Critical Thinking Assignment: Argument Validity

Given the premises, discuss whether the conclusion of each argument that follows is (a) true beyond a reasonable doubt, (b) probably true, or (c) possibly true or possibly false. You should expect disagreement on these items, but the closer your answers are to your instructor’s, the better.

1. The sign on the parking meter says “Out of Order,” so the meter isn’t working.
The conclusion of this statement is probably true. While the sign on the meter currently says “Out of Order,” there are few things in life that are true beyond a reasonable doubt. The meter is probably out of order.

2. The annual rainfall in California’s north valley averages twenty-three inches. So the rainfall next year will be twenty-three inches.
The conclusion of this statement is probably true. While the region has averaged 23 inches of rainfall a year, this is just an average. For example, 2 years ago it might have rained only 22 inches and the next it rained 24 inches making it a 23 inch average.

3. You expect to get forty miles to the gallon in that? Why, that old wreck has a monster V8; besides, it’s fifty years old and needs an overhaul.
The conclusion of this statement is probably true. The speaker makes valid points arguing against good fuel economy i.e. the vehicle having a V8 engine, the vehicle is old, and it needs an overhaul. While the speaker’s comments are biased, emotional, and possibly exaggerated, they are most likely true.

4. In three of the last four presidential races, the winner of the Iowa Republican primary has not captured the Republican nomination. Therefore, the winner of the next Iowa Republican primary will not capture the Republican nomination.
The conclusion of this statement is possibly true or possibly false. While some states have more emphasis than others in the primaries, it appears that the winner of the Iowa Republican primary not winning the Republican nomination is more coincidence than anything. It is possible the winner of the primary this year may not win the nomination but not necessarily probable.

5. The New York steak, the Maine lobster, and the beef stroganoff at that restaurant are all exceptionally good. All the entrees are excellent.
The conclusion of this statement is possibly true or possibly false. While the steak, lobster, and stroganoff are all exceptionally good, it does not mean that all of the entrees are going to be excellent. If the chef cooks the steak, lobster and beef stroganoff well, it is likely that they also cook the other entrees well; however taste is a matter of opinion and the reader might not like the same entrees, let alone all the entrees.

6. The number of cellular telephones has increased dramatically in each of the past few years. Therefore there will be even more of them in use this coming year.
The conclusion of this statement is true beyond a reasonable doubt. It only takes one person to purchase and use a cell phone for there to be more cell phones in use than the prior year; the odds of this not happening are astronomical therefore it is true beyond a reasonable doubt (the key word being reasonable).

7. Since the graduates of Harvard, Yale, Princeton, and other Ivy League schools generally score higher on the Graduate Record Examination than students from Central State, it follows that the Ivy League schools do more toward educating their students than Central State does.
The conclusion of this statement is probably true. While there can be other variables taken into consideration (i.e. the demographics of the students attending either school or taking the test), there are not enough concrete variables to swing this to either true beyond a reasonable doubt or possibly true or possibly false.

8. Michael Jackson has had more plastic surgery than anybody else in California. You can bet he’s had more than anybody in Connecticut!
The conclusion of this statement is possibly true or possibly false. While it’s not confirmed exactly how much plastic surgery Jackson has had, it is doubtful that no one in California has had more than him. However, it is proven that more people have had plastic surgery in California than Connecticut.

9. Although Max bled profusely before he died, there was no blood on the ground where his body was found. Therefore, he was killed somewhere else and brought here after the murder.
The conclusion of this statement is possibly true or possibly false. Murders are one of the most investigated events in the world; tragically some of societies most creative moments were in murders. There could be any number of reasons to explain why there is no blood on the ground i.e. the victim was killed on a tarp then the tarp removed.

10. When liquor was banned in 1920, hospitalizations for alcoholism and related diseases plummeted; in 1933, when Prohibition was repealed, alcohol-related illnesses rose sharply again. Legalization of cocaine, heroin, and marijuana would not curb abuse of those substances.
The conclusion of this statement is probably true. While you can compare different variables such as the presence of speakeasies was a fraction compared to the current drug and drug trafficking empire, the results are still fairly straightforward.

11. Relax. The kid’s been delivering the paper for, how long? Three, four years maybe? And not once has she missed us. The paper will be here, just wait and see. She’s just been delayed for some reason.
The conclusion of this statement is probably true. While anything is possible and the “kid” could have quit, have been injured or worse, the fact remains that she will likely still deliver the paper. Again, there is little in life that is true beyond a reasonable doubt therefore this is not a satisfactory option.

12. First, it seems clear that even if there are occasional small dips in the consumption of petroleum, the general trend shows no sign of a real permanent decrease. Second, petroleum reserves are not being discovered as fast as petroleum is currently being consumed. From these two facts we can conclude that reserves will eventually be consumed and that the world will have to do without oil.
The conclusion of this statement is possibly true or possibly false. It seems that this text was written before our current oil crisis and in March 2008, Americans drove 11 billion less miles than they did in March 2007 – the largest yearly drop ever recorded since 1942. Also, while reserves are not being discovered as fast as petroleum is being consumed, the reader has to reflect on the age old adage “quality over quantity”. Rather than being concerned with the number of oil fields being discovered, one should look at the size of oil fields being discovered. However, there is no way to tell whether the world will be required to become completely oil free or not.