Table T-1

Contrasting Theory and Common Sense on Criteria Used to Evaluate Theory

Good Theory

Common Sense

Internally consistent (avoids contradicting itself; no "double talk").

Makes contradictory statements.

Consistent with existing facts.(A theory not grounded in fact is just a fantasy.)

Not overly concerned with being consistent with existing facts.

May make novel, counter-intuitive predictions.

Makes intuitively obvious, commonsense          predictions.

Summarizes, explains, and organizes facts.

Summarizes, but not as extensively or accurately as theories. Furthermore, some studies derived from intuition yield results than cannot be integrated with existing knowledge.

Stimulates research by focusing attention on a particular set of problems and by making novel, counter-intuitive predictions.

Rarely focuses research on a problem.

Parsimonious (economical: a few principles explain many events).

Parsimonious, often to the point of grossly oversimplifying reality.

Testable because it makes clear, specific predictions and provides operational definitions of key variables. Beware of (a) quack theories that are hard to understand because the author has created unclear jargon ("gobbledygook"), (b) theories that are so vague that it is hard to say what they are predicting, (c) any theory that makes more than one prediction for what will happen in a certain situation, and (d) any theory that uses concepts (e.g., "vibes") that cannot be objectively measured or manipulated.

Sometimes not testable because commonsense predictions may predict all possible outcomes, are too vague, or key variables can’t be measured.

Good Theory	Common Sense
Internally consistent (avoids contradicting itself; no "double talk").	Makes contradictory statements.
Consistent with existing facts.(A theory not grounded in fact is just a fantasy.)	Not overly concerned with being consistent with existing facts.
May make novel, counter-intuitive predictions.	Makes intuitively obvious, commonsense predictions.
Summarizes, explains, and organizes facts.	Summarizes, but not as extensively or accurately as theories. Furthermore, some studies derived from intuition yield results than cannot be integrated with existing knowledge.
Stimulates research by focusing attention on a particular set of problems and by making novel, counter-intuitive predictions.	Rarely focuses research on a problem.
Parsimonious (economical: a few principles explain many events).	Parsimonious, often to the point of grossly oversimplifying reality.
Testable because it makes clear, specific predictions and provides operational definitions of key variables. Beware of (a) quack theories that are hard to understand because the author has created unclear jargon ("gobbledygook"), (b) theories that are so vague that it is hard to say what they are predicting, (c) any theory that makes more than one prediction for what will happen in a certain situation, and (d) any theory that uses concepts (e.g., "vibes") that cannot be objectively measured or manipulated.	Sometimes not testable because commonsense predictions may predict all possible outcomes, are too vague, or key variables can’t be measured.