Philosophy 251: Handout #1

I. Extract the argument(s) from each of the following passages and put the arguments into standard form.

1. If temporal moments have no parts, then no one can travel in time. Temporal moments have no parts. Therefore, no one can travel in time.

2. The sun has risen every day prior to today. The sun rose today, so the sun will rise tomorrow.

3. Abigail hits 80% of the targets she shoots at and Harry hits 90% of the targets he shoots at. Both will shoot at that target, so that target will get hit.

4. Having cancer is a good, for whatever is required by something that is good is itself a good. Being cured of cancer is a good, and being cured of cancer requires having cancer.

5. God predestines human acts only if God fully causes human acts. God fully causes human acts only if humans lack free will. So, God predestines human acts only if humans lack free will. But humans do not lack free will, so God does not predestine human acts.

6. Obviously, empirical data are scientific. But only what can be falsified is scientific, and so, although many people regard empirical data as fixed and unchangeable, empirical data can be falsified.

7. It is not possible that a thing be the efficient cause of itself; for if a thing were the efficient cause of itself it would be prior to itself; but nothing is prior to itself. Also, if there be no first cause among efficient causes there will be no ultimate effect nor any intermediate cause, but it is plainly false that there is no ultimate effect or intermediate cause. Hence, the order of efficient causes cannot go on to infinity. Therefore, it is necessary to admit a first efficient cause, to which everyone gives the name God. --Thomas Aquinas

8. Either potential murderers are rational enough to be deterred by the death penalty or they are not. If not, then the death penalty is not necessary. If potential murderers are rational enough to be deterred by the death penalty, then they are rational enough to be deterred by life imprisonment, and if they are rational enough to be deterred by life imprisonment, the death penalty is not necessary. Either way the death penalty is not necessary and so should be abolished, for if the death penalty isn't necessary it should be abolished.

9. Either Socrates corrupts the youth or he does not. If not, then Socrates ought to be acquitted. If he does corrupt the youth, then either he does so willingly or unwillingly. If Socrates willingly corrupts the youth, then Socractes willingly makes it likely that he himself will be harmed, for harming one's associates is sufficient for making it likely that oneself will be harmed. But Socrates does not willingly make it likely that Socrates will be harmed. On the other hand, if Socrates corrupts the youth unwillingly, then Socrates ought to be instructed. Thus, either Socrates ought to be instructed or acquitted.

II. Which of the following are true and which are false?

1. No argument with a false conclusion is valid.
2. Every argument with a true conclusion is valid.
3. Any argument with all true premises and a true conclusion is valid.
4. Any argument with all true premises and a false conclusion is invalid.
5. A sound argument can have a false conclusion.
6. A sound argument can have a false premise.