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In Praise of Scepticism

Updated: Feb 19, 2021

Michael Inwood is Emeritus Fellow at Trinity College, University of Oxford. He read Classics at University College, Oxford, before his appointment as a philosophy fellow at Trinity in 1967. Professor Inwood taught at the John Locke Institute summer school in 2015.

In ordinary conversation, a philosophical approach to life is often regarded as having a calm and resigned attitude to it, especially to its difficulties. Philosophy is calm resignation.

But that isn't how teachers of philosophy, like myself, regard it. When we are introducing pupils to the subject, we ask them questions that are meant to unsettle their ordinary beliefs and arouse unease and doubt in their minds. We ask such questions as: How do you know that you are really having an interview? How do you know that you're not having a nasty dream? What makes you so sure that I am a real person and not a cleverly devised robot? Why don't you leave my room by jumping out of the window? It's much quicker than walking down the stairs and you can't really be sure that you'd come to any harm, can you? If a pupil says that he or she believes in God, I ask them why. And if they say they don't believe in God, I ask them: why not?

From the very beginnings of philosophy, in ancient Greece, scepticism - the challenge to a person's everyday beliefs - has been an important stimulus to philosophy. It begins with scepticism about morality. In Greece, as in all the societies we know of, there was a strong taboo on incest, on marriage and sexual relations between close relatives. Most people just take it for granted that incest is wrong and do not ask why. But philosophers did not take it for granted and did ask why. They noticed, or thought they noticed, that whereas in Greece men could not marry their sisters, in Egypt they did. What was morally wrong in Greece was apparently not morally wrong in Egypt.

There are several different responses we might make to this dilemma. First, we might argue that one side in the dispute is right and the other is just mistaken. We might argue, for example, that the Greeks were right and the Egyptians were mistaken. But how do we show that? That is where philosophy gets going in earnest. We have to argue for beliefs that are ordinarily taken for granted and accepted uncritically. As a matter of interest, one Greek philosopher, Carneades, argued in favour of incest and also of cannibalism. Another response is to say that moral rightness and wrongness are relative matters. That the Greeks and the Egyptians are both right. Incest is wrong for Greeks and not wrong for Egyptians. Cannibalism is ok for cannibals but wrong in Oxford. But that response too is unsettling. We tend to feel that some things that we regard as wrong are really wrong, full-stop, and not just wrong for us. Morality is not the same as etiquette. It doesn’t depend on where you happen to live.

One of the greatest of philosophers, Plato, was also inspired by moral scepticism. He did not accept it but tried to overcome it. But for the moment I'll concentrate on the scepticism rather than on attempts to overcome it.

He told the story of a man, Gyges, who caught a fish in which he found a ring. When he put the ring on his finger, he discovered that it made him invisible. He decided to use this gift to his own advantage and he went into the king's palace, murdered the king, married the queen and made himself king instead. Plato, of course, thinks he shouldn’t have done this, and so do we. But why do we believe this? What reason did Gyges have for acting otherwise, if he served his own best interests by doing what he did? When I taught Plato's Republic to students I often asked them what they would do if they had a ring like Gyges's. Most of them were not as ambitious as Gyges and said that they would do nothing more than sneak into the girls' changing rooms or try to find out the questions on their examination papers in advance. What would you do if you had such a ring?

One of the techniques that philosophers often use in order to express their scepticism is to ask you what you mean by some word that you use. If you use a word such as 'dialectical' or 'imperialism', or even 'philosophy', in an interview, the chances are that the interviewer will ask you what you mean by it. This is very disconcerting, because unless you consulted a dictionary before the interview, you are unlikely to have a ready reply, and when you come to think about it, you find that you don’t have any clear idea of what you did mean. Plato's teacher, Socrates, often uses this technique in the dialogues that Plato wrote about him. If someone says to Socrates that he teaches, say, virtue, Socrates asks him what he means by virtue or what is virtue, and when the other gives some reply to this question, Socrates goes on to show that what he has said is open to various objections.

One interesting example of this technique occurs in a dialogue called the Euthyphro. Socrates has met a young man, Euthyphro, who says that he is on his way to court in order to prosecute his own father because his father has killed one of his own servants. Socrates asks him why he is taking this unusual step and Euthyphro replies that he is doing it because it is pious or holy. Socrates asks him what piety is, and Euthyphro says that it is doing what the gods want. We might have asked Euthyphro how he knows that there are any gods and, if there are, how he knows what they want. But Socrates asks a more interesting question: Do the gods want you to do things because they really are holy or is it rather that things are holy just because the gods want you to do them?

Whichever answer Euthyphro gives, he is in difficulties. If he says that the gods want us to do things because they really are holy, Socrates can say that we can then find out for ourselves what is holy and do not need to bring the gods into it at all. If Euthyphro takes the other route and says that things are holy because the gods want them, that the gods make things holy just by wanting them, then Socrates will ask why we should do what the gods want, if they have no good reason for wanting them in the first place. This has come to be known as the Euthyphro Dilemma, and it applies not only to the Greek gods but also to the Christian God. If someone is asked: 'Why should you pay your debts and taxes?' and replies 'Because God commands it', we can go on to ask: 'Does God command it because it is really right? Or is it right just because God commands it?' Then if the answer is that God commands it because it is right, then it seems as if we don't need God's command as a reason for doing it, but can find out what to do on our own. If the answer is that God makes it right just by commanding it, we can ask: 'So why should we obey God's arbitrary commands?' This shows that there is a difficulty in appealing to God as a support for morality.

The difficulty is not necessarily insuperable and many replies have been given to it. But it gives me my cue for leaving God or gods out at this point and returning to the general question of scepticism. For something like the Euthyphro dilemma crops up in other areas where doubt and scepticism lie in wait for us.

Let me take a simple example first. Do we laugh at jokes because they really are funny, or are jokes funny just because we laugh at them? God doesn’t come into this because we can't plausibly suppose that God laughs at our jokes. He's heard them all before, and if he has a sense of humour it must be far more sophisticated than ours. Here it doesn't matter very much if we are sceptical about the objectivity of funniness because we don’t regard humour as very important. It is, of course, an important feature of our lives, but it is rather like etiquette in that it varies greatly at different times and different places. So I'm inclined to say that a joke is funny just because it makes us laugh and not the other way round: we don’t laugh at things because they are objectively funny because nothing is objectively funny. I say that a joke is funny because it makes us laugh, and not simply because it makes me laugh or some other particular person laugh, since there are of course standards of funniness within a society or within a social group, as there are in the case of etiquette. Someone who laughs uproariously when a man slips on a banana skin is out of place in our society. If anything is funny about this situation, it's the person laughing.

Now I come back to what I began with: scepticism about morality.

I've already raised a sceptical doubt about morality by starting with humour and funniness because in some respects morality and right and wrong are rather like humour and funniness. And, as I suggested, it is really quite plausible to think that whether something is funny or not is not an objective matter, but depends only on what makes us laugh. Is it the same with morality? Does it depend on nothing more than our likes and dislikes? However, although morality and humour are similar in some respects, there are also important differences. Morality, people's moral views, do vary over time and place, but not nearly so much as humour does. In virtually every society theft, assault and murder are forbidden, except in special circumstances. Again, an immoral person is often far more of a nuisance than a person with no sense of humour. So we are in this case far less inclined to say that thinking something is right makes it right and that thinking something is wrong is what makes it wrong. We not only think that cannibalism in Oxford is wrong, however convinced the cannibal may be that he is in the right. We also think that cannibalism is wrong in societies where it is an established practice and that such other societies, if there are any, should be converted to our morality.

"Philosophy begins with sceptical doubt."

But philosophers have given several reasons for believing that at bottom morality is no more objective than humour. One reason given is the scientific view of the world that we accept. That seems to leave no room for values. It has to leave room for human beings who believe in values – they obviously exist – but not for the values themselves. Another reason given is that there is an unbridgeable gulf between facts and values. A person who says: 'So what if he's human? I agree that that is a fact. But why does it follow that I shouldn’t eat him?' or 'So what if I've borrowed money? Is that any reason why I should pay it back?' seems to have committed no logical error. Of course, we have good reasons to make our fellow citizens conform to our moral standards, but those might be reasons of convenience rather than of ultimate morality. It might be rather like the way in which we make, or encourage, everyone in England speak English, even though we do not believe that English is intrinsically superior to other languages, such as French.

So far we've been assuming that we all know certain facts. We know that people laugh and that sometimes they trip on banana skins. We know that someone borrowed money, even if we don’t know that he should pay it back. And we know that the modern scientific view of the world is more or less correct. But how do we know all that? Do we really know it at all? Philosophers such as David Hume and Rene Descartes have come up with various ingenious arguments to undermine our confidence in our everyday beliefs. Let me run through some of them:

In the past, I’ve made mistakes. I thought a stick in water was bent, but it turned out to be straight. I thought I saw a policeman outside Madame Tussauds, but it turned out to be a waxwork. I thought a tower was round when I saw it from a distance, but on closer inspection, it turned out to be square. I thought I was sailing in the Mediterranean, but it turned out that I was only dreaming.

This happens on a larger scale too. A few centuries back, most Europeans, including some highly intelligent and honest Europeans, believed that there were witches. Now we no longer believe that and we are puzzled as to how anyone could believe such a thing. But how do we know that our beliefs now are not similarly mistaken? And how do I know that I am not mistaken now in thinking that I am typing out an article for the John Locke Institute? I might, after all, simply be dreaming. How can I be sure that I am not? You might think that we could find some criterion for testing whether our beliefs are true or not. But that obviously begs the question. How can we be sure that we have found the right criterion or that we have applied it correctly? To take a simple example, people are often said to pinch themselves to make sure that they are not dreaming. But that doesn't work because I can dream that I am pinching myself as easily as I can dream about anything else.

Here's another problem, one that we owe to David Hume. This is the problem of induction. Why doesn’t the student leave my room by jumping out of the window, as I suggested? It is because he or she knows that, in the past, objects that have fallen to the ground from a great height have invariably been damaged by the collision. Why do we believe that the sun will rise tomorrow or that the water in a kettle will boil at 100 degrees? It is because in our experience the sun always has risen every day and water always boiled at 100 degrees. But it is quite conceivable that tomorrow the sun will not rise and that water will boil at 10 degrees. What makes us so sure that that won't happen?

In fact, induction doesn't always work. Bertrand Russell tells a story about some chickens in a henhouse. Every day in their experience the farmer has come to feed them. So they expect that when he comes today he will feed them again. But he wrings their necks instead. In some respects, we are like Russell's chickens. Every day in my experience I have woken up in the morning. But one day I won't. But we don’t usually think that we are like them in every respect. We are fairly convinced that the sun will go on rising for many years yet and that water will continue to boil at 100 degrees. But how can we be sure?

Another problem that undermines our confidence in what we think we know is when we come across another person, or another culture, that has different beliefs from ourselves. The ancient Greeks noticed this problem. Suppose I am firmly convinced that God doesn't exist. Then I come across someone else who is equally firmly convinced that God does exist. Or on a larger scale, they noticed, as I said before, that the Egyptians believed that marriage between a brother and a

sister was legitimate, whereas the Greeks did not.

This is a matter of morality, but the problem arises for knowledge in general.

We believe that diseases are caused by such things as bacteria and viruses. But suppose there are tribes that believe they are caused by witches. How can we persuade the other tribe or the other person that we are right and they are wrong? We can give a reason for our belief. But then the other tribe or person can give a reason for their belief. Then we give another reason for our second belief. But of course, the other tribe can give a reason for their second belief. The argument could go on forever like this if the people arguing were ingenious enough.

Or perhaps we reach rock bottom beliefs, beliefs for which no further reason can be given. Providentially, we generally find that there are rock-bottom beliefs on which people agree. But occasionally they might slip in a belief that they claim to be absolutely convinced of, but which doesn't appeal to us – not at least without further argument. An American philosopher, Alvin Plantinga, has said that one of his rock bottom beliefs is his belief that God exists. He is more certain of the existence of God than he is of his own existence. He could not be more certain of anything than he is of the existence of God. This is disturbing, I think; we usually regard the question of God's existence, or non-existence, as something to be argued for from our other beliefs and not as a rock bottom belief. But it is difficult to dispute Plantinga's claim and it leaves open the possibility that another tribe should claim that their belief in witchcraft is a rock bottom belief. If they do, it looks as if all argument comes to an end and there is nothing we can do to settle the dispute.

The point of scepticism is to make us think about the justification and limits of beliefs.

I shouldn't leave the subject of knowledge without mentioning the brain in a vat. This is an updated version of a problem posed by Descartes in the 17th century. As well as wondering how I know I'm not dreaming, Descartes also asked how I know that all my experience is not a delusion produced in me by a malign genie, an evil demon. The more recent version of this asks: How do you know that you are not a brain in a vat, manipulated by clever scientists to give you exactly the experience you have, only all of it illusory? You can't give any reason or evidence that you are not just a brain in a vat, because whether you are a brain in a vat or not, your experience will be exactly the same. So you don’t know that you are not a brain in a vat. And so, the argument continues, you don’t know much else either. You don’t know that you are reading the John Locke website, for example. That may be just one of the illusions these scientists are producing in you.

Ok, so that's enough scepticism for the time being.

Now I should add that most philosophers are not as sceptical as I might have made it sound. They usually leave a room through the door. They do not jump out of windows. Hardly any of them believe that they are dreaming. And I have never met anyone who seriously believes that he is a brain in a vat. So why do they continually propose these sceptical problems? One answer is that they do so in order to make us think. They do so in order to make us search for a solution to the problems they pose. Or to make us ask: why am I so sure that I am not dreaming, not a brain in a vat, and so on? Their answers are generally too complex for me to explain here, but you can take my word for it that the raising of sceptical problems and the attempt to find an answer to them has given rise to much fine philosophy.

Instead, I want to draw a distinction between different types of scepticism.

On the one hand, there is make-believe philosophical scepticism about things that (almost) no one in their right mind seriously doubts; I mean such things as the existence of the external world, the existence of other people on a par with myself, the legitimacy of relying on past experience to form expectations about future events, and so on. The point of this scepticism is, as I've said, to make us think about the justification and limits of such beliefs, not to get us to abandon the beliefs.

On the other hand, there are some beliefs that we hold that we probably ought to be sceptical about, or at least more sceptical than we usually are. I mean, for example, that people often have political beliefs – that this political party or this political policy is better than the other one. Now these beliefs are usually pretty dubious, both because there is widespread disagreement about them and because we are so often disappointed by the performance of our preferred party or by the effects of our preferred policy. I am not claiming, of course, that no one should hold any such beliefs; that would be disastrous if it meant that no one bothered to vote in elections, because then we would either have to find some other way of forming a stable government or we would have no stable government at all. So what one should probably do is stick with your beliefs, but regard them with a sceptical eye.

Or, to take another example, many people have religious beliefs, whether loose and vague or intense and definite. These are as dubious and uncertain as political beliefs, though they are not so

exposed to definitive refutation as political beliefs. Philosophers since the Enlightenment and even before that have of course challenged the legitimacy of religious beliefs, though there are still some who retain them. (Alvin Plantinga, whom I mentioned earlier, is a philosopher of great distinction and also a devout Christian.) What I would suggest is that philosophy does not require that we abandon such religious beliefs as we have, any more than it requires us to abandon our political beliefs, but that it does require us to keep a sceptical eye on our beliefs.

What this involves is, first, that we take account of the arguments against our beliefs as well as the arguments in favour of them; and, secondly, that we maintain a respectful tolerance of people who have different beliefs from ourselves. These are connected: if I take account of the arguments against my own beliefs, then I automatically have some appreciation of other people's reasons for holding different beliefs. I have the ability to look at matters from the other person's point of view, and to consider things from various perspectives.

Let me now sum up what I have said. Philosophy begins with sceptical doubt. The matters that philosophers doubt lie on a spectrum. At one end lie matters that no one seriously doubts, such as the existence of the external world, where the point of the doubt is to provoke thought about the meaning and justification of the belief. At the other end of the spectrum lie matters about which it is reasonable to have doubts, such as political and religious beliefs and, of course, other fashionable beliefs that change every 40 years or so. It doesn't follow that we should abandon such beliefs. We can't get by without beliefs even about such dubious matters. But we should bear in mind the case against them as well as the case in their favour.

Philosophers tend, as I've said, to be sceptical creatures and so we are also sceptical about what other philosophers say. Hence philosophers tend to disagree with each other more than do the members of most other professions. You are therefore very welcome to express your disagreement with what I have said.

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Waters Charlie
Waters Charlie
4 days ago

When Michael Inwood spoke at Oxford University on St. Thomas Aquinas's philosophy, I would go to his classes. Oxford was a very different place fifty-five years ago this year when he started teaching at Trinity College. I was delighted to have him as a guest at our summer school in 2015 because of the profound impact he has had on generations of students at Oxford. geometry dash


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Martin Cox
Martin Cox
Feb 20, 2021

I used to attend Michael Inwood's Oxford University lectures on the philosophy of St Thomas Aquinas. He began teaching at Trinity College, Oxford, fifty-five years ago this year, when Oxford was a very different place. He has left a deep impression on generations of Oxford students, and I was thrilled to welcome him to our summer school in 2015.

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