In this chapter we analyse and evaluate an argument by a famous philosopher, A. J. Ayer, about the connection between (i) electrical impulses in our brains and (ii) thoughts and ideas in our minds. Most of us have a reasonably clear idea about what we mean when we talk about ‘thoughts and ideas in our mind’ and we know that scientists study how the brain works, how it is constructed, how ‘messages’ are transmitted within it and so on, but Ayer's piece is about the connection, if any, between the two – about how one's brain and mind interact with each other.

If you conjure up an image of an elephant in your mind's eye, or entertain the thought that ‘the moon has a weak gravitational field’ or decide to raise your arm, you might expect some ‘corresponding’ activity in your brain – some activity (physical, chemical, electrical or whatever) of a kind that scientists could see, describe and study. But what is the connection between the two? Does one cause the other? Does the ‘mental activity’ of deciding to raise your arm somehow send signals to your muscles which cause your arm to raise and, conversely, do electrical impulses in your brain somehow cause you to have the image of an elephant in your mind's eye or to entertain the thought about the moon's gravitational field? Alternatively, do these two distinct kinds of activities – the mental and the physical – just occur together without causally interacting?

The following passages are provided so that the reader can try out the approach of this book to see if it is helpful. The exercise in each case is the same: it is to extract the argument and to evaluate it using the methods and principles explained in the preceding pages. The author's experience is that students have difficulty in being clear-headed about these and similar (theoretical and argumentative), passages, but that the methods expounded earlier are a genuine help. The teacher will no doubt wish to supply further exercises which are particularly suited to his or her students: the following examples are provided only as a starting point.

An argument is considered in Chapter 1 which relates to this exercise (see p. 13). The Campaign for Nuclear Disarmament (CND) campaigns for unilateral nuclear disarmament for Britain. It does so on various grounds and the ‘nuclear winter’ evidence has been used widely by CND in support of its campaign. However, the following appeared in the Eastern Daily Press newspaper in October 1984. A similar position was taken by some prominent politicians.

Now that we have shown how in general to handle suppositions, we have explained how to extract arguments from their context and how to represent their structure in sufficient detail for us to be able to delve more deeply into the third part of the exercise – evaluating the soundness of an argument – for a wide range of important arguments.

Remember that in order to test whether an argument is sound we have to ask,

and in order to establish the appropriate standards we ask the Assertibility Question,

Remember furthermore that, as we have insisted from the beginning, anyone can ‘play this game’: it is not just a matter for the ‘experts’.

Two initial examples

Suppose we encounter the claim that ‘like magnetic poles always repel’ (M). What would show that this was true or false (allowing this as a paraphrase of the Assertibility Question)? If you understand the meaning of the claim M you must be able to give some kind of answer to the question (remember principle * p. 23).

In this chapter we apply the method we have outlined so far to a real and quite complicated example due to Karl Marx. The reader should first read the passage through and should then attempt to answer the questions which immediately follow it. Unless one does this it is easy to underestimate the difficulties in Marx's argument.

Those readers who can answer the questions without recourse to the method we have outlined need read no further, but we hope that others will find that the method enables them to answer questions which otherwise defeated them.

Karl Marx: Value, Price and Profit

Karl Marx was born in 1818, the son of a lawyer. He studied at the universities of Bonn and Berlin before embarking on a life of journalism and political activism. He was expelled from Prussia in 1849 having been acquitted of high treason. He settled in London where he spent the rest of his life, often in real poverty. He died in 1883 and is buried in Highgate cemetery in North London.

His major work, Das Kapital, makes very hard reading, but our extract comes from his Value, Price and Profit, which gives a much simpler statement of his ideas. It was originally delivered as a paper to an international congress of working men in 1865. At that time there was ‘on the continent a real epidemic of strikes, and a general clamour for a rise of wages’, as Marx put it, and the question was whether working people could increase their wages by such activity.

This second edition differs from the first mainly by the addition of two new chapters. These deal with some fascinating arguments about the existence of God and about how our minds and bodies interact. Although this approach to teaching students how to analyse and evaluate arguments was first published in 1988, many students and teachers still find it useful and instructive, and this seems to be especially true in Philosophy departments, hence the choice of new topics. The general approach has not been changed here, but the new examples illustrate applications of my approach in particular contexts – some especially philosophical and one which is rhetorically powerful. It has been a pleasure to write this second edition and I particularly want to thank Nicholas Everitt for reading the new chapters and making very helpful suggestions; I often accepted these but, needless to say, the resulting work is my responsibility. Again I also wish to thank Cambridge University Press for their help and patience and my wife and family for theirs too.

The method of argument analysis which is developed in this book is distinctive in employing the Assertibility Question. We introduced it in Chapter 2, we explained how to use it and we have illustrated how it works in several examples, but since it underlies our whole approach we must now attempt to answer some questions which may be raised about it. We shall first remind ourselves of our objectives and of how the Assertibility Question functions in attempting to realise those. We shall then explain some ideas about meaning which lie behind our method. We then provide a brief reply to the general challenge of scepticism and finally we explain why we attach relatively little importance to the notion of deductive validity in this whole exercise.

Objectives

Our objective is to describe and demonstrate a systematic method for extracting an argument from its written context and for evaluating it. We want a method which will apply to a wide range of both everyday and theoretical arguments and which will work for ordinary reasoning as expressed in natural language (and not just for those made-up examples with which logicians usually deal). We also want a method which draws on the insights and lessons of classical logic where these are helpful, but which is non-formal and reasonably efficient (both requirements exclude a method which requires us to translate real arguments into the symbolism of classical logic).

In this chapter we consider a classic ‘nugget’ of an argument due to John Stuart Mill (1806–75). It comes from his Principles of Political Economy which was first published in 1848 and which ran to seven editions in his own lifetime.

James Mill, John Stuart Mill's father, and his friend Jeremy Bentham founded and promulgated the philosophy of ‘utilitarianism’ which was based on the doctrine that actions are good in so far as they ‘promote the greatest happiness of the greatest number’. James Mill was a highly educated man in many spheres and he took sole charge of his son's education from the beginning. He began to teach his son Greek at the age of three. They sat at the same table at which his father worked and, since there were no such things as English-Greek dictionaries,

In this chapter we show how to analyse and evaluate a very famous argument due to Thomas Malthus (1766–1834) and we apply and develop the method of Chapter 2 in the process. Malthus's father was a friend of David Hume and of Jean-Jacques Rousseau, both of whom visited his house together when Thomas was only three weeks old. It was under the influence of Rousseau's Emile that his father had Thomas privately educated until he became an undergraduate at Jesus College, Cambridge, at the age of eighteen, in 1784. He graduated well in mathematics in 1788, and he took Holy Orders in the same year. His Essay on the Principle of Population as it affects the Future Improvement of Society with Remarks on the Speculations of Mr. Godwin, M. Condorcet and other Writers was first published in 1798. There was much discussion at that time – in the wake of the French Revolution – about the possibility of establishing a society based on social and economic equality. Malthus's Essay originated as a polemic against such utopian speculations. His argument was not new,

Does God exist? There are many fascinating arguments which relate to this subject and in this chapter we look at just two. We do this partly to give more examples which use our method of analysing and evaluating arguments, but also to see how the method copes with two distinctive kinds of argument – one rhetorical and one philosophical. We begin with a piece by Richard Dawkins called ‘The more you understand evolution, the more you move towards atheism’ and then we look at a piece by A. J. Ayer.

SECTION A: DAWKINS

Dawkins: ‘The more you understand evolution, the more you move towards atheism’

Dr Richard Dawkins is Professor of Public Understanding of Science at Oxford University. He is famous worldwide for his work in biology, especially as he explains it in a number of very readable books including The Selfish Gene, The Blind Watchmaker, River Out of Eden and several others. The following piece is an edited version of a speech he made at the Edinburgh International Science Festival on 15 April 1992. It is reprinted from the Independent newspaper with the permission of Dr Dawkins (paragraphs are labelled for ease of subsequent reference).

1. (a) As a Darwinian, something strikes me when I look at religion. Religion shows a pattern of heredity which I think is similar to genetic heredity. The vast majority of people have an allegiance to one particular religion. There are hundreds of different religious sects, and every religious person is loyal to just one of these.

2. […]

The arguments we consider in this chapter are about nuclear deterrence. This is a subject in which reasoning plays an enormously important part. Deciding which is the best policy is not simply a matter of discovering the facts about the weapons systems available to the two sides because it is hard to tell what these facts imply about intentions under deterrence, nor is it simply a matter of resolving to defend oneself since the difference between defensive and aggressive acts is obscure under deterrence. The importance of the arguments cannot be disputed, so how should we resolve them?

This chapter attempts to contribute to the debate not directly, but by explaining a method of analysing arguments using two specimen texts from the very extensive literature on the subject. The texts we have chosen are quite typical: there are certainly many other pieces expressing similar arguments and no doubt many of these would have served our purpose equally well; however, our focus of interest is not on these particular texts (typical or not) but in the method of assessing them. We succeed in our objective if the reader grasps the method of analysis explained by reference to these examples and is then able to apply it to other pieces of reasoning.

This book arose out of my experience of teaching logic. Like many others I hoped that teaching logic would help my students to argue better and more logically. Like many others, I was disappointed. Students who were well able to master the techniques of logic seemed to find that these were of very little help in handling real arguments. The tools of classical logic – formalisation, truth-tables, Venn diagrams, semantic tableaux, etc. – just didn't seem to apply in any straightforward way to the reasoning which students had to read in courses other than logic. At the same time I felt that it ought to be possible to give students some guidance – some procedure – which would help them to extract and to evaluate arguments from written texts and which would help them to write good arguments of their own. I wanted the procedure to be non-formal but to build upon the insights of traditional logic; this book attempts to realise that objective.

Many other teachers of logic and philosophy have had much the same experience in the past two decades and the result has been the emergence of what is now called the ‘informal logic and critical thinking movement’ in North America. One of the first books in this tradition was Monroe Beardsley's Practical Logic, a book which is still well worth reading over thirty years on. Stephen Toulmin's The Uses of Argument is another classic attempt at providing an alternative framework for understanding reasoning.

In Chapter 1 we considered several examples; most of them were arguing a case and we used them to point up various lessons about reasoning. Having given the reader a taste of argument analysis we now introduce a general method for analysing and evaluating arguments. The method lay behind what was said in Chapter 1 but the reader who tried the exercises should now be ready for a general account rather than the piecemeal approach.

The method which we describe applies to reasoning, or argument, as it actually occurs in natural language – in our case, English. We begin by describing how to recognise contexts in which reasoning is taking place (i.e. we say what the ‘linguistic clues’ are). We then describe how to uncover and display the structure of a piece of reasoning (whether it is a ‘chain’ of reasons etc.). Finally we explain, as far as possible, how to decide whether the reasoning is correct or incorrect.

At this stage we do no more than outline the method. We do this so that its essential lines may be boldly drawn and clearly grasped. Too many qualifications at this point might obscure the method's basic simplicity: if it is basically correct the place to develop and refine it is where the problems arise – in applying it to particular examples – and this is what we shall do. In subsequent chapters the basic skeleton will be extended and ‘fleshed out’ as the need arises.