The goal of a critical thinking course is to enable you to understand and analyze arguments. By the end of the course you should be able to recognize such arguments and determine if they are good (i.e. if a rational person, upon hearing such an argument, should be convinced by it.)
1. Basics of Argumentation
Argument: An attempt to convince, using reasons4. An argument consists of two parts:
A conclusion, which is the sentence that the argument is arguing for, or that part of the argument that the arguer is trying to convince you of. The conclusion is always a claim.
The premises. These are sentences that are supposed to support, lead to, provide evidence for, prove or convince that the conclusion is true. An argument is an attempt to convince someone (though not necessarily someone in particular) that a certain claim is true.
For example, this is an argument:
Mr. Johnson’s fingerprints, and only Mr. Johnson’s fingerprints, were found at the crime scene. A knife was found on Mr. Johnson’s person, and it matched the wounds on the victim, and contained traces of the victim’s blood. Mr. Johnson’s cellmate testified that Mr. Johnson confessed to the crime, and hidden cameras recorded this confession. Therefore, Mr. Johnson is guilty.
The last sentence is the conclusion. The other sentences are premises. Here’s another:
When I left the house there was cake in the refrigerator. You’re the only other person with a key to the house, and now the cake is gone. So you ate the cake.
Again, the last sentence is the conclusion, the others are premises. Here’s another:
You should complete your college education. People who graduate from college not only earn, on average, more money than college dropouts, they also report much higher levels of satisfaction in life.
In this case, the first sentence is the conclusion, and the rest are premises. You should be able to note this because the other sentences give reasons that you should accept the first sentence. That is, they act as premises, or evidence, for the conclusion. Another way to see that this is the conclusion is to ask yourself: what is the person trying to convince me of? It’s not “college graduates earn more money.” He’s telling me that without any evidence. But, if that’s true, that’s a reason to graduate from college. In other words, it’s a premise. The premise is presented as evidence for the conclusion.
The Trolley Problem5
The trolley problem: should you pull the lever to divert the runaway trolley onto the side track?
The trolley problem is a thought experiment in ethics. The general form of the problem is this: There is a runaway trolley barreling down the railway tracks. Ahead, on the tracks, there are five people tied up and unable to move. The trolley is headed straight for them. You are standing some distance off in the train yard, next to a lever. If you pull this lever, the trolley will switch to a different set of tracks. However, you notice that there is one person on the side track. You have two options: (1) Do nothing, and the trolley kills the five people on the main track. (2) Pull the lever, diverting the trolley onto the side track where it will kill one person. Which is the most ethical choice?
The modern form of the problem was first introduced by Philippa Foot in 1967, but also extensively analyzed by Judith Thomson, Frances Kamm, and Peter Unger. However an earlier version, in which the one person to be sacrificed on the track was the switchman's child, was part of a moral questionnaire given to undergraduates at the University of Wisconsin in 1905, and the German Hans Welzel discussed a similar problem in 1951. Outside of the domain of traditional philosophical discussion, the trolley problem has been a significant feature in the fields of cognitive science and, more recently, of neuroethics. It has also been a topic in popular books dealing with human psychology. The problem is also discussed with regards to the ethics of the design of autonomous vehicles.
Foot's original structure of the problem ran as follows:
Suppose that a judge or magistrate is faced with rioters demanding that a culprit be found for a certain crime and threatening otherwise to take their own bloody revenge on a particular section of the community. The real culprit being unknown, the judge sees himself as able to prevent the bloodshed only by framing some innocent person and having him executed. Beside this example is placed another in which a pilot whose airplane is about to crash is deciding whether to steer from a more to a less inhabited area. To make the parallel as close as possible it may rather be supposed that he is the driver of a runaway tram which he can only steer from one narrow track on to another; five men are working on one track and one man on the other; anyone on the track he enters is bound to be killed. In the case of the riots the mob have five hostages, so that in both examples the exchange is supposed to be one man's life for the lives of five.
A utilitarian view asserts that it is obligatory to steer to the track with one man on it. According to simple utilitarianism, such a decision would be not only permissible, but, morally speaking, the better option (the other option being no action at all). An alternate viewpoint is that since moral wrongs are already in place in the situation, moving to another track constitutes a participation in the moral wrong, making one partially responsible for the death when otherwise no one would be responsible. An opponent of action may also point to the incommensurability of human lives. Under some interpretations of moral obligation, simply being present in this situation and being able to influence its outcome constitutes an obligation to participate. If this is the case, then deciding to do nothing would be considered an immoral act if one values five lives more than one.