philosophy.lander.edu

Homepage > Logic > Quizzes > Truth Validity Soundness > Answers     

Directions: Carefully study statements 1-10. Decide whether each statement is true or false and write in the spaces provided the word “true”; or the word “false”; in accordance with your decision.

1. __________ A sound argument is a valid deductive argument with true premisses.

   The statement is true because it's the definition of a sound argument.

2. __________ A deductive argument cannot be both valid and unsound.

   False, because a valid deductive argument might have false premisses.

3. __________ All valid deductive arguments are sound arguments.

   It's false because some valid arguments have false premisses.

4. __________ A deductive argument can be either valid or invalid and still have true premisses.

   It's true because the truth and falsity of premisses are not dependent on the structure of the argument

5. _________ When the conclusion of a deductive argument is true, the argument must be sound.

   It's false, since nothing is said about the truth of the premisses or the validity of the argument.

6. __________ When the premisses of a deductive argument are true, the conclusion is always true as well.

   The conclusion would not always be true unless the argument were valid, so the statement is indeed false.

7. __________ If a deductive argument is sound, then the conclusion must be true.

   Yes, by the definition of a sound argument.

8. __________ A deductive argument could have a false premiss and still be sound.

   It's false by the definition of what a sound argument is.

9. __________ In a valid deductive argument the conclusion could be true or false.

   True, the truth of the conclusion would depend of the truth value of the premisses.

10. __________ An invalid deductive argument could have all true statements in it.

    True, the conclusion could just be true by coincidence. For example, “The sky is blue and grass is green, so you're working this problem now.”

Send corrections or suggestions to larchie[at]philosophy.lander.edu
Read the disclaimer concerning this page.
1997-2024 Licensed under GFDL and Creative Commons 3.0



The “Copyleft” copyright assures the user the freedom to use,
copy, redistribute, make modifications with the same terms.
Works for sale must link to a free copy.

The “Creative Commons” copyright assures the user the freedom
to copy, distribute, display, and modify on the same terms.
Works for sale must link to a free copy.

Arguments | Language | Fallacies  | Propositions  | Syllogisms  | Translation  | Symbolic