Deductive and Inductive Arguments

Because triangle A is congruent with triangle B, and triangle A is isosceles, it follows that triangle B is isosceles.

• deductive

• inductive

The plaque on the leaning tower of Pisa says that Galileo performed experiments

there with falling objects. It must be the case that Galileo did indeed perform those experiments there.

• deductive

• inductive

The rainfall in Seattle has been more than 15 inches every year for the past thirty years. Therefore, the rainfall next year will probably be more than 15 inches.

• Inductive

• Deductive

No E-mail messages are eloquent creations. Some love letters are eloquent creations. Therefore, some love letters are not E-mail messages.

• Deductive

• Inductive

Petron, BP, and Shell are all listed on the World Stock Exchange. It must be the case that all major oil companies are listed on the World Stock Exchange.

(a)  

The longer a pendulum is, the longer it takes to swing. Therefore, when the pendulum of a clock is lengthened, the clock slows down.

• Deductive

• Inductive

Paying off terrorists in exchange for hostages is not a wise policy, since such action will only lead them to take more hostages in the future.

• Deductive

• Inductive

The Everest Mount is higher than Mount K2, and Mount K2 is higher than Mount Khanchenjunga. The obvious conclusion is that the Everest is higher

than Mount Khanchenjunga .

• Deductive

• Inductive

Although both front and rear doors were found open after the burglary, there were pry marks around the lock on the rear door and deposits of mud near the threshold. It must be the case that the thief entered through the rear door

and left through the front.

(a)  

The Encylopaedia Britannica has an article on symbiosis. The Encyclopedia Americana, like the Britannica, is an excellent reference work. Therefore, the Americana probably also has an article on symbiosis.

• Deductive

• Inductive