1. Psychology Is Alive and Well (and Doing Fine Among the Sciences)

The Freud Problem

The Diversity of Modern Psychology

Implications of Diversity

Unity in Science

What, Then, Is Science?

Systematic Empiricism

Publicly Verifiable Knowledge: Replication and Peer Review

Empirically Solvable Problems: Scientists’ Search for Testable Theories

Psychology and Folk Wisdom: The Problem with “Common Sense”

Psychology as a Young Science

Summary

2. Falsifiability: How to Foil Little Green Men in the Head

Theories and the Falsifiability Criterion

The Theory of Knocking Rhythms

Freud and Falsifiability

The Little Green Men

Not All Confirmations Are Equal

Falsifiability and Folk Wisdom

The Freedom to Admit a Mistake

Thoughts Are Cheap

Errors in Science: Getting Closer to the Truth

Summary

3. Operationism and Essentialism: “But, Doctor, What Does It Really Mean?”

Why Scientists Are Not Essentialists

Essentialists Like to Argue About the Meaning of Words

Operationists Link Concepts to Observable Events

Reliability and Validity

Direct and Indirect Operational Definitions

Scientific Concepts Evolve

Operational Definitions in Psychology

Operationism as a Humanizing Force

Essentialist Questions and the Misunderstanding of Psychology

Operationism and the Phrasing of Psychological Questions

Summary

4. Testimonials and Case Study Evidence: Placebo Effects and the Amazing Randi

The Place of the Case Study

Why Testimonials Are Worthless: Placebo Effects

The “Vividness” Problem

The Overwhelming Impact of the Single Case

The Amazing Randi: Fighting Fire with Fire

Testimonials Open the Door to Pseudoscience

Summary

5. Correlation and Causation: Birth Control by the Toaster Method

The Third-Variable Problem: Goldberger and Pellagra

Why Goldberger’s Evidence Was Better

The Directionality Problem

Selection Bias

Summary

6. Getting Things Under Control: The Case of Clever Hans

Snow and Cholera

Comparison, Control, and Manipulation

Random Assignment in Conjunction with Manipulation Defines the True Experiment

The Importance of Control Groups

The Case of Clever Hans, the Wonder Horse

Clever Hans in the 1990s

Prying Variables Apart: Special Conditions

Intuitive Physics

Intuitive Psychology

Summary

7. “But It’s Not Real Life!”: The “Artificiality” Criticism and Psychology

Why Natural Isn’t Always Necessary

The “Random Sample” Confusion

The Random Assignment Versus Random Sample Distinction

Theory-Driven Research Versus Direct Applications

Applications of Psychological Theory

The “College Sophomore” Problem

The Real-Life and College Sophomore Problems in Perspective

Summary

8. Avoiding the Einstein Syndrome: The Importance of Converging Evidence

The Connectivity Principle

A Consumer’s Rule: Beware of Violations of Connectivity

The “Great-Leap” Model Versus the Gradual-Synthesis Model

Converging Evidence: Progress Despite Flaws

Converging Evidence in Psychology

Scientific Conse