Theories of truth

Suppose you think that the only truths are true by definition. Which of the following statements would be true?

• A right angle is 90°.

• The latitude of the equator is 0°.

• Saints and heroes do not limit themselves to the performance of duty.

• It is better to give than to receive.

Suppose you think that the only truths are truths by adequacy (or correspondence). Which of the following statements would be true?

• Francis I's statement: "My kingdom for a horse", made after his horse had been killed in battle.

• Caesar's statement: "I came, I saw, I conquered", made after he had seen Gaul and conquered it.

• The statement: "Socrates is mortal", made after having said "All men are mortal" and "Socrates is a man".

• John Adams' statement: "Jefferson is still alive", after having maintained a long correspondence with Jefferson.

Suppose you think that the only truths are truths that are coherent with the total knowledge that is accepted as true. Which of the following statements would be true?

• If a new planet were discovered in our solar system, it might have rings but not a long tail.

• If the fossil of a skeleton is found, the skeleton must belong to a being that was once alive.

• If a person speaks Portuguese, everything he says is Portuguese.

• If a couple of giraffe calves are born, the baby giraffes may be hippopotamuses.

Identify which of the theories is involved in the example: The statement: "The grass is green", is true if the grass is green.

• correspondence

• coherence

• pragmatics

• authority

Identify which of the theories is involved in the example: There is nothing in the system of arithmetic that can be in contradiction with saying that "two plus two equals four".

• correspondence

• coherence

• pragmatics

• authority

Identify which of the theories is involved in the example: Since cats really have fur, the statement "Cats have fur" is true.

• correspondence

• coherence

• pragmatics

• authority

Identify which of the theories is involved in the example: To say that a right angle is more or less than 90º would be in contradiction with many things in Euclidean geometry.

• correspondence

• coherence

• pragmatics

• authority

Identify which of the theories is involved in the example: Copernicus was perplexed. The theory that the Sun revolved around the Earth was very confusing and complicated. He wanted a simpler and better theory. When he saw how the theory that it was the Earth that revolved around the Sun explained the facts, "Aha! This one is true!"

• correspondence

• coherence

• pragmatics

• authority