Thinking: Exploring Mental Life 129tions that led him to formulate the heliocentric theory of the solar system. About
150 years ago the botanist Gregor Mendel raised sweet peas, studied the charac-
teristics of their flowers, and formulated his theory of heredity.
When a detective gathers clues and reaches the conclusion that the butler
murdered the millionaire, the sleuth is using inductive logic. (When Dr. Watson
asks Sherlock Holmes how he reached a conclusion, Holmes answers, “Deduc-
tion, my dear Watson. Merely deduction.” Strictly speaking, he was using induc-
tion, not deduction.)
Inductive reasoning also appears frequently in everyday life. Harold makes a
series of observations about his car. It’s using too much gas, it’s pulling to the left,
it’s overheating, it’s squeaking too much, and the brakes are mushy. He concludes
that it’s overdue for servicing. Or perhaps he concludes that he needs a new car.
Rowena makes a series of observations about her fifteen-year-old daughter, Geor-
gia. Her grades are falling, she is spending more time than usual talking secretively
on the phone with one of her friends, she is dressing very carefully for school, she
is reading romance novels, and she seems unusually dreamy-eyed. Perhaps
Rowena, using inductive reasoning, reaches the conclusion that Georgia is devel-
oping an interest in adolescent males.(a) Logical thinking is thinking that employs to reach a correct conclusion.(b) What kind of reasoning is characterized by making observations and gathering informa-
tion until a general conclusion is reached?
Answers: (a) valid reasoning; (b) Inductive reasoning.
Deductive reasoning is reasoning in which a conclusion follows from a
premise. The underlying structure of deductive reasoning is if-then.Such reasoning
allows for predictions, and it is often the next step taken after inductive reasoning
is employed. Sherlock Holmes tells Dr. Watson, “If the butler is really the mur-
derer, then if we hide in the closet we should see him sneak into Jillian’s bedroom
when the clock strikes midnight.” Rowena thinks, “If Georgia is getting interested
in boys, then it won’t be long before she will be asking me if she can go on a date.”
According to Freud, there is a kind of thinking employed at the unconscious
level of the mind that is overly primitive. It is neither inductive nor deductive.
Freud called this kind of thinking predicate thinking.It is also called paleolog-
ical thought,meaning “old” thought. It is presumably the kind of thinking used
by primitive, prescientific people and by preschool children. According to Freud,
when two sentences have identical predicates (i.e., “first parts”) the objects or peo-
ple in the sentences become associated in an illogical manner. Here is an example:- Automobile make X is driven by beautiful people.
- Automobile make X is the kind of car I drive.
- Therefore I am a beautiful person.