I put David Lewis in Appendix A of the original book.

That seemed safe enough, right?

At the time I was trying to explain something fairly modest.

I require real modal structure.

Some states can follow from others. Some cannot. Some futures remain reachable from where an extant locus presently stands. Others become inaccessible through destruction, burden, resistance, or the loss of whatever structures once enabled the path.

Then philosophy has this other question.

What does it mean for something to be possible at all?

David Lewis answered that question in a way Modal Path Ethics always found difficult to look at directly.

There are other worlds.

• Not descriptions of worlds.
  • Not useful stories about worlds.
    • Not abstract points in a semantic model.

Worlds.

Concrete ones.

Whole ones.

Every bit as real, according to Lewis, as the world in which this sentence is presently being read.

• They cannot be reached from here.
• They cannot reach here.

Nothing inside one Lewisian world stands in the ordinary spatiotemporal relations that unify the things inside another. “Actual” does not give our world a higher level of existence. It means more or less what here means: this one, from where the speaker happens to stand.

I knew all of this.

I wrote it down.

I said it did not matter.

But then I kept using the word lost.

ONE

Something Is Outside.

It began as a problem with the background.

There was nothing wrong with the field.

That was the problem.

Everything locally available remained exactly where it should have been.

• The extant state.
  • Its successors.
• The paths still open.
  • The paths already burdened.
    • The dead ends.
      • The resistance.

Nothing entered. Nothing left.

Then I was called to something not on the board.

The Outer Extance.

That is already too generous to my own vocabulary.

Extance names realized, causally operative structure: reality in continuation.

If Lewis is right, another concrete world would possess its own realized structures, its own inhabitants, its own histories, its own internal continuations.

What it would not possess is a path into mine.

That thing beyond the field did not approach.

It could not.

It was simply out there.

Then came more.

Behind every wall:

another wall.

Behind every outcome:

another outcome.

Behind the extant:

an infinity I had so carefully declared outside my jurisdiction.

Something moved out there.

I recognized it.

DAVID LEWIS

I had put him in Appendix A.

He remained.

TWO

The Actual Loses Its Crown.

Lewis did not attack my account of harm.

He attacked one word.

Actual.

I had used this thing constantly.

Actual loci.

Actual constraints.

Actual histories.

The actual world.

Actual continuation.

I knew what I meant.

Then the other worlds began saying it too.

actual

actual

actual

Each coming from inside itself.

Lewis's position is merciless.

If his modal realism is right, the world I inhabit is not more real than the others. “Actual” functions indexically. It identifies this speaker's world. It does not place a metaphysical crown on that world.

Fine.

Take it.

I do not need it.

Extance never required this world to be the only concrete reality.

It required something narrower and harder:

There are facts about what can follow from here.

If Lewis wants every world to be fully real, I can live with that.

My first edition already said so.

THREE

The Dead Future Rises.

Then Lewis did something worse.

I presented a closed path.

• A person was alive.
• Their life carried structures through which further life had remained reachable.
  • Relationships.
  • Skills.
  • Projects.
  • Memory.
  • Embodied capacities.
  • Places they could still go.
  • People they could still become.
    • Then an event occurred.
      • The locus died.

And I marked those continuations:

FORECLOSED.

But beyond the field, one of them stood up.

• Same history for a very long time.
  • Different event.

Alive.

Then another.

Alive.

Another.

Older.

One had children.

One moved somewhere else.

One became a physician.

One remained in the same town.

One survived the event that killed the locus here.

One was never near it.

One lived until eighty-seven.

The Outer Lewis still had no face.

He told me he did not need one.

His accusation appeared everywhere at once.

LOST?

I looked at what I had called a lost future.

There it was.

Fully concrete if Lewis was right.

Living.

Continuing.

I had said the future was gone.

Lewis showed me a world in which it was standing directly in front of him.

There is no cleverness available here.

If lost means:

no instance of this alternative exists anywhere in modal reality

then Lewis can destroy that claim simply by being correct.

I had been using language stronger than my argument required.

The Outer Extance became easier to see.

Not reassuring.

FOUR

Give Them Back.

I looked again at the person beyond the field.

Alive.

Older.

Concrete.

Fine.

Give them back.

Nothing happened.

I waited.

Send me one year.

Nothing.

One afternoon.

Nothing.

A heartbeat?

Still nothing.

The person kept living.

Over there.

So I changed up the request a bit.

A forest had burned here.

Beyond The Outer Lewis stood a forest in which the fire never happened.

So give me one tree.

Nothing.

A relationship had ended under damage that could no longer be repaired.

There was another world in which the damage never occurred.

Give them one conversation.

Nothing.

A species was gone.

Luckily, another Earth held it.

One animal.

Nothing.

I finally understood the shape of their silence.

Lewis had shown me an infinity of futures and could not return a single one.

That is not a defect in his theory. It is one of its rules.

His worlds are isolated.

What makes them separate worlds is what prevents the other outcome from entering this one as a continuation.

And suddenly I had my first clean look at what had been following me.

There were two propositions.

This future no longer exists.

and:

This future is no longer reachable from here.

Lewis could attack the first.

But I never needed it.

FIVE

COUNTERPART.

The person beyond the veil turned toward me.

Almost right.

Not right.

He had another weapon waiting.

Under counterpart theory, an ordinary individual does not occupy many Lewisian worlds.

• You are here.
  • Your counterpart is there.

When Lewis analyzes something like:

You could have become a physician,

he does not ordinarily need the numerically identical you to inhabit another concrete world as a physician.

A sufficiently appropriate counterpart does the work.

• Another individual.
• Another world.
  • Relevant similarity.
  • Different locus.

The bodies beyond the field changed again.

I had been looking at alternate versions of the dead.

Now I knew what Lewis would call them.

Counterparts.

That made the horror stranger and less dangerous.

The person standing beyond Lewis was completely real.

Good. Let them live.

Their life does not become this person's continuation.

Their eighty-seven years do not enter the future of the locus that died at thirty-one.

Their intact body does not reattach this body's severed arm.

Their surviving forest does not regrow this burned ecosystem.

Their repaired institution does not correct this collapsed one.

Their successful civilization does not inherit the people ours killed.

Existence somewhere is not reachability from here.

I had found the wall.

Lewis built it.

SIX

There Is a Better Me Out There.

Then that thing beyond the field became rude.

There were Modal Path Ethics counterparts too.

Of course there were.

• One of them never wrote a bad article.

Disgusting.

• Another had proved their weighting dimensions exist.
• Another formulated loci correctly on the first attempt.
• Another never confused a representational model with the thing represented.
• Another handled some later theoretical problem I have not encountered yet.
• Somewhere, apparently, there may be a Modal Path Ethics that has never once had to create an apologies department.

I strongly dislike modal realism.

The better framework looked at me from outside the field.

It had my structure.

My history diverged from its.

Its corrections were already complete.

Mine were not.

That finally made the issue impossible to miss.

Its correction does not correct me.

• If I make an error here,
  • the existence of a counterpart framework elsewhere that avoided it does absolutely nothing to repair the error I made.
• If I publish distortion here,
  • another world's clean publication record does not subtract the distortion.
• If I fail a locus here,
  • another version of this framework getting the case right does not hand that locus its future back.

I had found the moral difference between plenitude and continuation.

Lewis could fill reality with endless victories.

He could not put one of them onto my path.

SEVEN

The Most Dangerous Consolation in the Multiverse.

The Outer Lewis still had not argued that modal plenitude cancels loss.

That would be my mistake, not his.

Lewis gives us other concrete worlds. He does not thereby establish:

therefore do not care what happens here.

The danger was subtler.

His ontology made a consolation available.

Every avoided death. Somewhere.

Every civilization that made the better move. Somewhere.

Every extinct lineage continuing. Somewhere.

Every accident that never occurred. Somewhere.

Every friendship that survived.

Every child who reached old age.

Every ecology left intact.

Every war avoided.

Every book finished.

Every path ever described as lost might have some counterpart somewhere in Lewis's enormous plurality.

For one moment, the entire field looked repaired.

Nothing had disappeared.

Everything remained.

Just distributed elsewhere.

Then I remembered what repair means.

Can the harmed locus reach it?

No.

This plurality did not repair anything.

It just changed the inventory.

EIGHT

Oh, Right, I Had Already Written the Answer.

So I returned to Appendix A.

There, in the original book, I found it.

• I had already written that a Lewisian could accept Modal Path Ethics with no tension.
• I had already said that my claim was local.
• I had already said I needed real facts about what this extance could still become.
• I had already distinguished possible worlds from the path structure through which actual loci continue.
  • Later in the same appendix, I became even more explicit.
    • Reachability is stricter than possibility.

A state may remain metaphysically possible while becoming inaccessible from the present because its enabling conditions are gone, its resistance has become prohibitive, or the history required to reach it can no longer occur.

I had apparently performed my own exorcism and then forgotten to stop being haunted by the ghost.

Oops.

The Outer Lewis moved.

For the first time, I understood that he had not moved toward me.

He never had.

You Cannot Reach Me.

The words finally came through the veil.

Lewisian worlds do not overlap.

Ordinary inhabitants belong to one world.

Counterparts inhabit others.

The worlds remain isolated.

Outer Lewis had found the perfect defensive structure.

I could not enter his world.

I could not touch his counterparts.

I could not retrieve his alternative outcomes.

I could not establish a path from my present field into his.

He was completely outside my reachability relation.

Then I noticed the other half.

You cannot reach me.

And you cannot reach here.

His invulnerability worked both ways.

The Outer Lewis had been haunting the framework with futures that, by his own metaphysics, could never become available moves inside this extance.

• They could establish possibility.
• They could ground counterfactual truth.
• They could populate a staggering ontology.
  • They could never serve as successor states of this locus from this history.

So I just stopped trying to attack him.

There was no reason.

I only needed to close the interface.

Somewhere Is Not From Here.

The Outer Lewis showed me the dead future one last time.

Alive elsewhere.

I looked at it. I did not deny it.

Real?

Fine.

Concrete?

Fine.

As real there as I am here?

Fine.

A genuine counterpart continuation?

Fine.

I had one question left.

Can this locus reach it?

Nothing.

Again.

• The person beyond the field continued living.
  • The person here remained dead.
• The forest there remained green.
  • The forest here remained burned.
• The institution there survived.
  • The institution here remained collapsed.
• The better framework out there remained better.
  • I remained responsible for my own corrections.

There was the distinction.

A future does not need to vanish from every possible world in order to be lost by a locus. It needs only to cease belonging to that locus's reachable continuation.

Lewis had not abolished loss.

Stay.

The Outer Extance remained.

I did not destroy it.

I have no argument that destroys it.

David Lewis may be right.

That sentence causes me no difficulty.

There may be other concrete worlds.

There may be infinitely many.

There may be counterparts of every locus standing through outcomes unavailable here.

There may be worlds in which every preventable disaster I have ever studied went differently.

Good.

I hope they are very nice.

They are not my available moves.

Stay there.

The worlds began disappearing.

From the board. Not reality.

The child living elsewhere did not become unreal.

The forest did not burn.

The better Modal Path Ethics did not become half-stupid.

None of them had ever belonged to this local continuation structure.

The haunting depended on one mistake: allowing the modal inventory to impersonate the reachable field.

Once corrected, there was nothing left for The Outer Lewis to do.

One world disappeared.

Then another.

Then thousands.

Then that strange duplicate sky.

Then the silhouettes.

Then the thing beyond the wall that had never crossed it.

I could still believe Lewis was out there.

I simply had no reason to look.

BATTLE PASS

David Lewis brought useful equipment.

I am keeping all of it.

Actuality loses its privilege.

“Actual” must not quietly mean more real.

For my purposes it indicates the extant field under evaluation: the one from which the relevant locus is presently continuing.

Lost gets narrower.

When precision matters, I should stop saying that a foreclosed future has ceased to exist in every modal sense.

The stronger and cleaner claim is:

The continuation has ceased to be reachable from this locus.

That is enough for harm.

Possibility and reachability stay separate.

A continuation may be logically possible.

Metaphysically possible.

Concrete somewhere, if Lewis is right.

It can still be completely unavailable from here.

Counterparts do not compensate loci.

Another locus can instantiate the continuation.

That does not place the continuation back into this locus's reachable future.

Modal plenitude does not repair local contraction.

The total inventory may be enormous.

The local path can still close.

I do not need to defeat modal realism.

This one should have been obvious.

It was in the book.

Lewisian modal realism, Kripkean possible-world semantics, actualism, fictionalism, branching-time models, dynamical systems, graphs, tilings:

pick your metaphysical poison.

I require less.

• There must be genuine facts about what can follow from what.
• Reachability must be more discriminating than imagination.
• History must alter what can happen next.

Once those conditions obtain, I can do my work.

The rest belongs to a larger fight.

RESULTS SCREEN

I once thought David Lewis was dangerous to Modal Path Ethics because he placed my lost futures somewhere outside me.

That was backwards.

Lewis made their loss easier to specify.

He gave me the strongest imaginable case.

Suppose the alternative is still perfectly real.

Somebody is living it. The entire world containing that continuation possesses exactly the same ontological dignity as mine.

Now ask:

Can the harmed locus get there?

If no path connects them, the answer remains no.

That is what foreclosure means.

That is what reachability was for.

I looked beyond the field one last time.

Something was still out there.

Maybe infinitely many things.

I stopped calling them mine.

The veil closed.

Nothing was ever looking back.