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Flashcards in Truth and Rationality Deck (7)
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Interrogative Ex?

1. What time is it?
2. Did you feed the dog?


Imperative Ex?

3. Tell me the time!
4. Feed the dog!


Declarative Ex?

5. 6. 7. 8. 9.
Some gardeners do not use pesticides.
I fed the dog.
Stephen Harper was the Canadian P.M. in 2010. Stephen Harper likes to wear pink jumpsuits.
There are more than 100 billion insects in the world.


Belief Principle

Whenever a person considers any proposition, that person must believe the proposition, or disbelieve the proposition, or suspend judgmentabouttheproposition. Apersoncannotat any time have more than one of these attitudes toward one proposition.


Rational Belief Principle

If a person’s total evidence concerning a proposition supports that proposition, then it is rational for the person to believe the proposition. If the person’s total evidence goes against the proposition, then it rational for the person to disbelieve the proposition. And if the person’s total evidence is neutral, then it is rational for the person to suspend judgment concerning the proposition.


Principle of Proportional Belief (PB):

It is rational to proportion the strength of one's belief to the strength of one's evidence. The stronger one's evidence for a proposition is, the stronger one's belief in it should be.


If two people disagree about a proposition, then either they

have different evidence or (at least) one of them is unjustified (unreasonable, irrational) with respect to that proposition.