Induction

Definition of Induction

Induction starts with specific facts and draws conclusions, which may be right or wrong. This is a type of reasoning that assumes that given premises strongly lead to a certain conclusion, but there is not enough evidence to make this conclusion definite, only probable. The danger of inductive reasoning is that it is uncertain and often simplistic, and can lead to certain types of fallacy and over-generalization. However, it can lead to accurate conclusions as well, though one must always be careful to understand that the conclusion is not necessarily true.

The word induction comes from the Latin word inductio, which means “a leading in, introduction, admission.”

Difference Between Induction, Deduction, and Abduction

The definition of induction is similar to that of deduction and abduction as they are all methods of reasoning. However, whereas induction starts with known instances and arrives at a generalization, deduction involves a general principle or principles and arrives at a specific fact. This is an important distinction, because induction is much more vulnerable to fallacies while deduction leads to logically certain conclusions.

Abduction is similar to induction as they both arise from specific observations. In abductive reasoning, however, the logician attempts to create a simple theory that could explain the observation without making an overall generalization. The conclusion that abductive reasoning draws may not be true, but instead it is an inference that leads to the best possible explanation given the circumstances.

Common Examples of Induction

We use inductive reasoning frequently in daily life, for better or worse. Here are some common examples of inductive reasoning:

• I got coffee once at the cafe and it was horrible, so all of their coffee must be terrible.
• She’s been married twice and divorced twice; she must be a difficult wife.
• This winter is colder than ever, therefore global warming must not be real.

Significance of Induction in Literature

There are some examples of induction in literature, especially where there are courtroom scenes, or where characters try to reason through a problem. In some mystery novels a red herring will lead to induction that guides the characters off course. However, we also sometimes use induction examples in our own reading experience. We may read about one character and generalize from their specific behavior toward all people like them. For example, if you’d only read a few novels, and one of them included a character from China, you might use inductive reasoning to assume that all characters or ever people from China would act and think similarly. This leads to the importance of reading literature widely, so as to avoid the sense that there is only “one story” when it comes to any group of people.

Examples of Induction in Literature

Example #1

The witnesses for the state, with the exception of the sheriff of Maycomb County, have presented themselves to you gentlemen, to this court, in the cynical confidence that their testimony would not be doubted, confident that you gentlemen would go along with them on the assumption—the evil assumption—that all Negroes lie, that all Negroes are basically immoral beings, that all Negro men are not to be trusted around our women, an assumption one associates with minds of their caliber.
“Which, gentlemen, we know is in itself a lie as black as Tom Robinson’s skin, a lie I do not have to point out to you. You know the truth, and the truth is this: some Negroes lie, some Negroes are immoral, some Negro men are not to be trusted around women—black or white. But this is a truth that applies to the human race and to no particular race of men.

(To Kill a Mockingbird by Harper Lee)

Atticus Finch, the father of the protagonist and narrator, is the defense lawyer in Harper Lee’s To Kill a Mockingbird. He is defending a man named Tom Robinson, who is clearly innocent of the crime he’s accused of. Atticus uses the fact that Tom is right-handed and that the beating in question was inflicted by a left-handed person to prove this. However, he goes further here to show that the only case against Tom is based on inductive reasoning. The prosecutors are trying to use inductive reasoning to prove, as Atticus says, “that all Negroes lie, that all Negroes are basically immoral beings, that all Negro men are not to be trusted around our women.” This is a dangerous example of induction, because it will lead to incriminating an innocent man.

Example #2

GUILDENSTERN: It must be indicative of something, besides the redistribution of wealth. (He muses.) List of possible explanations. One: I’m willing it. Inside where nothing shows, I’m the essence of a man spinning double-headed coins, and betting against himself in private atonement for an unremembered past. (He spins a coin at ROS.)
ROSENCRANTZ: Heads.
GUILDENSTERN: Two: time has stopped dead, and a single experience of one coin being spun once has been repeated ninety times… (He flips a coin, looks at it, tosses it to ROS.) On the whole, doubtful. Three: divine intervention, that is to say, a good turn from above concerning him, cf. children of Israel, or retribution from above concerning me, cf. Lot’s wife. Four: a spectacular vindication of the principle that each individual coin spun individually (he spins one) is as likely to come down heads as tails and therefore should cause no surprise that each individual time it does. (It does. He tosses it to ROS.)

(Rosencrantz and Guildenstern are Dead by Tom Stoppard)

In Tom Stoppard’s absurdist play Rosencrantz and Guildenstern are Dead, the two main characters are confronted with the bizarre occurrence of a penny being flipped and landing on heads ninety-two times in a row. In this excerpt Guildenstern begins to use inductive reasoning to understand what might be happening, and arrives at different fallacious conclusions until he his fourth conclusion, which can be the only one supported with logic.

Example #3

“Blasted thing,” Snape was saying. “How are you supposed to keep your eyes on all three heads at once?”
….
“You know what this means?” [Harry Potter] finished breathlessly. “He tried to get past that three-headed dog at Halloween! That’s where he was going when we saw him—he’s after whatever it’s guarding! And I’d bet my broomstick he let that troll in, to make a diversion!”

(Harry Potter and the Sorcerer’s Stone by J. K. Rowling)

In the first installment of J. K. Rowling’s Harry Potter series, the protagonist Harry makes a few enemies, including his teacher, Professor Snape. He knows that Snape hates him and treats him cruelly. However, he uses these small, personal experiences to extrapolate that Snape is indeed evil and must be trying to break in to a secret room in Hogwarts Castle. In this induction example, Harry uses his own personal grudge to lead to the false conclusion that Snape is in cahoots with Lord Voldemort.

Test Your Knowledge of Induction

1. Which of the following statements is the correct induction definition?
A. A type of reasoning which leads from specific incidents and attempts to make a broader generalization.
B. A manner of thinking in which general principles are are applied to specific situations to understand them.
C. A type of fallacy in which the reasoning has no basis in reality.

2. Which of the following statements is true?
A. The conclusions reached from inductive reasoning are always true.
B. The conclusions reached from deductive reasoning are never true.
C. The conclusions reached from inductive reasoning may be true, but are not necessarily so.

3. Consider the following quote from Sir Arthur Conan Doyle’s Sherlock Holmes series:

“How do I know that you have been getting yourself very wet lately, and that you have a most clumsy and careless servant girl?”
….
“It is simplicity itself,” said he; “my eyes tell me that on the inside of your left shoe, just where the firelight strikes it, the leather is scored by six almost parallel cuts. Obviously they have been caused by someone who has very carelessly scraped round the edges of the sole in order to remove crusted mud from it. Hence, you see, my double deduction that you had been out in vile weather, and that you had a particularly malignant boot-slitting specimen of the London slavey.”

What type of reasoning does Sherlock Holmes employ in this example?
A. Inductive reasoning: Holmes notices small things and makes sweeping generalizations based on them.
B. Abductive reasoning: Holmes makes intelligent observations and creates a theory of what was most likely to have happened.
C. Deductive reasoning: Holmes sees larger principles at work and deduces a logically certain conclusion.