Each of the following is an argument ‘in the wild’ – that is, an argument that appears not merely as an example in a critical thinking subject. As such, the arguments are not always presented in standard form and they may contain important unstated premises.
For each of the arguments:
- Set them out in standard form;
- State explicitly any implicit premises;
- Identify the kind of argument;
- (1) If it is a deductive argument, assess whether or not it is valid.
(2) If it is an inductive argument, say whether the premises support the conclusion strongly or only weakly and why.
Below are two examples
Now if Christ is preached as raised from the dead, how can some of you say that there is no resurrection of the dead? But if there is no resurrection of the dead, then Christ has not been raised. … But in fact Christ has been raised, the first fruits of those who have fallen asleep.
- If there is no resurrection of the dead, then Christ has not been raised from the dead.
- But Christ has been raised from the dead.
Therefore, there is resurrection from the dead.
There are no important unstated premises. This is a deductive argument. It is valid.
Just as the Bush administration launched the invasion of Iraq without making sure that they had enough troops to deal with the next stage of the operation (the occupation and reconstruction), Obama is withdrawing without thinking about the numbers of troops required to protect State Department employees and others tasked with continuing the reconstruction of Iraq beyond 2011.
- The decision by Bush to invade Iraq resembles Obama’s decision about withdrawing from with respect to not thinking about whether there will be enough troops for the next stage of the mission.
- Bush’s decision was a bad decision. [Unstated premise]
So, probably, Obama’s decision is a bad decision too.
Premise 2 is an important, unstated premise. This is an analogical argument, but the premise doesn’t support the conclusion very strongly since it pays attention to only one similarity between the two decisions and, in addition, it ignores a relevant difference. Invading is very different from withdrawing.
But the peculiar evil of silencing the expression of an opinion is, that it is robbing the human race; posterity as well as the existing generation; those who dissent from the opinion, still more than those who hold it. If the opinion is right, they are deprived of the opportunity of exchanging error for truth: if wrong, they lose, what is almost as great a benefit, the clearer perception and livelier impression of truth, produced by its collision with error. (John Stuart Mill, On Liberty)
Question 2[Sherlock Holmes is speaking to Dr Watson] “Nothing of the sort. I knew you came from Afghanistan. From long habit the train of thoughts ran so swiftly through my mind that I arrived at the conclusion without being conscious of intermediate steps. There were such steps, however. The train of reasoning ran, ‘Here is a gentleman of a medical type, but with the air of a military man. Clearly an army doctor, then. He has just come from the tropics, for his face is dark, and that is not the natural tint of his skin, for his wrists are fair. He has undergone hardship and sickness, as his haggard face says clearly. His left arm has been injured. He holds it in a stiff and unnatural manner. Where in the tropics could an English army doctor have seen much hardship and got his arm wounded? Clearly in Afghanistan.’ The whole train of thought did not occupy a second. I then remarked that you came from Afghanistan, and you were astonished.” (Sir Arthur Conan Doyle, A Study in Scarlet)
On December 5, 1945 US Navy Flight 19 with five aircraft was lost in the Bermuda Triangle without a trace. On the same day, a seaplane sent out to search for them was also lost without a trace. The USS Cyclops was also lost without a trace in this region in 1918. The USS Proteus was lost in 1941 with all 51 people aboard and in 1963 the SS Marine Sulphur Queen similarly vanished with the loss of 39 crewmen. No wreckage from either vessel was ever found. The Bermuda Triangle is a uniquely sinister place – an area on the map unlike any other, where ships and planes regularly vanish without a trace. (Alexander Cranque, The Devil’s Triangle: a mystery unsolved, Pharse Publishing 2004)
Not all soil animals are beneficial. Some beetle and fly larvae are serious crop pests. (Clive Edwards, ‘Soil Pollutants and Soil Animals’, Scientific American, April, 1969