Unraveling the mystery of Inductive & Deductive ArgumentsAn Introduction

• What is an Argument?

• What is the difference between an Inductive and Deductive Argument?

• How is this difference related to research?

Sherlockian or Holmesian deduction

“Data! Data! Data!” he cried impatiently. “I can't make bricks without clay.”

“It is a capital mistake to theorise before you have all the evidence. It biases the judgment.”“The temptation to form premature theories upon insufficient data is the bane of our profession.”

What is an Argument?More than an assertion

A series of statements offering reasons and evidence that support an assertion.

3 Parts of an ArgumentPremises – statements

of assumed fact that support a conclusion

Inferences – the reasoning parts of the argument that link the premises with the conclusion

Conclusion – what is drawn from the premises and inferences

Conclusion

InferencesPremises

Example of an assertion:

Upon observing Watson’s scraped shoes, Holmes tells his friend that he has “a most clumsy and careless servant girl.”

How could Holmes have created an argument to support this assertion?

Example of an argument

Premises

• The leather on Watson’s shoe has several cuts in it

• The cuts were caused by someone scraping the shoe

Inferences

• If someone cut his shoes while scraping them, s/he must be careless and clumsy

• A doctor would have a servant girl who scrapes his shoes

Conclusion

• Watson’s servant girl must be careless and clumsy

Deductive & Inductive Arguments

Deduction◦ Logically demonstrating

that a particular principle is true.

◦ Draws on previous knowledge

◦ Starting point is a set of

concepts or a conceptual scheme

◦ “Theory-driven”

◦ “Top-down”

Induction◦ Developing a general

principle from specific cases and observations.

◦ Part of the discovery process

◦ Starting point is the

observation of specific cases

◦ “Data-driven”

◦ “Bottom-up”

Deductive & Inductive Arguments

Deduction◦ Logically demonstrating

that a particular principle is true.

◦ Draws on previous knowledge

◦ Starting point is a set of

concepts or a conceptual scheme

◦ “Theory-driven”

◦ “Top-down”

Induction◦ Developing a general

principle from specific cases and observations.

◦ Part of the discovery process

◦ Starting point is the

observation of specific cases

◦ “Data-driven”

◦ “Bottom-up”

Deductive & Inductive Arguments

Deduction◦ Logically demonstrating

that a particular principle is true.

◦ Draws on previous knowledge

◦ Starting point is a set of

concepts or a conceptual scheme

◦ “Theory-driven”

◦ “Top-down”

Induction◦ Developing a general

principle from specific cases and observations.

◦ Part of the discovery process

◦ Starting point is the

observation of specific cases

◦ “Data-driven”

◦ “Bottom-up”

Deductive & Inductive Arguments

Deduction◦ Logically demonstrating

that a particular principle is true.

◦ Draws on previous knowledge

◦ Starting point is a set of

concepts or a conceptual scheme

◦ “Theory-driven”

◦ “Top-down”

Induction◦ Developing a general

principle from specific cases and observations.

◦ Part of the discovery process

◦ Starting point is the

observation of specific cases

◦ “Data-driven”

◦ “Bottom-up”

Deductive & Inductive Arguments

Deduction◦ Logically demonstrating

that a particular principle is true.

◦ Draws on previous knowledge

◦ Starting point is a set of

concepts or a conceptual scheme

◦ “Theory-driven”

◦ “Top-down”

Induction◦ Developing a general

principle from specific cases and observations.

◦ Part of the discovery process

◦ Starting point is the

observation of specific cases

◦ “Data-driven”

◦ “Bottom-up”

DeductionTheoryTheory

Hypothesis

Observations

Hypothesis

Patterns

ObservationsConclusions

Induction

Theory-Driven Research Grounded Theory

Example: Deduction

Every student in the class has a Facebook page. Sam is a student in the class. Therefore, Sam has a Facebook page.

Begins with a general concept

Ends with a very certain conclusion

Example: Induction

Francine watches Fox News regularly. People who are politically conservative usually enjoy watching Fox. Francine is probably politically conservative.

Begins with a specific observatio

n

Draws an uncertain but probable conclusion using informal or everyday argument

Example: Induction

Francine watches Fox News regularly. People who are politically conservative usually enjoy watching Fox. Francine is probably politically conservative.

Inference

Example: Induction

Francine watches Fox News regularly. People who are politically conservative usually enjoy watching Fox. Francine is probably politically conservative.

Draws an uncertain but probable conclusion using informal or everyday argument

Induction or Deduction?According to Social Cognitive Theory, people

learn by watching what others do. These “others” serve as models for behavior. This modeling can be interpersonal as well as mediated. Therefore, when Bobby watches his favorite characters on TV, the behaviors they model can influence his behavior.

A. Induction

B. Deduction

Induction or Deduction?A sample of 200 students at a large

northeastern university revealed that 175 students (87.5%) have used their phones to text their friends during class. Thus, if you are teaching a class, you can expect close to 88% of your students to be texting while you’re teaching.

A. Induction

B. Deduction

Deduction & Induction:One or the other? In practice, deduction often includes

elements of induction and vice versa. ◦ Rooted in theoretical reflection

Both persuasive

Deductive arguments are “truth-preserving”

Inductive arguments open us to knew ideas and expand our knowledge

Work together

Scene of the Crime