PHIL1002 Lecture Notes M 5 L1 PDF

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PHIL1002 Lecture Notes M 5 L1 SUPPORT AND ACCEPTABILITY, EVALUATING A
LONG ARGUMENT and DEVISING A REDUCTIO...

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PHILOSOPHY 1002 INTRODUCTION TO CRITICAL THINKING Module 5 / Lecture 1 Argument Construction (To be read in conjunction with Govier, pp. 108–11 & pp. 246–8) Argument construction often begins with an attempt at refuting someone else’s view usually by more elaborate means than simple identification of a counter-example (see the notes Lecture 4B). One common and powerful method of refutation which involves argument construction is reductio ad absurdum. This is briefly described by Govier on pp. 248. (To understand her fully, you will need to remember some of the things pointed out at the beginning of the notes Lecture 5A.) Constructing a reductio ad absurdum Argument by reductio depends upon modus tollens and conditionalisation. The principle involved is as follows. 1. P

[prem.: provisional assumption]

2. Q

[prem.: any non-provisional assumptions, displayed as a conjunction]

3. Q & P

[2 & 1, conjunction]

4. C

[3, consequence of P and any other premisses Q]

5. If Q & P, then C

[3 & 4, conditionalisation]

6. Not-C

[obvious ex hypothesi]

7. Not-(Q & P)

[5 & 6, modus tollens]

8. Not-Q or not-P

[7, distributing the negation]

9. Not-not-Q

[2, double negation]

10. Not-P

[8 & 9, disjunctive syllogism]

‘P’ here indicates the statement which the argument is designed to refute. It appears as the first, and provisional, premiss of the argument. ‘C’ indicates any obviously false conclusion inferred from conjoining P, with some other non-provisional assumption[s], Q. The truth of Q is meant to be unquestioned and so to outweigh P when it comes to a choice between them. I have used a version of Revised Standard Form which displays more information than that set out in the notes Lecture 3A. Notice that argument by reductio carries the risk that someone who starts out by accepting P, if he admits that C is obviously false and accepts the argument as far as step 8, will move to the position that it is not after all P that is false, but rather one or more of the other assumptions which we have collected together and called ‘Q’. (That is, the proponent of the reductio offers Q as outweighing P; but the offer may be rejected.) That is, a reductio does not on its own tell us which premiss is the cause of the trouble. The argument-form sketched above uses a broad sense of ‘reductio’, where the derived consequence C has merely to be obviously false; in the narrow and more usual sense, used by Govier, C must be an explicit contradiction. An argument which leads to an explicit contradiction is more conclusive than one which leads to an ‘obviously false’ statement. This is because no one can believe an explicit contradiction, whereas people differ over whether a statement is obviously false. Argumentum ad hominem The above way of presenting argument by reductio as a strategy used against a person who holds the view (‘P’) under criticism, relates this kind of argument to another, i.e., the ad hominem (‘against the man’) argument. This can also depend upon these two moves of conditionalisation and modus tollens.

There is a powerful ad hominem argument in sections 6D–9B of Plato’s dialogue Euthyphro, where Socrates demonstrates that Euthyphro’s action in prosecuting his father for impiety is, on Euthyphro’s own account of the nature of piety, itself impious. The consequence for Euthyphro himself is that – if he cannot find an objection to Socrates’s argument, and is to be consistent, – he must either abandon the prosecution, or abandon his account of piety, or turn himself in for prosecution too. Here is another powerful example: A

. Foxhunting ought to be abolished; it is cruel to the victim and degrading to the participants.

B

. But you eat meat; and you never worry about whether the killing of the animals you eat is cruel to them and degrading to the butchers.

B’s argument, spelled out in somewhat non-standard form, goes as follows: 1. Foxhunting is cruel to victim and degrading to participants

[accepted by A]

2. Killing of animals for food is not relevantly different from foxhunting

[claim added by B]

So, 3. Both ought to be abolished

[consistent with A’s original inference]

So, 4. If 1 and 2 are true, then 3 is true

[conditionalisation]

5. But A cannot accept 3

[since A eats meat]

Hence, 6. A cannot consistently accept 1 and 2

[4 & 5, by modus tollens]

Assuming that A is moved by the requirement of consistency, this leaves him with a difficult choice of responses: A must abandon 1; or show that 2 is false; or accept 3 and (presumably) stop eating meat. Not all ad hominem arguments are as powerful as these. Here is a weaker one: You needn’t take any notice of Hegel’s views on women, because he had an unsatisfactory breast relationship with his mother and that made him funny about women all his life. But even this argument, though its degree of support is hardly strong, let alone complete, is not entirely negligible, since if its premises are true, it gives you fair warning that there is likely to be something wrong with Hegel’s views on women, even though those views, however irrationally arrived at, might be correct. Standard logic textbooks list the argumentum ad hominem as a fallacy, to be shunned at all costs. And it has to be said that such arguments never show any particular statement to be false, but instead attack something about a person. But the label in fact covers a wide variety of arguments of widely differing degrees of support. Govier’s discussion (pp. 157–60) of the argumentum ad hominem is misleadingly titled in a way which suggests that she thinks of it as always a fallacy. Reading the text reveals that she actually shares the view proclaimed here, that some ad hominem arguments are good and some are bad, just as some arguments of the modus ponens and affirming-the-consequent forms are good and some are bad. (However, her treatment of what she calls the circumstantial ad hominem treats it as always fallacious. This is to ignore the very real problems concerning consistency revealed through the Euthyphro example mentioned above. When reading p. 158, ask yourself, in the passage Govier quotes, was Lowe arguing that “Szasz’s theory is false”, as she alleges? Or was Lowe making a different point?) Criticism and construction

Whether it begins with arguments of the above forms or not, criticism is always an argumentative process, as is response to criticism, so that exercising critical skills involves constructive skills as well. The other side of this coin is that even the most purely constructive arguments will, if well-presented, always contain anticipations of the likely objections. Even if you conduct both sides yourself, an argument should always be, in effect if not in appearance, a dialogue — and the most famous philosophical arguments of all, those of Plato, are usually set out in overt dialogue form (even if the dialogues are often a bit one-sided). Govier has a good discussion of these matters on pp. 104–6. Constructing and presenting an argument Often the best place to start constructing is by formulating the conclusion you think is most probable, most defensible, most attractive, least implausible, or whatever. This needn’t be making up your mind in advance, because you’re free to change your conclusion as you go along. (You may, for instance, immediately think of a counter-example to your conclusion, which will oblige you to modify it or even abandon it.) In argument presentation, it’s nearly always a good idea to announce your conclusion at the outset, to make clear what is going on and where you are heading. Remember too that you can argue for your conclusion by denying it and trying to argue against the denial (e.g. by reductio): an argument against not-C is an argument for C. The next stage of construction is to list every reasonable and serious idea which would be relevant to proving or disproving your conclusion. This is the point at which you may need to gather data (a plural noun, whose singular is ‘datum’) from books or journals. Divide these into considerations for and against; then look for argument structures (see Lecture 3A) which will capture the relations these considerations have to the conclusion. Numbering them makes it easy to do this without constant rewriting. Choose for the presentation of your argument only those considerations which would give at least strong support to the conclusion or its denial; discard those which do least to prove or disprove the conclusion. Then assemble the remaining considerations so as to ensure clear depiction of structures. Because the direction of argument alters, ‘B, because A, so C’, is a less clear depiction than ‘A, so B, hence C’. For the same reason, don’t jumble premisses and conclusions. Those considerations which are going to figure as your premisses must be acceptable; and that means you must give thought to the kind of person your argument is supposed to be aimed at convincing. (If you are defending a theory, then such persons would be the holders of rival theories.) The presentation of an argument should always use the clearest and simplest language that is consistent with the subject matter. This may require you to define key terms if they are being used in some unusual or technical sense (though almost never if they are not). It is a commonplace that arguments should begin with the definition of terms; but this commonplace is false, and perniciously false. For example, it leads people to decorate the opening paragraphs of their work with definitions which they then proceed to ignore as they continue. (A very common fault in essays.) In any case, often definitions are more obscure than the terms being defined; and in philosophy, particularly, arguments are likely to be about what the definition ought to be, so that a definition at the outset will just beg the question. One or two well-chosen examples of its use are far better aids to clarifying the meaning of a word or phrase than most definitions. Careful consideration of the case for the opposition is an important part of argument construction; partly so that you are forearmed when it comes to facing criticism, but also so that you can learn from it (the idea is not simply to win at any cost, but to be right). Likewise, clear and sympathetic presentation of the case for the opposition is an important part of any finished and systematic deployment of argument such as an essay, so that you show that your opponent fails even on his best case. Part of this presentation must be a consideration of the most likely objections to your own argument. See Govier’s very sensible discussion of this on pp. 109–11. This does not conflict with the fact that a vital requirement for any argument is consistency. E.g., your argument will be deficient if its conclusion is supported by premisses which are mutually inconsistent. There are two importantly different ways in which statements can be inconsistent. One we have already seen: they may be contradictories, i.e., if either is true the other must be false (e.g., ‘All cats eat fish’ and ‘Not all cats eat fish’). A more subtle, and far more common, way, is for them to be contraries, i.e., they cannot both be true but may yet both be false (e.g., ‘All cats eat fish’ and ‘Some cats will eat only Smarties’). It is not inconsistent to present for consideration both sides of an argument; what is inconsistent is to do this without realising it....