Most recent common ancestor

There has been a pause in my blogging. I have been engrossed in other work. The pause may last for a while longer. So here is a little puzzle, as an entr'acte.

According to Wikipedia, Elizabeth of York, wife of Henry VII, is the most recent common ancestor of all English monarchs. I have not checked this claim, but let us assume that it is correct. The puzzle, which we would need to solve before checking the correctness of the claim, is as follows.

How should we define "most recent common ancestor" in this context, so that a determinate person, or a determinate couple, is picked out, and so that it is interesting that this person, or this couple, is picked out?

The condition of interest would be failed if our definition led us to pick out George VI, or even if it led us to pick out George V, or Victoria. We want some sense of "furthest back most recent". But then, we must not allow Elizabeth of York's mother, Elizabeth Woodville, to displace her.

Technical terms from mathematics may be used freely.

Blogspot does not, so far as I know, support LaTeX math environment, so please feel free either to cut and paste logical symbols from elsewhere, or to use E for the existential quantifier, V for the universal quantifier, - for negation, and > for implication.

Bonn, Berlin and Gettier

This month, we are fifty years on from the publication of Edmund Gettier's celebrated paper, "Is Justified True Belief Knowledge?" (Analysis, volume 23, number 6, June 1963, pages 121-123). Today, 17 June, is the sixtieth anniversary of the uprising in East Germany, which might have led to the early reunification of Germany (at least according to a broadcast on B5 radio this morning), had the Soviets not sent the tanks in.

We may also recall, for no particular calendrical reason, Bertrand Russell's note of the Gettier phenomenon, avant la lettre. The story is told in J E Littlewood, Littlewood's Miscellany, edited by Béla Bollobás, 1986, page 128. "He told me (c.1911) that he had conceived a theory that 'knowledge' was 'belief' in something which was 'true'. But he met a man who believed that the Prime Minister's name began with a B. So it did, but it was Bannerman and not Balfour as the man had supposed." [Balfour was Prime Minister from 1902 to 1905, and Bannerman from 1905 to 1908.]

Let us stick with the letter B, but move forward to the present day. Suppose that Claude, who has never lived in Germany, and whose access to German news is very limited, was taught in school, in the 1970s, that Bonn was the capital of West Germany, that West Germany was much larger, and much more significant economically, that East Germany, and that one part of Berlin was the capital of East Germany. Since then, Claude has heard of German reunification, but not of any change of capital. He reasons that the capital of Germany is probably still Bonn, but that it might have been moved somewhere else, and that if it had been moved, Berlin would have been the most likely choice.

He therefore forms the justified true belief that the name of the capital of Germany begins with a B. Does he know this?

The case is not on all fours with the Balfour-Bannerman case. Claude is aware that he might be wrong in his belief that Bonn is the capital, but reasons that even if he is, there is still a good chance that he is right in his belief that the name begins with a B. That reasoning is perfectly sound, and not just because the capital was in fact moved to Berlin. It would still have been sound reasoning, had Frankfurt or Hamburg been chosen. The problem then would have been not lack of justification for the belief that the name began with a B, but its falsity.

The reasoning would also have been sound if Bielefeld had been chosen, but then the truth of the belief that the name began with a B would have had no connection with Claude's reasoning, and we would probably have wanted to say that Claude's belief did not qualify as knowledge.

Let us return to the real world, in which the capital is moved to Berlin, Claude's reasoning is sound, and the truth of his belief that the name begins with a B is connected with his reasoning. Does he know that the name begins with a B?

It may depend on how Claude assesses the risk that the capital has moved. If he thinks there is a pretty good chance that the capital has moved, that supports a claim to knowledge, because it gives significance to the reasoning that Berlin would be the most likely new location. In giving significance to that reasoning, it also gives significance to what it is that actually makes the belief true. Claude reduces his reliance on the false lemma (that Bonn is the capital), and increases his reliance on the true lemma (that Berlin is the capital). If, on the other hand, Claude does not think it at all likely that the capital has moved, then his conscious reliance is on the false lemma, and the reasoning about the move is merely a precaution, upon which he does not expect to rely. We might then wish to deny Claude knowledge.

There is one more twist. Suppose that Claude thinks it is quite likely that the capital has moved, and that inclines us to allow him knowledge that the name begins with a B. That puts pressure on the quality of his reasoning that if the capital has moved, it has moved to Berlin. He cannot be sure of this. So unless he has good reason to think that any move would be to Berlin, with no other city in serious contention, we might not allow him to know that the name began with a B after all.

Phenomenal consciousness

An e-mail has just invited me to consider whether phenomenal consciousness is a causally inert epiphenomenon, and a pointless by-product of brain activity. It is the sort of question that can be transformed into a different question.

First, to what does the claim amount?

It is not a claim about self-awareness of the type that underpins an agent's knowledge that the actions that she can make happen just by thinking, are the actions that will take place in her immediate vicinity, and are performed by the entity that must be kept fed in order for her thought processes to continue. That sort of self-consciousness can be characterized as having a grasp of what Perry called the essential indexical. It is the sort of self-consciousness that lies at the heart of Lucy O'Brien's argument in her book, Self-Knowing Agents. It is something that must be represented in our brain cells, one way or another, in order for us to function as we do.

Rather, the claim is about how things feel to us, the qualia (or apparent qualia, if one thinks that there are no qualia) that we have, but that zombies would not have. So the second part of the claim, that phenomenal consciousness is a pointless by-product of brain activity, is a claim that zombies could do just as well as we do. It might happen to be that any creature that functioned as we function could not be a zombie, for example, because we would need to wire up the cells in certain ways which would inevitably produce phenomenal consciousness as a by-product. But even if that were so, the second part of the claim could still be made. It would merely need to be worded as "Disregarding the practicalities of making zombies, they could do just as well as we do".

If, however, one were able to substantiate the second part of the claim, in the form of a claim that zombies could do just as well as we do, that would not mean that we would have established the first part of the claim. (It may be that the second part of the claim could be taken in some other form, such that substantiating it would substantiate the first part of the claim, but it is not obvious how to re-cast the second part in order to give this result.)

We would not be able to move straight from the second part to the first part, because phenomenal consciousness might be causally effective in human beings, creatures who have it, even though an alternative way of achieving the same results that we achieve, an alternative that did not involve phenomenal consciousness, would be available. We should not suppose that the difference between a human being and a zombie is simply the presence or absence of phenomenal consciousness, with no other differences. And if there are other differences, such that we would not get from a zombie to a human being simply by adding phenomenal consciousness, those differences could build in a causal role for phenomenal consciousness.

We need to say something about how phenomenal consciousness could have a causal role. It could be said that only fundamental particles and forces have causal roles. But that would be a very narrow way of speaking. We are more inclined to say that macroscopic objects also have causal roles. Now suppose that a subject has his fingers on some buttons, which carry modest electrical charges that produce a pleasant tingling sensation, but which are also getting steadily hotter. If a particular configuration of brain cells corresponded to a particular feeling in the subject, and could not be picked out in any other way than by saying "this is the configuration when the subject feels heat at his fingertips", and an analysis of his brain processes showed that the configuration led to conscious thoughts about when it would become sensible for him to withdraw his fingers and forgo the pleasant tingling sensation, then it would not be obviously inappropriate to say that the feeling played a causal role, any more than it is inappropriate to say that a ball that rolls off a table and onto the floor plays a causal role in making a noise, rather than saying that the particles of which the ball is comprised play causal roles in disturbing particles in the atmosphere. Berent Enç's thoughts on causation and conditionals, in his book How We Act, are relevant here.

It would not be obviously inappropriate to speak in that way, but it might still be inappropriate. What might make it appropriate, or inappropriate?

A claim of appropriateness would best be sustained by a claim that states of phenomenal consciousness were on a par with macroscopic physical objects. There is a sense in which both are not really there, but are mere causally inert epiphenomena of the fundamental particles and forces. If they were causally inert in the same sense, that would strengthen the position of those who said that it was appropriate to regard states of phenomenal consciousness as more than epiphenomena, to the extent that it was appropriate to regard macroscopic physical objects as more than epiphenomena.

So the new question, into which we can transform the original question, is this: Are states of phenomenal consciousness epiphenomenal on the fundamental particles and forces, in the same way as macroscopic physical objects?

One reason to say that states of phenomenal consciousness and macroscopic physical objects were epiphenomenal in different ways, would be that laws of the same general type, physical laws, give us a grip on the behaviour of particles, and on the behaviour of macroscopic physical objects. It is a debatable claim, but not a crazy claim, that we could derive the whole of chemistry and biology from physics, too. (This is an upwards claim, different from the claim that we could reduce biology and chemistry downwards to physics.) We could claim that any emergence would not obstruct such an upwards derivation.

But then, could one also argue that no emergence would get in the way of an upwards derivation of facts about states of phenomenal consciousness? If it would not, and if this upwards derivation were feasible, we would have failed to separate off consciousness as something different from biology in a relevant way.

One sign that there might be an obstacle to such an upwards derivation is that descriptions of states of phenomenal consciousness are readily appreciated by us, but they might not mean anything to, for example, Martians, whereas human biology would be perfectly meaningful to Martians.

Another sign is that we do not yet have much idea of what such an upwards derivation would look like, whereas we have a pretty good conception of upwards derivations of chemistry, and of biology, from physics. But it would be unwise to assume that this is how things will rest. Our knowledge of the brain has advanced enormously over the last 20 years. We do not know how much we will learn in the next 20 years.

Finally, we must consider the objection that if we did see how facts about states of phenomenal consciousness were to be derived, the descriptions of the derived objects would not look like descriptions of states of phenomenal consciousness. They would be descriptions of brain states. The descriptions would not glow with the feelings that we have, when our brains are in those states. But it is only Martians who definitely could not see the descriptions as glowing with those feelings. If we were to follow a Churchland-type programme of reform of our manner of speaking, so that we started to speak in terms of brain states, and if we associated descriptions of brain states with inner feelings, the descriptions might well come to glow with the corresponding feelings, even when we read them in neurology textbooks.

Wings of Desire

Every so often in the film Wings of Desire (alternatively entitled Der Himmel über Berlin), directed by Wim Wenders and released in 1987, we hear extracts from the Lied vom Kindsein, by Peter Handke. The text is here:

http://www.wim-wenders.com/movies/movies_spec/wingsofdesire/wod-song-of-childhood-german.htm

and an English translation is here:

http://www.wim-wenders.com/movies/movies_spec/wingsofdesire/wod-song-of-childhood.htm

Plenty of lines in the Lied illustrate the claim that philosophy begins in wonder (Plato, Theaetetus 155d; Aristotle, Metaphysics 982b11-13): for example, "Warum bin ich ich und warum nicht du?"; and "Wann begann die Zeit und wo endet der Raum?".

It would be an interesting exercise to answer all of the questions that the Lied poses, and an equally interesting one to make all the connections that could be made between the text of the Lied and contemporary philosophy. For example, "Wie kann es sein, daß ich, der ich bin, bevor ich wurde, nicht war, und daß einmal ich, der ich bin, nicht mehr der ich bin, sein werde?", invites us to think about the conditions under which indexical and non-indexical terms can refer, and about the peculiar effects of using non-indexical terms to refer to oneself (with echoes both of Moore's Paradox and of Perry's essential indexical), as well as inviting us to think about coming to be and ceasing to be.

I shall here take a look at these words: "Ist das Leben unter der Sonne nicht bloß ein Traum? Ist was ich sehe und höre und rieche nicht bloß der Schein einer Welt vor der Welt?".

They have a particular relevance in the context of the film, in which angels see the world and the people in it only in black and white, and they cannot intervene causally to change people's lives, but on the other hand, they can listen to people's thoughts. But let us allow ourselves to go beyond that context, and ask what connection there may be between the idea that life is merely a dream, and the idea that we may perceive only an appearance, rather than the world.

I shall take the former idea to be that life is but a fleeting set of impressions, which if properly understood, could not be taken to be of any importance. The sentiment here is Pindar's, that a person is but a dream of a shadow (skias onar: Pythian Ode 8, line 95), ignoring the comfort that the following two lines give, with their reference to the effects of Zeus's favour. If we take the idea that life is a dream to concern importance, that idea is kept securely, and interestingly, separate from the idea that we do not perceive the real world. If we took the former idea to concern the process that produced our perceptions, then there would be a risk that the two ideas could come together, especially if it were possible to have dreams that were reliably veridical, for example by virtue of a mechanism of pre-established harmony, or by virtue of some unknowable that produced both the real world and our perceptions in parallel.

I shall take the latter idea to be that we perceive an appearance of a world, where that perceived world is distinct from the real world, and stands between us and the real world. The presence of the additional world, required by the text ("der Schein einer Welt vor der Welt", not "der Schein der Welt vor der Welt"), might be thought to steer us towards the sort of picture that would be given by a two-world interpretation of Kant, but we must allow for two non-Kantian elements. The first is that there is no requirement to regard the perceived world as empirically real. The second is the possibility (but not the certainty) that the perceived world is straightforwardly caused by the real world. The talk of our perceiving an appearance of the additional world also gives scope to introduce sense-data, or some such intermediary, but that is not the main point. The essential thing is the additional world.

First, suppose that life was a dream, in the sense of unimportance that I have just given. Could it be that we would nonetheless perceive the real world, and do so accurately - or, alternatively, perceive an intermediate world that was like the real world in its details, so that we at least had an accurate representation of the real world, and arguably did (indirectly) perceive the real world?

We could, so long as we could not act in the real world. That is, we would need to be in the impotent position of the angels in Wings of Desire, or of the deceased in Sartre's Les jeux sont faits. That would be both necessary and sufficient to make our perceptions of no importance, even though what was perceived or at least represented to us, the real world, was of importance, and even though the perceptions of people who could act in the real world, perceptions that might be qualitatively identical to our own, would be important.

If we could act to change the real world, perceptions that conveyed the state of the real world would matter, no matter how convoluted the process by which they conveyed that state. Perceptions of a world that was not the real world, and that did not convey the state of the real world, would not matter. They would be like the dreams that we, real agents in the world, in fact have when we sleep. Those actual dreams do not matter, except perhaps in indirect ways that do not rely on the accuracy with which they represent the real world.

Now suppose that life was not a dream, in the sense that our perceptions did matter. Would that impose any restrictions on the perceptual process?

We would need to be able to act in the real world, in order for our perceptions to be important. But our perceptions would also need to be useful guides to action. They would not need to give us wholly accurate information about the real world, but they would need to be such that paying attention to them led to action that was, on the whole, more appropriate than our actions would be if we did not pay attention to them. They could, however, fulfil that condition, whether we perceived the real world or some other, intermediate, world.

Manipulating the distribution of lifespans

Suppose that you have the power to alter people's lifespans, but only on a statistical basis, not person by person. Perhaps you can do this through genetic engineering, or through putting something in the water supply. (As is normal in philosophical thought experiments, we shall not worry about practicalities.) Furthermore, you cannot ask people's permission before acting, and you are the only person in the world who can take this action.

To be precise, you can take, or refrain from taking, action that will have the following effects. The effects are only on offer as a single package: you cannot pick and choose selected effects.

A. The mean of the distribution of life expectancies for the affected group will rise.

B. The dispersion of that distribution will fall, but the overall shape of the distribution will remain unchanged. If, for example, the distribution was normal, it will remain normal, but with a lower standard deviation. The fall in the dispersion will be great enough to ensure that despite the increase in the mean, there is some age, above which the high-lifespan tail of the new distribution will fall below the high-lifespan tail of the old distribution. (Both distributions are to be given in terms of proportions of the populations to which they apply, so as to avoid issues about the effects of a higher mean on the size of the population.)

C. The mean of the distribution of years of ill health or disability at the end of life, and the overall shape and the dispersion of that distribution, will remain unchanged. Note that this effect is given in terms of years, not in terms of proportion of life. So the number of years of ill health or disability remains the same, even if lifespan increases.

D. Any correlation between position in the distribution of lifespans, and position in the distribution of years of ill health or disability, remains unchanged.

Thus, average prospects will improve: longer life, with no more years of ill health or disability at the end of life. But there is a tail of the distribution of lifespans, in which prospects are made worse by the change.

Now we come to the questions.

1. Should you take this action, if it is to apply to all people already born or currently in the womb, but not to anyone else?

2. Should you take this action, if it is to apply to all people who have not yet been conceived, but not to anyone else?

3. Should you take this action, if it is to apply to all people already born, currently in the womb, or not yet conceived?

Two points should be noted, before we consider answers.

The first point is that you are confronted with a single choice: take the action, in accordance with the terms of whichever one of 1., 2., and 3. is in force, or do not take the action at all. You are told which of the three is in force. You do not get to choose which one is in force.

The second point is that in drawing a line at conception, I do not mean to take a stance on whether embryos are people. I simply want to recognize the difference between entities that already have a determined genetic endowment, and potential entities that do not. The significance of genetic endowment, is that it is likely to have quite a lot to do with prospects for lifespan and for infirmity in old age.

The case against taking action in 1. looks quite strong. Given that genetic endowment and lifestyle to date have a substantial influence on lifespan, there would be some group of people, ones with good genetic endowments and healthy lifestyles, who constituted a modest proportion of the population, such that we were aware of the criteria for membership of that group, and such that we could say that taking the action would shift the odds against members of that group, to an extent that one would not regard as trivial. Kantian objections to the use of people as means to other people's ends come to mind. The other people in question would be the people outside the group.

The fact that the members of the group would be people who were already well off, in that they would be people at the high end of the distribution of lifespans, hardly seems to be a satisfactory response. Imposing reductions in lifespans seems to be rather more fundamental than imposing high tax rates on high incomes.

My initial feeling is that the obvious utilitarian case for taking action in 1. is outweighed by considerations such as these.

One objection to this view, would be that a decision not to take the action would itself be a decision to act: that is, that refraining from action would not be abstention, but a positive choice for the other side, and that one would be just as responsible for that as one would be for a choice to take the action, and responsible in the same way. Then a choice not to act would amount to deliberately disadvantaging those who were not in the group with long life expectancies. I shall not explore this view here, but it is a view that could be argued.

The case against taking action in 2. looks much weaker. People as yet unconceived have neither any particular genetic endowment, nor any particular lifestyle. It is tempting to say that there would be, in the future population, some members of a specifiable group of people (the group of people with good genes and healthy lifestyles), who would be worse off than they would have been, had the action not been taken. But that objection would not be rightly phrased. The word "they" would have no referent. The complaint that some members of a specifiable group would be worse off, once re-phrased to remove this difficulty, can amount to no more than a complaint that the distribution of lifespans, for the whole population, would be different. Given that, the utilitarian case seems to be a good one. In 2., a choice to take the action would be the right choice.

It might seem that the word "they" would have a referent, at least in the next few generations, if there was a strong hereditary element to longevity. It could refer to the descendants of people who were currently alive and who had good genes. But I doubt that this would be enough to create a referent. Since we are concerned with people not yet conceived, there would only be potential descendants. Any particular person currently alive and with good genes might not have any descendants, even though it would be very probable that some people or other, drawn from the set of those currently alive and with good genes, would have descendants.

There is a parallel with John Rawls's veil of ignorance. It is a veil of total ignorance. The people behind it have no particular characteristics, until they are dropped into the society that they have designed. So they can only sensibly think about overall distributions. There is a sense in which they cannot take up arms on behalf of a particular group on the basis that some arrangement would do an injustice to its members, even though criteria for membership of the group may be perfectly clear, because no-one has, at the time of design, characteristics that would determine whether he or she was a member. "Its members" lacks a referent. To make the parallel closer, we can imagine Rawls's deliberators thinking about possible changes to distributions that already apply in an actual society, a society which all the designers will join as a complete replacement population, in roles and with characteristics that will be allocated at random, once all existing members of the society have died.

I shall not reach any conclusion on the third possibility, applying the change to current and future people. The key question is this. If the future population will be, in total over the centuries, very much larger than the current population, can the utilitarian case for action outweigh the case against action that was set out in relation to 1.?

There is one more complication. Is it in the interests of a person to have descendants who enjoy long lives? If it is, then that would influence one's thoughts in relation to 3. Currently living people with good genes might lose some of their own lifespans. But suppose that the beneficial influence of good genes on lifespan was not passed down the generations to any significant extent, so that, for example, the great-grandchild of someone with genes that substantially improved prospects had no better chance than the average in the population of having genes that conferred such good prospects. Then the good genes of the current generation would not tend to keep a significant proportion of their descendants in the group that would potentially lose from the action. Then the members of the current generation with good genes might have self-regarding reason to favour the action.

Opposition to consensus

One of the complaints against those who deny, or doubt, anthropogenic global warming, is that they are mistaken. That must be the fundamental complaint. We won't do the right things, unless we get the facts right.

Another complaint, less fundamental but more interesting ethically, is that by opposing the scientific consensus, they get in the way of action. This complaint is sometimes mentioned, for example in paragraph 7 in this piece by James Garvey:

http://www.guardian.co.uk/environment/2012/feb/27/peter-gleick-heartland-institute-lie

There will always be some politicians who will oppose action on global warming, and if some people offer arguments that action would be wasteful and pointless, they will give those politicians material to use in their own campaigns. This will reduce the probability of action at the level of governments, whether they would work singly, or in co-operation at the international level.

My question here is, is there a specific ethical failing of opposing a consensus, where the result is likely to be to delay action, or to reduce the scale of action, to solve a problem that is real and pressing if the opponents of consensus are indeed mistaken?

If the opponents know that the evidence for their position is of poor quality, or if they are reckless as to whether it is of good or poor quality, there is a failing, but it is of a rather more general sort than any failing of opposing a consensus. The failing is that of not being sufficiently careful to put forward true claims, and to avoid making false claims, in a situation in which one ought to take more than usual care, because the consequences of people being misled are so serious. William Kingdon Clifford set a high standard here, in his essay "The Ethics of Belief". His standard is conveniently summed up in his words towards the end of its first section: "It is wrong always, everywhere, and for anyone, to believe anything upon insufficient evidence". We might debate whether this was an appropriate standard when the stakes were very low. But with global warming, the stakes are very high, and the standard is undoubtedly apt.

Not all global warming sceptics are reckless as to the quality of the evidence for their position. Some would be too ill-informed to be aware that the quality of their evidence needed to be reviewed. But the corporate lobbyists, and their think tank pals, who push the sceptical position, cannot plead that kind of innocence. They know about the evidence. They study it when formulating their positions. They also know about the need to look critically at the quality of evidence. They spend a lot of time criticizing the evidence on the consensus side. Given that the overwhelming majority of scientific, as distinct from political, commentary, is on the side that anthropogenic global warming is real, it must be reckless for them to take a contrary position, unless they have a large and thoroughly-analysed body of evidence to support that contrary position. The corporate lobbyists and think tanks that take up global warming scepticism have no reason to suppose that they have such a body of evidence. They are, therefore, at best reckless, and they stand condemned by Clifford's standard.

This does not mean that there is anything wrong with their challenging the detail of the scientific claims that are made, searching for errors, and highlighting alternative interpretations of the data. It does, however, mean that they should not crow that there is no sound support for the consensus scientific view, when they have no good reason to think that they have established that the consensus scientific view is baseless. One can be reckless, not only in taking up an overall position, but in making claims about how much one has shown, or about the extent to which the things one has shown undermine the other side's view.

Now let us leave the example of global warming, and ask whether there is a specific ethical failing of opposing a consensus, assuming that:

(1) the opponent of the consensus is not reckless as to the quality of the evidence for his position;

(2) if the consensus is correct, failure to act as the consensus view would recommend would have serious consequences;

(3) if the consensus is mistaken, there would be significant waste in acting as the consensus view would recommend.

It seems to me that there is no ethical failing here, unless, perhaps, the opponent of the consensus is in a position of exceptional power, so that his position is very likely to prevail, whatever the merits of the arguments on his side and on the consensus side. Absent such power, the opponent is acting in a way that is, in general, likely to lead to the advancement of our knowledge. The opponent is simply engaged in subjecting other people's claims to criticism. Criticism exposes error, and can strengthen correct positions that show themselves able to withstand the criticism, as Mill remarked (On Liberty, chapter 2).

What if we leave out condition (3), and suppose that while serious loss would follow from failing to act on the consensus view if it were correct, there would be no serious loss from acting on the consensus view if it were incorrect?

We might take the attitude of Pascal's Wager: we might as well act on the consensus view anyway. Then it might seem that opposition to the consensus view would be reprehensible, if it would be likely to hinder that desirable course of action.

However, even assuming that action on the consensus view would be the only sensible thing to do, and that opposition might hinder that course of action, it would not follow that opposition would be reprehensible. Opposition could still fortify belief in the consensus view, as suggested by Mill, if the opposer's arguments were found wanting. And if we were to adopt Clifford's attitude, we would want opponents of the consensus to be as active as they could be, in order to root out any mistaken beliefs that might happen to be held by the majority. That would be so, even if retention of the beliefs in question would not lead to any immediate adverse consequences, whether they were mistaken or correct. It would be so, both because an accumulation of erroneous beliefs, individually harmless, might have adverse consequences long after the beliefs were acquired, and because truth is something that is to be valued in itself.

Tricks of presentation

Yesterday, I saw the new David Bowie exhibition at the Victoria and Albert Museum. The exquisitely curated sequence of pieces of music, video clips, costumes, and other artefacts, demonstrates the power of presentation, far more than a single concert would do. I suppose the reason is that when we see contrasting tools of presentation, used in different concerts, we become aware of what each tool does, because it does not do quite the same as the corresponding tool in the next display. But we can remain carried away by each act of a pop star, because we know it is only an act. It does not profess to convey anything much about the Universe.

Now suppose we saw an exhibition of papal inaugurations and other grand religious ceremonies, and we therefore became more aware of how the tools of presentation worked in each one. Those who are currently carried away by such shows might cease to be so, because when something that is supposed to be more than an act, and to represent a point of contact with some profound truth about the Universe, is revealed to be shot through with tricks of presentation, doubt must be cast on the supposed profound truth. It should not need those tricks. And if the supposed profound truth is discarded, the show ceases to be a piece of fun, and is reduced to a charade. It cannot survive the loss of its raison d'être.

It is tempting to define an epistemic virtue, and its corresponding vice, in the following terms.

1. Suppose that there is some information.
2. The information might be presented in a variety of ways.
3. We shall only consider ways that would allow the subject to grasp the information.
4. The subject may form a view on the information's truth, or on its trustworthiness.
5. A propensity to form the same view, regardless of the way in which the information was presented, would be an epistemic virtue.
6. A propensity to form different views, depending on the way in which the information was presented, would be an epistemic vice.

This virtue and vice would come close to the virtue of scepticism (in the sense of being appropriately critical, not the Pyrrhonian sense or anything close to that sense) and the vice of gullibility, but the focus here is on the method of presentation, not on any other ways in which people might avoid being led astray, or might be led astray.

We could not test for the virtue, or the vice, in a given individual, by presenting the same information to him or her several times, in different ways, because the individual would remember previous presentations. We might use repeated presentation, with different forms of presentation being used in various orders, on a large sample of people, to test for the effectiveness of different methods of persuasion across the population as a whole, but that would be a different exercise.

We might note whether an individual was in general susceptible to the vice, by seeing whether he or she tended to accept the content of adverts or of propaganda. But our conclusions would probably be impressionistic, rather than based on a rigorous consideration of evidence. Indeed, if someone comes along with a test that purports to tell us whether a given individual is, or is not, uniformly susceptible to persuasion through the use of tricks of presentation, we should be sceptical of that claim.