Charles Saunders Peirce (1839-1914) Few persons care to study logic, because everybody conceives himself to be proficient enough in the art of reasoning already. But I observe that this satisfaction is limited to one's own ratiocination, and does not extend to that of other men. The Fixation of Belief (1877) 1. Arguments 1
The Significance of Arguments Logic deals primarily with arguments. Specifically: Their various structures and forms. The standards and procedures that can be used to understand and evaluate them. The challenge of constructing good arguments of one s own. Arguments vs. Fights In everyday speech, the word argument is often used to mean a dispute, quarrel, or fight. E.g., Fred and Wilma are constantly arguing While that use of the word is commonplace, in this course we will reserve a specific meaning for the word argument 2
Argument: Rational Persuasion Arguments do typically involve disagreement or controversy, but an argument as we will be using the term is in a sense the opposite of a fight or a quarrel. People (often) disagree about all sorts of things; arguments provide a way of resolving disagreements rationally. (In contrast to, say, using force or deception.) In other words, arguments (again, in the logician s sense of the word) aim at rational persuasion. That is, when someone puts forward an argument, she aims to persuade someone of her beliefs by means of reasons and evidence. Not all forms of persuasion are rational. Consider: (most) advertising, propaganda, the work of public relations consultants and spin doctors. 3
Sidebar: Something to Notice The use of argument to settle disputes requires that both the person offering the argument and the person to whom it is addressed already agree that they want to settle their dispute rationally (and, for that reason, will not use force or fraud just in order to get their way). That is, the real-world practice of giving and accepting reasons requires cooperation from other people they must be willing to let the better argument prevail. We will look at this phenomenon in greater detail later, in connection with audiences and relevance of premises. A Further Qualification People who study informal logic (logic that uses words, or natural language, as opposed to symbols) sometimes distinguish between logic in the broad or social sense and logic in the narrow sense. In the real (social) world, it takes (at least) two to argue; in this context, argument is about rationally persuading some other actual person or persons. As we shall see, however, an argument (in the narrow sense) need not be addressed to anyone in particular; if such an argument works, it does so by virtue of its logical form alone and it should be rationally persuasive for anyone who follows it. 4
So What Is An Argument? Consider Govier s first example: Marijuana should not be legalized. That s because sustained use of marijuana worsens a person s memory, and nothing that adversely affects one s mental abilities should be legalized. Conclusion (the claim being made): Marijuana should not be legalized. Premises (the reasons for the claim): 1) marijuana adversely affects memory and 2) nothing that adversely affects mental abilities ought to be made legal available. How that works The premises of this argument may or may not be true; you may agree or disagree with the premises and/or with the conclusion. The argument as a whole, however, invites you to see the connection between the premises and the conclusion, such that, if you accept the premises, then you should accept the conclusion that follows from them. 5
Another Argument Any government that caves in to terrorists must be suffering from a lack of conviction. We know that the US government has already implemented a policy of never giving in to terrorists. So the US government clearly doesn t suffer from a lack of conviction. Conclusion:? Premises:? And Another If the mall was open, the parking lot would not be empty. But the parking lot is empty. So the mall must be closed. Conclusion:? Premises:? 6
A General Model of Arguments Premise 1 Premise 2 Premise 3 Premise n Therefore, Conclusion Opinion Earlier we said that the premises of an argument may or may not be true. (Later on, crazy as it may sound now, we will learn that an argument may be valid, though not sound, even when it premises are false). In real life, however, premises do not come clearly sorted into true and false. In some cases, we may have very good reasons to believe that some premise is true. In other cases (e.g., in mathematics) we may be able to see that a certain premise is necessarily true (i.e., it could not be otherwise). Often, however, we are to some degree uncertain about the truth of our beliefs 7
Opinion, says Govier, is a belief held with a relatively low degree of confidence. We may have some reason to believe that our opinions are true or well-confirmed, but, in many areas, we may never be certain about the truth of our opinions. (Notice that certainty is a very high standard, one that is not met even by most scientific knowledge.) A traditional contrast: (Mere) opinion vs. (hard) facts. But facts, often, are simply opinions held with a relatively high degree of confidence. Opinions and Credibility: An Example Is pesticide X is harmful to the environment? Different parties may offer different opinions. (e.g., ecologists, focused on the health of ecosystems may have one view, biotech companies, focused on profits and avoiding regulatory hassles may have another). What the different parties can t deny, if they are committed to rational persuasion, is that reasons and evidence are relevant to deciding this question one or the other. 8
But I have right to my own opinion! We hear this all the time and, as a matter of legal and political rights, it is certainly true. Each of us is entitled to hold and to express (nearly) any opinion that we want and no one can coerce us into believing something that we do not in fact believe. This does not mean that all opinions should be accorded equal respect, however. Some opinions are mere opinions, carelessly formulated or based on bad or insufficient evidence. So, once again, it is legally and politically permissible for each of us to hold tenaciously to any beliefs we choose. But such tenacity is not, so to speak, logically permissible. Nor is it a good way to go through life: Our beliefs necessarily guide our actions and, when it comes to making practical decisions, we will be better off if we form (and re-form) our beliefs on the basis of accurate evidence and well-founded, coherent reasons. 9
Identifying Arguments Consider the following (fairly strong, though incomplete) single-premise argument from the philosopher René Descartes: I think, therefore, I am (i.e., I exist). In this argument, the word therefore signals the conclusion of the argument. Another Example Consider the following (rather weak) singlepremise argument: The Flames will likely win the Stanley Cup this year, since Darryl Sutter is such an awesome coach. In this argument, the word since introduces the premise. 10
Indicator Words Words like therefore and since are termed indicator words they indicate the presence of an argument, premise or inference. Some indicator words: since because for give that as indicated by as shown by may be inferred from may be derived from on the grounds that for the reason that may be deduced from follows from In abstract, formal terms, we say that a person argues from her premises to her conclusion. As we have already seen, however, an arguer may not necessarily present her premises first and then present her conclusion. For reasons of style or convenience an arguer may present the argument A, therefore B in the form B, since A 11
In identifying arguments (and, later, in translating arguments into categorical or propositional form), it will be useful to pay attention to indicator words, since they help us to follow the direction of arguments. Especially useful are those indicator words that typically signal a conclusion. Appropriately enough, Govier calls these conclusion indicators. Some Conclusion Indicators therefore so hence it follows that in conclusion for this reason proves that indicates that demonstrates that thus consequently then it can be inferred that accordingly on these grounds shows that we can conclude that we can infer that 12
A Bit of Practice 1. All the senior managers here are members of the owner s family. So I ll have to move if I want to get promoted. 2. A human being is constituted of both a mind and a body. But the body does not survive death. Thus we cannot properly talk about personal immortality. 3. Gary must be a member of the Metallica Fan Club, because he was at the meeting last week and only members were admitted. Sidebar: Need arguments use any words at all? As we ll see later on, arguments can be expressed in symbols that need not stand for any particular words. So, in that sense, no. More interesting, however, is the question of whether arguments can be expressed in forms that use neither words or symbols. Consider 13
British Army Recruiting Poster, 1914, featuring Lord Kitchener British Army Recruiting Poster, 1997, featuring a solider of African decent. 14
Team logo of the University of Northern Colorado intramural basketball term, The Fightin Whities. Why Are Arguments Important? Not every assertion needs an argument to support it. E.g., if a political commentator points out that the US Presidential election will take on November 2 nd, there is no need for her to supply an argument to back this up. The date of the election is prescribed by US law and takes place every four years on the same date. 15
But arguments, where they are needed, are crucially important. As Govier says (9): unlike descriptions jokes, stories, exclamations, questions, and explanations, arguments are attempts to justify claims. That is, in offering an argument we are seeking to provide others with reasons to adopt our beliefs and/or to guide their actions in some way. This is serious business. Attempting to justify our beliefs is important for both practical and theoretical reasons (10). Good reasoning leads to good decisions in guiding our actions and choices. Careful, reflective reasoning about what we believe can help to assure us that what believe is actually true (or at least supported by good reasons and evidence) 16
What Isn t an Argument? Not every statement offers or is part of an argument. Some statements simply express emotions: I hate broccoli Others ask questions or simply state (uncontroversial) facts: Which way to the washrooms? Thirty-six divided by six equals six. Sometimes, it is a matter of interpretation whether or not some text does or does not contain an argument. (See the Greenpeace passage, p. 12) 17
Arguments vs. Explanations Govier asserts that explanations are not arguments, since explanations are geared toward understanding rather than persuasion. This is a somewhat tricky point and not all logicians would necessarily agree. We might say, e.g., that an explanation is always implicitly an argument or could easily be transformed into one If you turn right at the gas station, you ll see the MacDonald s on your left is an explanation of how to get to the restaurant. But consider: [I assert that] if you turn right at the gas station, [it is true that] you will see the MacDonald s on your left. This has at least the appearance of an argument. 18
More on Arguments vs. Explanations What is definitely true is that an explanation is different from an argument with respect to the intentions of the person who is offering it. This is especially clear in cases where someone is explaining beliefs that they do not themselves hold: According to so-called White Supremacists, we have all been brain-washed by the liberal media into thinking that the Jews cannot be held responsible for the mongrelization of the white race. This is a partial explanation of why some other people hold the beliefs that they hold; the speaker is not asserting that those views are true. What can make the distinction especially tricky is that, as Govier notes, explanations typically use the same sort of indicator words that arguments do. Govier s suggestion for keeping these things clear: Arguments offer justifications; explanations offer understanding. 19