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Computational Metaphysics

"Let the whole outside world consist of a long paper tape…"
                                                                                                            John von Neumann 1948

Thought experiments are the metaphysician's primary tool.  Limited only by logic we can test metaphysical hypotheses at any possible world we can imagine.  But imagination has its limits.

Can we imagine two possible worlds, each entirely empty except for a single object; the difference being only that one object is stationary whereas its counterpart moves?

In possible worlds containing only two particles perpetually moving relative to each other but never colliding, must there be a determinate answer to what would happened if they did collide?

If the actual world were changed at the moment of the Big Bang just enough so that Romney would have won in 2012, would his opponent still have been Obama?

Much can hang on how we answer questions like these but answers are not easy.  The possible worlds in question seem either too poorly furnished or too cluttered with bewildering detail for imagination or argument to get a grip.

In this post I want to introduce a new device for thinking about metaphysical problems; they are a kind of philosophical workbench on which we can test competing metaphysical theories.   I call them "Turing Worlds".

In this post I am not going to use Turing Worlds to advance any very radical metaphysical thesis. Instead I'm going to show how some well know problems play out in these worlds.  Think of it as an exercise of calibrating a new tool against known quantities.

Turing Worlds

Roughly: a Turing World is a possible world whose workings are entirely comprehensible as the operation of a Turing Machine.

I will assume all readers have got the gist of Turing machines. Here is a particularly nice example.

The video shows an actual machine.  That is, it shows a machine embedded in the actual world and governed by actual physics. This requires there be a lot of hidden electronics behind the scenes that we would have to understand to really understand how it works.   It is only a superficially simple machine with complex inner workings embedded in our complex world.

To build a Turing world we want to abstract away as much of the complexity as we can.  So, to a first approximation, we can think of a Turing world -- as Von Neuman instructs-- as a tape; infinite in length; divided into cells; each cell occupied by a zero or one.

Figure 1

At any given moment there will be one cell whose contents are directly relevant to what happens next.  Intuitively, this is the cell that is under the scanner but we can do without the apparatus of the scanner itself: in my illustration I have substituted a blue glow.

The scanner position changes over time; moving left or right relative to the tape but never moving more than one cell at a time.   Before the scanner moves it prints either a "1" or "0" on the selected cell.  Sometimes this changes the contents of that cell, sometimes not.  Sometimes the scanner prints a symbol but does not move.

Figure 1 depicts the sort of world Von Neuman described but — with all due respect to that great man— there must be more to a computable world than what we see here.  In a Turing machine what happens next doesn't just depend on what symbol is under the scanner; it also depends upon the machine's computational state.  Computational states are features of the world that vary over time in systematic ways that can result in something different happening even when the same symbol is at the scanner.

To build Turing worlds we will have to give them computational states.  It is easy to imagine what the computational state of a Turing world might be-- think of the kind of hidden machinery that drives the machine in the video.  It is far less obvious what a computational state metaphysically must be. For the purposes of this post I am going to assume that the computational state of a world at any moment must at the very least correspond to some intrinsic property of something in that world at that time; some property that changes over time.

Staying as neutral as I can about what those properties might be I'll build this into my illustrations of Turing worlds with a simple label as in figure 2, illustrating worlds in states A and B.

Figure 2

With states in the picture we can describe what happens in a Turing world will in terms of the transition rules of that world.  Here is a table of transition rules for a very simple Turing world.

Table 1

The state diagram on the right describes the same transitions as the table on the left.  The machine/world depicted here has two states, 'A' and 'B'.   The table tells us, for example, that if in state 'A' when a '1' is under the scanner cell, the machine will do '0→B':  that is, it will print a '0', move the tape to the right and move to state B.  The '↓' symbol means the tape does not move.

The transition table for an actual Turing machine like the one in the video gives an abstract description of its workings but the reason the actual machine instantiates one table rather than another— indeed, the reason it works at all—depend on its underlying machinery.   Tinkering with that machinery can change the table that describes it.

Which brings us to the signal difference between a Turing World and a world that merely has a Turing machine in it.  I stipulate as a matter of definition:

(D1)	The transition table that describes a Turing World must be entailed by the physical laws of that world.

One way of framing this requirement would be to say that the transition rules of a Turing world are it's laws.  I myself am happy with this way of putting things, but this formulation might be contentious.

There are metaphysical theories that require laws, properly so called, to be rooted in particular kinds of intrinsic properties of things, or of universals, or in relations between universals.   Whether or not that is so is a question that I think Turing Worlds might help us figure out.   But that is a good reason not to beg such questions from the outset.  Better, instead, to say, more cautiously, that the transition table of a Turing machine describes certain regularities and stipulate— as (D1) does — that  a Turing World corresponding to a particular transition table will be a world where those regularities are nomological.   That leaves us free to argue later on about precisely what 'nomological' might mean.

While (D1) is neutral on the question of whether Turing transition rules could be the basic laws of any world, I will continue to depict the ontology of Turing worlds in the austere manner of Figure 2 and talk as if their transition tables exhaust their physics.  If this leads to disagreement down the line we will have learned something about the upshots of our different assumptions about the laws.

I take it as uncontroversial that there can be and in fact are physical processes which are a) describable in computational terms b) proceed as they do as a matter of physical law.  The encoding of proteins by DNA is an obvious example.

With these caveats in place we should all be able to agree that Turing Worlds are metaphysically possible.  They are real possible worlds in whatever sense possibilities are "real".   That means that generalizations over possible worlds of the sorts that metaphysicians are wont to give ought to apply to Turing Worlds and  we can test metaphysical hypothesis by seeing if we can construct Turing Worlds that refute them.

A Few Short Steps to the Gallows

Beware gentle reader! To pass beyond this point is begin a quick march to a place you would rather not go. Be prepared to make tough choices. Watch your step but try to keep up with the group.

We begin with a version of Robert Nozick's "Falling Man" case. 

INNOCENT FALLING MAN
Sam is standing at the bottom of a well when a large man accidentally falls in at the top and hurtles down towards Sam.  Sam can't get out of his way. When he lands the falling man's bulk will certainly kill Sam instantly but, with Sam cushioning his fall, the falling man will certainly survive. Sam happens to have in his possession a ray gun which is capable of vaporizing the falling man, saving Sam's life.

Is it morally permissible for Sam to vaporize the fat man? Nozick thought so. Yes, the falling man is innocent. He does not want to kill Sam. But Sam is innocent too and he has a right to self-defense. That was Nozick's point.

Not everyone agrees. Some philosophers think you don't have the right to defend yourself against innocent threats. So let us roll back and start at what I hope is bedrock common ground.

VILLAINOUS FALLING MAN
Sam is standing at the bottom of a well as before. But this time the large man jumped in deliberately.  He wants to kill Sam; believes that his falling bulk will do the job and is confident that — with Sam's body cushioning his fall— he will walk away unharmed. Sam knows all this and he still has that ray gun.

Is it morally permissible for Sam to vaporize this falling man?  Surely!  This is attempted murder. Sam would be acting in self-defense.

If you don't believe you have the right to self-defense—ever— you should certainly stop reading now and, well... best of luck to you in your future endeavors.

Are they gone? Good. Let us proceed.

INNOCENT FALLING MAN II
Same as the first case: Innocent man hurtling towards Sam. But now Sam doesn't have a ray gun. He has an ordinary gun. The falling man would be hard to miss so Sam can be confident of wounding him; perhaps fatally. But this won't stop the falling body or prevent Sam's death.

Knowing all this (somehow, suppose) may Sam use his gun?

Notice that if Sam does shoot in this case we cannot properly describe what he is doing as "self-defense". Shooting doesn't defend him from anything. It would be more accurate to call it retaliation — preemptive retaliation — for the harm the falling man is about to inflict on him; is this permissible?

I myself don't think so. The falling man is innocent. Hurting him is not going to save Sam's life. For him to deliberately harm this innocent person seems to me gratuitous, spiteful and morally wrong.

If you disagree with me about this— if you think it is permissible for Sam to retaliate however innocent the falling man may be— then you can stay with us but I won't be talking to you in what follows. Try not to get too far out front of the group (and stay well back from me.)

Next step:

VILLAINOUS FALLING MAN II
The same as VILLAINOUS FALLING MAN except that Sam now has only the ordinary gun. If Sam shoots he will certainly injure, and perhaps kill, the falling man. The falling body will still kill Sam, but the villain won't walk away unscathed.

Given that this falling man is trying to murder him, would Sam be doing something morally wrong if he were to shoot in this case?

What do you think? Okay, settle down. I can hear some of you complaining (there are always some) about these fanciful philosophical "what ifs". How can you be expected to have robust moral intuitions in response to these unrealistic fables?

Alright. Gloves off. Remember you asked for this.

RAPIST
Sally, a small frail woman, wakes in the middle of the night. There is someone in her room. Instantly she realizes who it must be.

In recent months her community has been terrorized by a serial rapist-murderer. His modus operandi has been publicized by newspapers and television. He tortures, rapes and kills his victims. And it is well known that the more his victims resist, the crueler his attack. Sally has seen an interview with the only victim to have managed, barely, to survive her injuries. She credited her survival only to her extreme passivity and obedience to the rapist's commands. 

Sally cannot escape. She is alone. She can seem him now: a huge, muscular brute. She could claw and kick at him, and perhaps inflict a little pain, but she cannot hope to stop him.

Realistic enough for you?

Now there is a difference between this case and last FALLING MAN story. The difference is that Sally has a positive, prudential reason not to hurt the person who is going to harm her: she will improve her chances of survival (slightly) by not fighting back. So, prudence dictates that Sally should lie back and accept her fate. But prudence is not morality. Our question here, as before, is: is it morally permissible for Sally to try to harm the rapist even though she knows that doing so will not deter him?

Before you answer, make sure you understand the question. You are not being asked here for general crime stopping tips or proscribing for every possible case of rape. The question is whether or not it would be morally wrong for Sally, this particular woman, to hurt this rapist, this particular monster, before he kills her. And be careful not to read into the story elements that aren't there. Maybe you think, or want Sally to think, that she can scar her attacker in ways that will make it easier for the police to apprehend him after her death. 
 Maybe you think, or want Sally to think, that by fighting the rapist she may deter him from future crimes. Sorry, no. This is my story and none of those things are true in my story.

So, what do you think?

My own view is that it is morally permissible for Sally to try to hurt the rapist. I think she may fight him tooth and nail. She may bite, kick, and scratch. She may try to claw his eyes out. I do not think it would be wrong for her to do so even if she knows to a certainty that it will not save her.

And let me be clear: I am not just saying that it would be understandable if she fought back. I am not saying that, given her extreme circumstances, violence on her part is forgivable. I think there is nothing to forgive; if Sally manages to harm the rapist, she will not have done anything wrong.

If you do not agree— If you think it would be every bit as wrong for Sally to try to hurt the rapist as it would be for her to attack some random, innocent stranger on the street— then you need read no further. Thank you for playing.

Experimental Philosophy:A Modest Proposal

The practice of  Experimental Philosophy  appears to be wholly comprised of administering questionnaires to the philosophically naïve in order  to ascertain their philosophic "intuitions" .  

My  proposal  is simply  that in writing up their results the experimenters should feel obliged to include at least one section in which they, the  experimenters, say what they believe are  the correct answers  to each of the questions they have asked.  Where the  experimenters' opinions diverge from their subjects’  revealed intuitions, the experimenters should  try to explain why the subjects  got it wrong. 

This requirement   would  sensitize the experimenters and alert the audience to potential issues of experimenter bias--always  danger  in any kind of survey -- and would also have the salutary benefit of ensuring that some actual  philosophy was done in the course of the proceedings.

The Origins of Property II

The Morals

First, some quick clarifications.  

I deprived the tribe of a moral vocabulary to lubricate the storytelling.  I do not claim the tribe as described are without morality.  Indeed as an advocate of Retributive Ethics I think that pretty much all of morality is already implicit in the principle, "No bullying".

This is a story about the origins of some kinds of property, not morality.  Readers of these posts will recognize it as a dramatic staging of the Retributive Theory of Property. But you do not have to be a Retributivist to think that hurting others is, except in exceptional circumstances, a morally bad thing. And if you agree with that then you should agree that in following The Rule our natives are doing the right thing.

The Rule, as the natives understand it does not ban all violence and I assume we agree that the exceptions it allows are also morally correct. For example, The Rule allows violence to stop bullying and I take it that we agree that it is morally permissible to use violence in defense of ourselves or others.

Another circumstance in which The Rule permits violence is the one in which one person gives another permission to do him harm and I expect all readers to agree that in this circumstance too violence is morally permissible. When one football player tackles another he is doing violence that would get him arrested outside the arena but-- provided the violence is within the agreed to rules-- we don't think his actions on the field are morally wrong. We think it is permissible for the players to knock each other around because they have given each other permission to do so. No one denies this, so I won't bother arguing for it here but will note that this aspect of our moral authority over ourselves-- our power to permit violence against ourselves-- has been mostly overlooked by philosophers, though it is central to Retributive Ethics.

If you agree to this much then it seems to me that you must agree that the permissions the tribe grants Wilt at the end of the story are moral permissions and that his rights vis a vis the plot of land are moral rights.

We think The Rule is morally correct. But notice I neither assert nor deny that the natives themselves regard The Rule as a moral rule—whatever that might mean. I suppose that some might protest that this is a defect in the story. To follow a rule like The Rule mustn't the natives already be convinced that is morally correct by some higher moral standard? Mustn't they think, say, that it maximizes general utility?

No. That is a confusion about rules and rule following.  For my purposes we can regard The Rule simply as a convention in David Lewis's sense. That is, it is a perhaps arbitrary, but self-perpetuating, solution to an ongoing co-ordination problem. That problem is how to maximize chances of survival confronted with a hostile environment and surrounded by potentially hostile neighbors. To make sense of the natives' preference for The Rule neither we nor the natives need to think that it is the only equilibrium solution there could, or ought, to be.

I denied my natives words for "right" or "wrong", but that does not keep them from behaving morally. I also denied them words for "promise" or "contract" or "obligation". Do the natives make promises?

Well note that Wilt does not promise, even tacitly, to fight the next Bear that comes around. Neither does the community promise to reward future bear fighters as they have Wilt. And interestingly neither Bob nor anyone else promises not to forcefully resist if at some point in the future Wilt has to evict them from his land.

Still, some readers Wilt protest, Bob's giving permission to the others to use force against him if he trespasses on Wilt's land functions, in the story, very much like a promise not to go on Wilt's land.

I happily concede the point. It confirms the Retributive Theory of Promising: the view that to make a promise just is to give someone a conditional permission to do you harm.

Now to the morals.

MORAL 1: Hobbes was wrong.  

Hobbes and many after him held that in an absence of government and laws -- in a "state of nature"-- there could be no property.  At the beginning of our story our natives are in that state.  They lack a government and the enforcement of their only rule is voluntary. In Hobbes' terms their situation is like that of sovereign nations interbellum:  a time of truce in a war of all against all.  And yet, pace Hobbes et. al., our natives have property and even an economy.

Hobbes is only a first in a long tradition of confusing the existence of property rights with their successful enforcement.  It is not a confusion that is often made about other rights.  Thus we think that even absent government and laws, people have a right to self-defense.   We think everyone has that right even if he or she is too weak to defend him or herself; even when no one will come to their defense.  They have that right even if they cannot enforce it.

Property rights, like the right to self-defense, are moral permissions ("privileges" in Hohfeld's terms).  To have the right to self- defense is to have the moral permission to forcefully interfere with attackers.   To own some land is to have the moral permission to forcefully interfere with trespassers. At bottom, having that moral permission is all there is to ownership: It is not morally permissible to kick people off your land because it is your property; it is your property because it is morally permissible for you to kick people off it.

But "may" does not imply "can".  You can have property rights even though you cannot enforce them and even if social arrangements make no provision for defending you against their violation. In our story a native's rights against bullying are enforced by the spontaneous vigilantism of the other tribesmen.  That does not give them rights they would not otherwise have but it helps us see more clearly what those rights amount to.

We can see that our tribesmen have property rights even at the very beginning of our story because they have the right to self-defense. The right of self-defense is an ownership right: it is a moral permission to forcefully interfere with others if they should try to trespass against our bodies.  And because our bodies are objects in the world, our ownership in them emanates to other things:  however much I might admire the shirt on your back or the apple in your hand, if I cannot lay hold of them without doing violence to you, then your right to self-defense makes it permissible for you to forcefully prevent me from acquiring them.  

Thus in the state of nature you own what you physically possess. This may not seem much, but our fable illustrates how it might be enough, in principle, to sustain an economic order: a market red in tooth and claw.

MORAL 2: Locke was wrong

In our story Wilt acquires a new kind of property. He comes to own something not in his immediate possession. Things that once belonged to no one-- a vacant plot of land and its contents-- have become his.

How this might come about is a long standing philosophical problem with few plausible answers.

There is the "first use" or "first occupancy" theory : the idea that the first person to discover a thing therefore owns it. This theory is often credited to the wonderfully named Samuel von Pufendorf. Alas, Pufendorf seems to have had no arguments for this arbitrary principle . Why not second use, or third? (In any case, I've always found it hard to believe that Pufendorf really was the very first person to discover this idea. Perhaps he was just the first to shout "Dibs!".)

John Locke's theory was that we begin by owning our own bodies and then by "mixing our labor" with other things -- clearing land, planting crops and so forth -- we somehow mix our self-ownership into these other things. This isn't much of a theory; it isn't even a good metaphor for a theory. As Robert Nozick observed:

...why isn't mixing what I own with what I don't own a way of losing what I own rather than a way of gaining what I don't? If I own a can of tomato juice and spill it in the sea so its molecules... mingle evenly throughout the sea, do I thereby come to own the sea, or have I foolishly dissipated my tomato juice?

But then Nozick himself has no better story to tell. He concedes that any theory of property needs to explain "first acquisition" somehow, and suggests, very tentatively, that it might have something to do with laboring to increase the value of things. For some reason Nozick declined to call this "the surplus value" theory of ownership though the name would have been apt.

Yet Wilt -- our Wilt-- was not the first to discover his land. Nor did he mix his labor with it. Neither upon it did he spin nor did he toil. We could have told our story so that he had never set foot on it before acquiring it. I conclude therefore that discovering first, mixing your labor with or improving things is no more essential to their first acquisition than is killing bears.

It is true that Wilt could be said to have earned his land by doing something the community valued and that all those who gathered round the campfire hoped that by rewarding him they would be increasing the general welfare. But this speaks to their motives for granting him the land, not to the substance of the grant itself. It might turn out that their hopes are misplaced-- that Wilt grows so fat and placid on his little plot of land that he becomes useless during the next ursine attack. Even so, whether or not his possession promotes the general happiness, the land will remain his so long as it is morally permissible for him to kick the other tribesmen off it and it will be permissible for him to do so because they gave him that permission; even if they come to regret it.

The Origins of Property: A Parable with Morals

The Parable

Once upon a time there was a primitive tribe that hunted and gathered in a verdant forest in a temperate clime.  

I call them a "tribe" but that name may mislead if it suggests some rigorous form of  social organization.  In fact, the group was about as un-organized as it is possible for people to be.  There were among them no elders, chiefs, shamans or any other kind of leader with authority over his fellows. With one exception-- which we will soon discuss -- there were no laws, rules or taboos that were obeyed or enforced among them and no judges or police to enforce them.

This lack of norms was reflected in their language which (luckily for our narrative purposes) was much like modern English but which lacked any moral or legal vocabulary.  The natives never spoke of 'right' or 'wrong', 'legal' or 'law'.  They had no words for 'promise', or 'contract' and none for 'property' or 'ownership'.

Even so, as I just averred, there was one rule that the natives generally acknowledged and mostly conformed to. They called it "The Rule".

The Rule: No Bullying!

By 'bullying' the natives seem to have meant, roughly, hurting other people or using force or the threat of force to compel others to do what they would otherwise not do. But not every use of force or infliction of harm was regarded as bullying. 

It was, for example, not considered bullying to use force or its threat to defend oneself or someone else against a bully. The Rule permitted self-defense and "other defense" and this had important consequences for all of tribal life.

To understand these upshots it is necessary to understand that the tribe's aversion to bullying did not mean that they were averse to violence or the use of force. These were hard men and women in a hard time. They hunted for food with primitive tools and competed for game with lions and bears. Many among them prided themselves on their martial skills and relished a good brawl.  They would set to with enthusiasm given any excuse and, under The Rule, defending against bullying was an excuse.  

That meant that any native attempting to push some weaker tribesman around might find the tables quickly turned as many defenders rushed to intervene and -- happily unrestrained by the The Rule— teach the would-be bully a brutal lesson.

Yet The Rule had application even here.  The natives recognized that things could go too far: that using too much force-- more force than was required to stop the bully-- could itself turn into bullying.  If they judged that self-defense was turning into a retaliatory beating, other natives would turn their efforts to protecting the would be bully.  Bullying, even of bullies, was not tolerated.  

Such bullies as there were amongst the tribe were, of course, aware of these dangers and so would be careful to pick victims too weak to fight back and catch them when there were alone.  But when the other members of the tribe heard about such an incident they would track the bully down and force him to make it up to the victim.  So, for example, if the bully had snatched an apple from the victims hand he might be forced find him another. If the victim were injured, the bully might be forced to hunt and gather for him until the victim recovered.  This use of force-- to compel compensation-- was not regarded as bullying and was also exempt from the The Rule.

Sometimes too, if the tribesmen thought the bully was likely to repeat his infraction they might administer a modest beating and threaten him with more, "to teach him a lesson", as they would say.  And these acts and threats of violence were not regarded as bullying either so long as they were proportionate to their avowed purpose-- to prevent further bullying.   

In this way The Rule was self-enforcing: Those who did not obey it were likely to suffer at the hands of those who did. This enforcement depended entirely on the tribesmen's general willingness to intervene on behalf of the bullied and such intervention was purely voluntary.  The rule was not understood to require anyone to defend anyone else --or even to defend oneself-- against bullying. In any case, there was no mechanism for enforcing such a requirement. To attempt to force anyone to fight bullies, everyone acknowledged, would itself be bullying.

The willingness of the tribesmen to come to the defense of their fellows must therefore be counted a kind of altruism; albeit a self-consciously reciprocal altruism. "If I defend my neighbor today, he may defend me tomorrow",  the natives often said.  And just because enforcing The Rule was voluntary, anyone with a reputation as a coward might find himself with few defenders when a bully appeared.  Then too, it was common practice for rescued victims to show gratitude to their defenders by doing them services and favors.  These acts of gratitude were not thought of as payments due or as morally required -- as I said, the natives did not speak the language of contract, debt or  moral obligation-- but as simply prudent since, as they would say, "you never know when the next bully will come round".

Now I said that the native's language possessed no words for "property" or "ownership".  Of course one can have a thing and not have a word for it but the natives certainly did not enjoy the kind of enduring ownership of things that we associate with these words.   

In the morning most of men and women of the tribe would go off to forage for food.  When they returned to the general campsite in the evenings each would look anew for a place to set a fire and bed down, and every night this was a matter of first-come, first-served.  It did not matter if a tribesmen had been the first to discover a particular cozy spot or if that native had (as philosophers say) "mixed his labor" with that campsite by clearing trees or erecting a lean-to.  It didn't matter if that particular native had slept in that particular spot, whenever he could, for season after season.  On any evening he might return and find someone else was already sleeping there and there would be nothing to be done about it.  He could not forcibly evict the interloper because that would be regarded as bullying and the other Tribesman would use it as an excuse to "teach him a lesson".

As it was with land so it was with things.   The natives knew how to knap stone tools and scrape hides for clothing.   But if any other native found a tool or fur sitting unattended she could simply walk off with it and there was nothing the artisan could do to reclaim the fruits of his labor.  He could not use force or even its threat, because that would be regarded as bullying.  

It was the same with the food.  A hardworking native might scramble all day to collect a few nuts and berries but the moment he set them down others who had done nothing all day but lounge by the fire might scoop them up and eat them all.   And there would be nothing the hard working native could do about it. No bullying!  

Observing all this, anthropologists might say that this was one of those communities which lacked even the ""concept of Property".  But then anthropologists say many foolish things.   It was true that any item any tribesman left unattended could be taken by any other no matter what its history or provenance.  But it was also true that once a native had taken something into his possession The Rule protected his possession of it against any who would try to take it away.  

If the fiercest fighter in the village happened to leave his favorite spear unattended for a moment, the weakest tribesman might pick it up and use it as his own.  If the fighter tried to snatch it back his behavior would be regarded as bullying and would invite a beating from his fellows. A beating which would likely end with his being forced to return the spear and perhaps other compensation.   

Likewise, while who-slept-where was a matter of first-come, first-served, once a native had encamped on a particular spot no one would dare to try to forcefully displace her. Thanks to the Rule she was safe, "safe as houses" as they say.  

So a native might be said to own the clothes on his back, the ax in her belt or the apple in his hand for as long as he or she held on to them.  Any native was the sole proprietor of any land where she lay down at night-- until she got up the next morning. Anything that you could only be deprived of by being somehow pushed around was your property by dint of the Rule's protections against being pushed around.   

What each native owned was limited to what he physically possessed at any given time and while this kind of ownership is obviously limited it was sufficient to sustain a robust economy with distinct economic roles.   Thus: Every morning while some natives would go off to hunt and gather, others would stay behind to make tools, scrape hides or just squat on the choicest camping spots. Come evening, trading would ensue.  Fruit, nuts, and game would be traded for tools and clothes and choice campsites close to the fire.

These transactions were tricky because the natives had no institutions of promising or contracting. As I said the native language did not even include words for "promise" or "debt".  If you handed over your piece of fruit in the expectation that the other guy would give you a nut, and he didn't, there was nothing that you could do and no one to complain to.  Any attempt to forcefully get your fruit back would be treated as bullying and others might forcefully restrain you.  No blame or penalty was associated with frustrating others expectations in this way.  

This made trading complicated, but not impossible. Typical exchanges among the natives would involve either perfectly synchronized handings-over or complicated dances in which the parties would set down their goods at some distance away then slowly circle round till they had traded places and possessions.  

If you wanted a squatter to yield you a choice camp site, you might place a tempting tidbit just out of his reach, so he would have to vacate his ground to retrieve it.  If you misjudged your timing and he or someone else got to the site before you, you were out of luck. No bullying!

Cumbersome though it was, the system worked. The artisans and squatters were fed and hunters and gatherers were equipped, clothed and usually slept where they might wish. The property thus traded was property because of The Rule. And thanks to The Rule the trades were always voluntary and usually accomplished to the satisfaction of all parties involved. No one was bullied into giving up their property.

But again I fear I am making the natives sound too pacific, an impression I may correct by pointing out one more wrinkle in the natives understanding of The Rule : It was not counted as bullying to use violence against someone who had given you permission to do so.

Why, you might ask, would anyone give their permission to be hurt? Well one reason (we will soon find others) was simply recreation: It provided a way for the stronger tribesmen to exercise their violent impulses without bullying.

Typically, these permissions to mutual harm would be exchanged reciprocally in an ancient ceremony.  It would begin when one tribesman saw another he thought a worthy opponent.  He would catch his eye and ask the ritual question,  "Who are you looking at?" By which was meant, "Do I have permission to do you as much violence as I possibly can?" If the other tribesman were disinclined to fight he would say, "Can't we all just get along?", and slink away.  But if he was up for it he would give the customary reply, "You want a piece of me"? By which was meant "I herewith grant you said permission provided you will grant me leave to beat you senseless".  To which the expected retort was "Bring it! " ; meaning "I do herewith grant you said permission!"  

At this point the witnesses-- and there was always an audience -- would signal to the combatants that they recognized that reciprocal permissions had been exchanged by loudly chanting "Get it on! Get it on!", by which they conveyed to one and all that, until the permissions were rescinded, they would not regard anything one combatant might do to the other as bullying.  

Thus reassured that their fight would not be interrupted, battle would commence. At any point in what followed either party could rescind his permission by saying the ritual word "Uncle".  To attack a man after he had said "Uncle!" was regarded as bullying, and hence subject to violent interference from members of the audience.  This, of course, is one of the reasons the fighters would take care to make sure there was an audience and, if possible, one in which both fighters had allies.  Another reason was to protect a fighter from a poor loser's later denying that he had given permission and denouncing the winner as a bully.

In this quaint fashion the tribe survived for many years. Though, as economists might have predicted, it did not prosper or progress as much as it might have.  No native craftsman would labor very long over a spear that anyone might walk off with as soon as he or she set it down.  And no one bothered to hunt or gather for more food than they could immediately eat or barter away.  So the natives' tools remained primitive and their stores of food so small that a hard winter or drought could lead to general famine.  Life was short, but, thanks to The Rule, not as nasty or as brutish as it might have been.

Then one day disaster struck...

Trolley Problems

You've heard this one before:

TROLLEY
A runaway trolley is coming down the track. It is headed towards five people who cannot get out of its way. A Passerby realizes that he can save the five by throwing a switch and diverting the trolley down a siding, but he also realizes that if he does so, the trolley will kill a Lone Man standing on the siding.

Should you divert the trolley? Lots of folks say, "Yes!" Whether or not they are right is an interesting problem but it is not what philosophers call "The Trolley Problem". That problem involves a different case:

FAT MAN
A runaway trolley is coming down the track. It is headed towards five people who cannot get out of its way. A passerby realizes that if he pushes a nearby fat man onto the tracks his bulk will stop the trolley before it hits the five, though the fat man himself will be killed.

Most people, including those who think it is okay to turn in TROLLEY, think that it is not okay to push the FAT MAN. "The Trolley Problem" is how to reconcile these two answers. In both cases it seems you can do something that will save five people but only by killing one. How can anyone think it okay to turn in TROLLEY but wrong to push the FAT MAN? What difference is there between the two stories that can possibly make a moral difference?

In the almost forty years since Judith Jarvis Thomson first posed the problem in this form there have many attempts to solve it but none is generally accepted as successful. Indeed a general consensus seems to have developed that the "folk intuitions" (as philosophers call them) about the difference between these cases are simply irrational.

Thus a Utilitarian like Peter Unger can argue that, since there is no difference, it must be morally okay to go around doing things like pushing fat men under trolleys so long as it promotes the general happiness.

Meanwhile Judith Jarvis Thomson concludes that, since there is no difference between the cases, it must be wrong to turn in TROLLEY and so FAT MAN represents a reductio ad absurdum of Utilitarianism.

Both sides explain away "folk intuitions" that the cases are somehow different as a psychological aberration. Folks feel better about killing other folks in TROLLEY-- this theory goes-- because they are more comfortable with throwing a remote switch in TROLLEY than they are with the up close shoving that FAT MAN requires. There are even psychological "experiments" and (God help us) neural imaging studies that are supposed to explain (away) these folksy confusions.

In a conflict between folk intuitions and philosophical theory I'll bet on the folk every time. In this post, I'm not going to take a position on whether or not it is permissible to turn in TROLLEY or push the FAT MAN. My goal instead is to show that, as described, there are subtle but important differences between the FAT MAN and TROLLEY cases; differences that can make a moral difference in other circumstances, but differences that have, hitherto, gone overlooked by philosophers.

We begin with some different thought experiments.

SACRIFICING OTHERS
A runaway trolley is coming down the track. It is headed towards a Lone Man on the tracks who cannot get out of the way. However that man is standing by a switch which, if thrown, will divert the trolley down a siding. In that case the man will be safe but he can also see that, in that case, five people standing on the siding will be killed.

Is it morally permissible for the man to throw the switch? If it is permissible, what of this:

SHIELDING ONESELF
A man sees that someone is about to shoot him. To protect himself, he grabs an innocent bystander and uses her as a shield.

Now there is a line of thought that says that when one's life is in danger, anything goes. The philosopher Hobbes seems to have held something like this position. But this seems to me to throw morality out the window when it may be most required. It seems to me that SHIELDING ONESELF and SACRIFICING OTHERS are clearly impermissible and in what follows I'm going to assume you agree with me.

Now consider.

SELF DEFENSE
A runaway trolley is coming down the track. Luckily there is no one in its path. A passerby, Burns, sees this but he also notices that Homer, someone he hates, is standing on a siding. Burns realizes that if he throws a nearby switch, the trolley will be diverted down the siding killing Homer. Homer can see all this too and when he sees Burns moving towards the switch he correctly guesses his intent. Homer cannot get out of the way but he is not defenseless: he has a gun. He draws it and shouts "Stop or I'll shoot!". But Burns ignores him and keeps moving the switch.

Assuming all these facts, I expect you to agree with me that it would be morally permissible for Homer to pull the trigger. It seems an ordinary case of self-defense albeit against an unusual attack.

Now for the interesting case:

Self Defense

If we have any rights, we surely have the right to self-defense. And yet self-defense has proven very puzzling to Rights theorists. To see why, take a simple case:

VILLAINOUS AGGRESSOR
There are two agents, AGGRESSOR and VICTIM: AGGRESSOR resents VICTIM for his sauve good looks and skill on the dance floor and has made it clear that he intends to kill him. One day AGGRESSOR shows up at the dance hall, gun in hand. He takes a shot at VICTIM but misses narrowly. He prepares to fire again, taking more careful aim, but VICTIM too has a gun and his only hope of surviving is to return fire and kill or disable AGGRESSOR.

Is it morally permissible for Victim to shoot aggressor? Of course! But now here's the puzzle. Rights Theorists have wanted to say:

1. It is permissible for VICTIM to shoot AGGRESSOR because VICTIM has the right to self-defense.
2. VICTIM has the right to self-defense because he, like everyone, has the right not to be killed or harmed. (That is why, if you are attempting to kill or harm him, you are doing something wrong.)
3. In defending himself, VICTIM will kill or harm the AGGRESSOR.
4. If the AGGRESSOR, had a right not to be killed or harmed, then it would be impermissible to kill or harm him.

The puzzle is: what happened to AGGRESSOR’s right not to be harmed?

It seems we must say that, by launching his attack, the attacker somehow loses his right not to be harmed. But where does it go?

Note that wherever it goes it doesn't go very far: Suppose that AGGRESSOR takes his second shot and his defective gun explodes rendering it useless and leaving him wounded and helpless on the ground. AGGRESSOR is no longer a threat and now most people (well, anyway, most philosophers) think it would be wrong for VICTIM to draw his gun and execute the now helpless AGGRESSOR. Apparently, AGGRESSORs right against being harmed returns as soon as he is no longer a threat to VICTIM’s life.

And yet there must be more to AGGRESSOR’s losing his right against harm than his just being a threat. After all as soon as any victim decides to defend himself against any aggressor he becomes a threat to that aggressor but we don't want to say that deprives a defender of any rights.

So maybe we should say that the AGGRESSOR's right not to be harmed doesn't go away at all? Couldn't we say that while AGGRESSOR retains his right not to be killed, VICTIM’s right to self-defense is more stringent or weighty than a simple right not to be killed and so it overrides or trumps the AGGRESSOR's right?

But that doesn't seem right either. Even acting in self-defense you have to respect some people’s right not to be harmed. Thus it would not be permissible for VICTIM to defend himself by grabbing some innocent bystander and use him as a shield against AGGRESSOR's bullet. The bystander’s right not to be harmed is not trumped or overridden by VICTIM’s right to defend himself.

So it must be something specific to the AGGRESSOR that removes, diminishes or discounts his right against being harmed; something that distinguishes AGGRESSOR from the bystander. But what can that be?

Isn't the answer obvious? AGGRESSOR, unlike the bystander, is a bad guy. He is trying to do something morally impermissible and for that reason he forfeits his claims against others harming him.

Alas, this collides with the problem of "innocent threats". Two examples from the literature:

FALLING MAN
Out for a walk one day, this man was swept up by a tornado. Now he is plummeting towards earth. When he strikes he will fall directly on VICTIM.  With VICTIM's body cushioning his fall the FALLING MAN may survive but VICTIM will certainly be killed. VICTIM cannot get out of the way, but is carrying a ray gun which he can use to vaporize the falling man and save himself. *

HUMAN SHIELD
An enemy has sent an automated tank on its way to kill VICTIM. VICTIM has an anti-tank gun and can destroy the tank. To discourage this, the aggressor has strapped an innocent passerby to the front of the tank to act as a human shield. Victim can save himself only by killing this person. *

In both these cases most people would say that it is morally permissible for VICTIM to defend himself even though, regrettably, this would result in the death of an innocent person. And by "most people", I do not mean just "most philosophers" or "most undergraduates when given questionnaires". I mean that it is the nearly unanimous opinion of all mankind, in virtually every human society of which we are aware, in every legal system ever devised, that this is so. No court-- not now, not ever-- would hold VICTIM guilty of wrongful killing if he defended himself in these situations. No work of literature or drama has or would treat a victim’s refusal to defend himself in such circumstances as anything less than heroic; that is, as a sacrifice beyond the call of moral duty.

All of which seems to leave the right theorists with a choice of bullets to bite.

Judith Jarvis Thomson and Frances Kamm conclude that, given that it is permissible to kill innocent threats, we just have to say that that FALLING MAN and HUMAN SHIELD, because they are threatening VICTIM’s life, have forfeited their rights not to be harmed no less that the villainous AGGRESSOR, albeit through no fault of their own.

This seems odd and, again, opposed to common sense. No jury-- not now, not ever-- would convict these innocent threats of any crime were the Victim to be killed. The Shield and the Falling Man do not choose to cause death Yes, VICTIM’s death would be a bad thing, but it wouldn't be their fault any more than it would be a bystander’s fault. How can their actions, if they can even be called that, represent a forfeiture of their rights?

But then what is the alternative?

Now, Me

My topic is the state of mind of people who utter sentences containing indexicals; sentences like "I am here now".    It is a subject much discussed in recent years but invariably it has been addressed as an issue in philosophical semantics: as a problem about what indexical words mean.  I want here to pursue a different and, I hope, more productive approach ....     (...with a new way of doing epistemology in the bargain.)

The Retributive Theory of Property

Property rights are collections of rights. In the first place: for something to be your property you must have the right to use or enjoy that thing. In the second place, you must have rights of control: rights that others not use or enjoy that thing in certain ways, except by your permission. Thirdly, though perhaps not necessarily, you must have the right to transfer the former two rights to someone else (as when you give your property to someone else) and fourthly the right to some form of compensation should someone infringe the preceding rights. Each of these rights, moreover, might be divided and limited in various ways. You may have the right that others not walk on your property, but not that others refrain from burrowing underneath it or flying over it. You may have a right to cultivate your own garden, but not to grow opium therein.

And so on. Acknowledging all this complexity, let us set it aside for now and focus on clear cases of the least complicated sort. I have an apple in my hand. I may eat if I choose, use it to make a pie or cider or let it rot. I may give it to someone else. You may not eat my apple without my permission. If you do so, you will have done something wrong and you will owe me compensation. All this because the apple is mine.

What are property rights? Where do they come from?

According to Retributive Ethics, moral rights are merely warrants for violence. All rights are Retributive rights: rights to harm other people. So when a Retributivist hears a right asserted he asks only who is claiming a moral permission to hurt whom, by how much and when.

In the case of property rights the question has clear answers: property rights at least include rights to defend your property: that is, to do harm to those who attempt to deprive you of its use and the right to forcibly interfere with others if they should attempt to use it without your permission. You may interfere with them by building fences or locking doors or by putting your body in their path. Should push come to shove, you may push and shove or, if society recognizes your property claim, you may call on the cops, who will do the pushing and shoving and, if need be, shooting on your behalf.

You are in short, entitled to enforce your property rights. "Force" being the operative word.

Now, academics are apt to grow faint at the first mention of violence so let me quickly offer some palliating remarks for tenured readers. Note first of all that acknowledging a right to defend property does not require you to think property rights warrant absolutely any degree of violence in the defense of absolutely any property. You may not think it permissible to shoot a burglar if you do not have much worth stealing or even if you do. You may yourself be so passive or pacifist that you would not lift a finger to protect your belongings. You may be so empathetic to the plight of those driven by circumstance to theft that you wouldn't even call the cops. Never mind. What matters is that you agree that having property makes it sometimes morally permissible (however personally repugnant) to forcibly interfere with others in some ways that would not be permissible if you had none. To deny this-- to say that it is always morally impermissible to lock a door, build a fence, or lift a finger (even to dial '911')… to defend one's property seems to me to simply deny that there is any moral right to property.

Note too that acknowledging the right to enforce your property claims does not presuppose that property rights, or any other rights, are in any sense "natural". Even if you think that the rules that govern property acquisition and ownership are as arbitrary a social artifact as the rules of NFL Football, you must nevertheless recognize that our adoption of those rules makes certain kinds of violence permissible. Neither the lineman who tackles the quarterback nor the cop who tackles the purse thief is doing something morally wrong. So even if you think "the possession of property under the law" is as inherently amoral a notion as "possession of the ball in football", you must have some account of how the violence of the lineman and the cop come to be morally permissible.

If we agree that property rights at least include some kinds of permissions to use force the next question is whether they include anything more.

Retributive Ethics in a Nutshell

Retributivist Ethics is rooted in five assumptions. 

The first is that something of the following form is true: 

     (1) x is Morally permissible = x harms no one or R₁x , or R₂x, …R_nx. 

Where x ranges over actions. 

The second assumption is that there are properties answering to R₁… R_n and actions which satisfy them.  That is, that there are some features of some actions which make them morally permissible even though those actions do cause harm to others.  

The third is that it is possible to describe what constitutes harming someone in non moral terms.

The fourth is that is also possible to describe those R-properties-- those circumstances which harming others is permissible -- in non-moral terms. 

The third and fourth assumption make Retributivism a reductive thesis.  Note that "=" in (1) expresses an identity on a par with:

    (2)        X is water = x is H2O . 

Retributivism is not a thesis about "the meanings" of moral terms-- whatever "the meanings" might be.  It is a thesis about what moral permissibility is.  It aims to say that to do something morally wrong just is to do one of those things that harms another and is not R₁… or R_n,  just as (2) says that to be water just is to be two parts hydrogen and one part Oxygen. 

Finally, Retributivism is the assumption that all of ethics, everything worth saying about moral right and wrong, will have been exhausted when we have spelt out (1) .  

Spelling out the R's -- saying when it is permissible to harm another--  is a matter of describing agents moral rights and claims.  

Thus, it is permissible to harm another if one acts in self-defense, so we may speak of the "right of self defense". 

To say that someone X has a moral  claim against someone Y that Y do something A (e.g. because Y has promised X that Y will do A) is to say that it would be permissible in certain circumstances for X to harm Y in certain ways (e.g. to force Y to keep his promise).  

To say that someone X has right to compensation from Y because of some harm Y has done X is to say that X has a right to force Y to perform some compensating act. 

Note the Retributivist may not say that the right of self defense makes it permissible to use force in a certain way.  Nor may he explain the permissibility by appealing to the right.  His thesis is that the right is the permission.  On the other hand the Retributivist need not argue for the existence of any right beyond the permissions it entrains.  Once it is conceded that the relevant harmings are permissible then the Retributive right has been wholly established. 

I distinguish between causing harm to others and allowing harm to come to others and assume that absent prior promises the latter are always permissible.  One might revise this assumption, including at least certain kinds of allowing to harm as impermissible and still call oneself a Retributivist if one accepted the other premises.