ARGUMENT

Argument To give an argument is to provide a set of premises as reasons for accepting the conclusion. Do these passages contain arguments? If so, what are their conclusions? Cutting the interest rate will have no effect on the stock market this time round as people have been expecting a rate cut all along. This factor has already been reflected in the market. Yes. The conclusion is that this time, cutting interest rate will have no effect on the stock market.

Argument So it is raining heavily and this building might collapse. But I don't really care. Not an argument. Although the first statement starts with "so" it does not indicate a conclusion. Virgin would then dominate the rail system. Is that something the government should worry about? Not necessarily. The industry is regulated, and one powerful company might at least offer a more coherent schedule of services than the present arrangement has produced. The reason the industry was broken up into more than 100 companies at privatisation was not operational, but political: the Conservative government thought it would thus be harder to renationalise. The Economist 16.12.2000 Yes. The main conclusion is that the domination of the rail system by Virgin is not something the government should worry about.

Argument For a long time, astronomers suspected that Europa, one of Jupiter's many moons, might harbour a watery ocean beneath its ice-covered surface. They were right. Now the technique used earlier this year to demonstrate the existence of the Europan ocean has been employed to detect an ocean on another Jovian satellite, Ganymede, according to work announced at the recent American Geo-physical Union meeting in San Francisco. The Economist 16.12.2000 Not an argument.

Presenting arguments When it comes to the analysis and evaluation of an argument, it is often useful to label the premises and the conclusion, and display them on separate lines with the conclusion at the bottom : (Premise 1) If you want to find a good job, you should work hard. (Premise 2) You do want to find a good job. (Conclusion) So you should work hard. How would you write out this argument? If the Government wants to build an incinerator here they should compensate those who live in the area. Incinerators are known to cause health problems to people living nearby. These people did not choose to live there in the first place.

Validity An argument is valid if and only if there is no logically possible situation where all the premises are true and the conclusion is false at the same time. “Barbie is over 90 years old, so Barbie is over 20 years old” is valid, since there is no possible situation where Barbie can be over 90 but not over 20.

Validity & TRUTH/SOUNDness Validity is different from truth/soundness. An argument may be valid (the conclusion necessarily follows from the premises), yet the conclusion may be not true (i.e. if one or more of the premises is false). So... All pigs can fly. Anything that can fly can swim. So all pigs can swim. WORKSHEET 1 This argument is valid, but the conclusion is not true as the premise “all pigs can fly” is not true. If an argument is valid, and all the premises are true, then it is called a sound argument. WORKSHEET 2?

Is this a valid argument? P2P filesharing is a form of theft and theft is illegal, therefore one should not share files in this manner. Here we see an “is-ought gap”. The philosopher David Hume noted that you cannot have an “ought” in the conclusion of an argument without having an “ought” in the premises. Here we need another premise. What should it be? “One should not do that which is illegal” Many arguments have hidden assumptions like this, and it is usually the hidden assumption which is the most contentious!

Identify the likely hidden assumptions in these arguments: We should reduce the penalty for drunken driving, as a milder penalty would mean more convictions. + We should increase the number of convictions for drunken driving. Killing an innocent person is wrong. Therefore, abortion is wrong. + Abortion involves the killing of an innocent person. Giving students a fail grade will damage their self-confidence. Therefore, we should not fail students. + We should not damage students' self-confidence. It should not be illegal for adults to smoke pot. After all, it does not harm anyone. + Anything that does not cause harm should not be made illegal.

Inductive reasoning Inductive reasoning (as opposed to deductive reasoning) is reasoning in which the premises seek to supply strong evidence for (not absolute proof of) the truth of the conclusion. While the conclusion of a deductive argument is supposed to be certain, the truth of the conclusion of an inductive argument is supposed to be probable, based upon the evidence given. For example.... Socrates was an Ancient Greek and most Ancient Greeks ate fish. Socrates was also not a vegetarian, so Socrates ate fish.

Argument mapping An argument map is a diagram that captures the logical structure of a simple or complex argument. In the simplest possible case, we have a single premise supporting a single conclusion. Consider this argument : Life is short, and so we should seize every moment.

Argument mapping Let us now look at another example: Paris is in France, and France is in Europe. So obviously Paris is in Europe. Here is the corresponding argument map: Note that the two premises are connected together before linking to the conclusion (deductive).

Argument mapping In the following example the premises are not co-premises. They provide independent reasons for supporting the conclusion (inductively): (1) There must be life after death. (2) All religions teach that there is life after death. (3) Mediums and spiritualists can talk to the dead. (4) Many people report seeing ghosts and (5) human beings have souls and are not merely material things. Instead of writing the premises and the conclusion in full in the argument map, we can label them and write down their numbers instead: 2 3 4 5 1

Argument Sometimes, a premise leads to a conclusion which is then used as a premise to a further conclusion, and so on... (1) God knows everything. So (2) he already knows what result I will get in my Latin exam, so (4) my result in the AS examination is already fixed and so (4) there is no point me even trying to do better. 1 2 3 4

Your turn..... Can you “map” the following argument? Po cannot come to the party because (2) her scooter is broken. (3) Dipsy also cannot come because (4) he has to pick up a new hat. (5) I did not invite the other teletubbies, so (6) no teletubby will come to the party.

ANSWER (1) Po cannot come to the party because (2) her scooter is broken. (3) Dipsy also cannot come because (4) he has to pick up a new hat. (5) I did not invite the other teletubbies, so (6) no teletubby will come to the party. 2 4 1 + 3 + 5 6