusions are the result of an enormous leap of induction. Most examples of induction aren't this absurd. In fact, logical induction is not only a part of everyday life, but also a powerful tool in rhetoric and persuasive writing.
What is the Definition of Induction as a Rhetorical Mode?
People use induction every day to process the world around them and communicate with others.
Induction (also called inductive reasoning) is the logical method of drawing general conclusions based on specific observations.
These are some of the forms that induction can take:
- Predictions: using observations about the past or present to predict the future. The power went out during the snowstorm last year. If there's a snowstorm this year, the power will go out.
- Causal inference: noticing a correlation between two events and concluding that one causes the other.Every time I eat a banana, my ears get itchy. I must have an allergic reaction to bananas.
- Generalization: noticing a pattern in some contexts and concluding that the pattern also applies in other contexts.I took four potatoes out of this bag and they were all rotten. That probably means that all of the potatoes in this bag are rotten.
It's important to note that while induction is a powerful form of logic and a big part of people's understanding of the world, induction can't actually prove its conclusions. You can make a strong generalization using inductive reasoning, but in order to really prove that it's correct, you would need to test it using other forms of logic.
Induction vs. Deduction in Rhetoric
It's hard to find information about induction without also coming across a similar term: deduction.
Deduction (also called deductive reasoning) is the logical method of drawing specific conclusions based on general observations.
This seems really similar to the definition of induction. So what's the real difference? Induction takes specific observations and broadens them out into a bigger conclusion, while deduction takes a general observation, or premise, and narrows it down to a specific conclusion.
Fig. 2 - The pyramids of inductive and deductive reasoning.
In this graphic, you can see that induction moves from narrow observations to wide conclusions, and deduction moves from wide observations to narrow conclusions. Here's a more concrete example:
Induction:
Specific observation: This instrument has 88 keys.
Specific observation: This instrument is a piano.
General conclusion: Therefore, every piano has 88 keys.
Deduction:
General observation (premise): Every piano has 88 keys.
Specific observation: This instrument is a piano.
Specific conclusion: Therefore, this instrument has 88 keys.
Some words provide clues about inductive vs. deductive reasoning. Notice that the more specific observations and conclusions use words like this, that, one, each, and so on, while the more general observations and conclusions use words like every, all, always, never, and so on. When the more specific words are in the observations, and the more general words are in the conclusions, you're probably looking at inductive reasoning.
If it helps you to understand this from a scientific perspective, think of it this way: induction and deduction represent two parts of the scientific method.
- Induction is involved in the first stage of the scientific method: forming the hypothesis. When you plan an experiment, you start by making observations and taking note of facts. Then, you put your observations together into a hypothesis, which is your idea of what could explain your observations. That's making a general conclusion based on specific observations, a.k.a. induction!
- Deduction is involved in the second stage: testing the hypothesis. You've come to a general conclusion using inductive reasoning. Now you have to test it and draw a specific conclusion that either proves or disproves the hypothesis. That's taking a general premise and narrowing it into a specific conclusion, a.k.a. deduction!
Elements of Inductive Writing
Induction can also play a valuable role in essay writing. In argumentation, synthesis, and rhetorical analysis, induction can help to present information in a logical and persuasive way. These are the key elements of inductive writing.
- Inductive writing allows the reader to come to the conclusion naturally.
- Inductive writing states the facts and observations individually and explains them clearly.
- Inductive writing draws the observations together into a strong and convincing conclusion.
Inductive writing follows the same inverted pyramid pattern as basic inductive reasoning. The specific facts are stated first, and then they are drawn together into a general conclusion.
Synthesis is a good example of inductive writing. A synthesis essay depends on induction to convince the reader of its conclusion. The body paragraphs of a synthesis essay present specific observations by giving information from outside sources. Notice how each of these example body paragraphs adds to the observations.
Data shows that this neighborhood is extremely difficult to traverse on foot. Source A gives the neighborhood a walkability score of 30 out of 100, in contrast to the scores of 75 and 88 given to the two nearest neighborhoods. As new neighborhoods are built with walkability expressly in mind, this historic neighborhood falls further behind.
This lack of walkability doesn't go unnoticed by the neighborhood's residents. In a survey of 35 locals, 27 reported that the lack of sidewalks and traffic control in the neighborhood interferes with everyday life (Source D). The results of the survey shed light on the community's need for ease of transportation.
One story in particular highlights the effect of poor walking conditions on this neighborhood's residents. Dorian Black, a lifelong resident, says, "When I started to lose my vision and could no longer drive, I had no way to leave the house. Thankfully, my daughter is able to bring me groceries and other necessities. But if she weren't available, I would have been forced to leave the community I love for a neighborhood that doesn't rely on cars for travel" (Source C). Unless improvements in walkability are made, residents less fortunate than Dorian will be forced to leave their homes in order to live independently.
The low walkability score, the overall dissatisfaction, and the sad testimonials of residents paint a pessimistic picture for transportation in this historic neighborhood. The issue leads to one conclusion: major infrastructure changes are necessary to make the neighborhood more accessible to pedestrians. Adding well-paved sidewalks to the streets will add security and independence to the treasured community.
The final paragraph puts the observations together and draws a general conclusion.
The body paragraphs in this example introduce the specific observations one by one, building the base of the induction. The first observation is objective data from an outside source. This is a strong observation because the score is based on facts rather than opinions. The second observation shows the results of a survey of local residents. This is also a strong observation because it shows the opinions of the residents while using statistics to demonstrate the scale of the opinions. The last observation is the testimony of one specific resident. This observation takes a personal angle and brings an element of emotion to the argument.
Once the three observations are clearly discussed in the body, the reader is set up to arrive at the conclusion in the final paragraph. The specific points extend out into the larger conclusion: major infrastructure changes are necessary to make the neighborhood more accessible to pedestrians. This conclusion is strong because it follows naturally from the observations. After reading the body paragraphs, the reader already agrees with the writer's conclusion. That's the power of induction in essays!
This example focused on the inductive reasoning of a synthesis essay, but inductive reasoning is useful in any form of persuasive writing! What other uses can you think of for induction in essay writing?
Examples of Induction in Literature
Now you're clear on induction in essays, but what about literature? These are some examples of induction in fiction writing.
Inductive reasoning is often found in the mystery genre. When events start getting suspicious, characters
use induction to speculate about possible patterns.
Fig. 3 - Mysteries often feature induction. Pixabay.
For we are in a trap—I'll take my oath on that! Mrs. Rogers' death! Tony Marston's! The disappearing soldier boys on the dinner table! Oh yes, Mr. Owen's hand is plainly seen ...1
This is a snippet from Chapter 9 of And Then There Were None (1939) by Agatha Christie. The character Philip Lombard makes specific observations: two of the ten guests have died mysteriously within one day, and two of the ten statues have disappeared from the table. Then he brings the observations together into a broader conclusion: all of the characters have been lured into a trap and will be killed one by one. This is a generalization because he observes something happening to two people and concludes that it will happen to everyone else too.
Inductive reasoning shows up multiple times in this novel as the characters make more and more guesses about who the murderer is. The deduction comes later, as the suspects are ruled out, and the mystery gets closer to only one possible conclusion.
Another example of induction in literature is evident in the following passage from Part One of The Alchemist (1993) by Paulo Coelho.
Maybe the church, with the sycamore growing from within, had been haunted. It had caused him to have the same dream for a second time, and it was causing him to feel anger toward his faithful companions.2
The main character makes specific observations here: he slept under the same tree in a ruined church for two nights in a row, and he had the same dream both nights. On top of that, he's starting to get angry for no apparent reason at the sheep that he herds. He brings those observations together into a bigger conclusion: the ruined church and the tree caused nightmares and misplaced anger because they are haunted. The character is making a causal inference here, as he notices a correlation and assumes a causal relationship.
Is the ruined church really haunted? Well, the book never says for sure, and the main character's inductive reasoning doesn't prove whether it's haunted or not. What it does do is help the reader understand the character and build the reader's curiosity about the story.
Induction - Key Takeaways
- Induction (also called inductive reasoning) is the logical method of drawing general conclusions based on specific observations.
- Induction is used in everyday life and in formal rhetoric to make predictions, generalizations, causal inferences, and other conclusions.
- Induction takes specific observations and broadens them out into a bigger conclusion, while deduction takes a general observation, or premise, and narrows it down to a specific conclusion.
- Inductive writing allows the reader to come to the conclusion naturally by clearly stating the observations and then drawing them together into a convincing conclusion.
- Induction is useful in literature too: it can build suspense in a mystery, display a character's thoughts and motivation, and build curiosity about the conclusion of a story.
References
- Agatha Christie, And Then There Were None, 1939
- Paulo Coelho, The Alchemist, 1993
Explanations 
Textbooks 
Exams 
Magazine 
