Complexity and the Metaphysics of Time

Complexity
and the Metaphysics of Time
Variations on the Future Perfect
Jean-Pierre Dupuy
[email protected]
Complexity Group, Stanford, February 13, 2013
The Stanford Complexity Group Presents:
Jean-­Pierre Dupuy
Stanford University and Ecole Polytechnique, Paris
Complexity and
the Metaphysics of Time
Wednesday, February 13th, 4:15pm
Building 260 (Pigott Hall), Room 113 More info at complexity.stanford.edu
6DOYDGRU'DOt´:RXQGHG6RIW:DWFKµ
Apocalyptic Bibliography
Pour un catastrophisme éclairé
(Paris, Seuil, 2002, 2004)
La Panique (Paris, Les Empêcheurs de
penser en rond, 2003)
Avions-nous oublié le mal?
Penser la politique après le
11 septembre (Paris, Bayard,
2002)
Petite métaphysique des
tsunamis (Paris, Seuil, 2005)
Retour de Tchernobyl: Journal
d'un homme en colère (Paris,
Seuil, 2006)
La Marque du sacré (Paris, Carnets
Nord, 2009)
L’Avenir de l’économie ( Paris,
Flammarion, 2012)
Penser l’arme nucléaire (Paris,
PUF, 2013)
1. Prologue
Essential Monism
The World
We
Dualism
Action
Leibniz-Descartes
The world
We
Representation
Actions
Prices
Agents
Reactions
Actions
Future
Agents
Anticipation
Isn’t the future open, like a
branching tree?
Future generations may well
have occasion to ask
themselves «What were our
parents thinking? Why didn t
they wake up when they had
a chance?»
We have to hear that
question from them, now.
Al Gore
Hans Jonas (1903-1993)
“What can serve as a compass?
The anticipation of the threat
itself! It is only in the first
glimmer of its tumult that comes
to us from the future, in the dawn
of its planetary scope and in the
depth of its human implications,
that we can discover the ethical
principles from which the new
obligations corresponding to our
new power can be deduced.”
The Imperative of Responsibility,
In Search of an Ethics for the
Technological Age, 1985.
Changing the Future?
"What we can do by way of 'changing
the future' (so to speak) is to bring it
about that the future is the way it
actually will be, rather than any of
the other ways it would have been if
we acted differently in the present.
That is something like change. We
make a difference. But it is not
literally change, since the difference
we make is between actuality and
other possibilities, not between
successive actualities. The literal
truth is just that the future depends
counterfactually on the present. It
depends, partly, on what we do now.”
David K. Lewis, "Counterfactual
Dependence and Time's Arrow,” 1986.
"Cleopatra's nose, had it been shorter, the whole
face of the world would have been changed.
Pascal, Pensées, 1660
One would like to say things such as: "Had Cleopatra's nose been
shorter, Mark Antony wouldn't have fallen in love with her, and the
history of the Roman Empire would have been radically different from
what it turned out to be. --> Counterfactual (or Virtual) History.
Counterfactual Conditionals
vs Indicative Conditionals
A: If Shakespeare didn’t write The Winter Tale, [then]
someone else did.
B: If Shakespeare had not written The Winter Tale, [then]
someone else would have written it.
A true.
B probably wrong.
The Vagueness of Counterfactual
Conditionals
David: “Did you know? Our colleague Peter has
renounced buying a house in the Marina.”
Max: “If he had, he would be broke.”
B
© Not R
John: “If he had, he would be very rich.”
B
©R
John’s proposition is a backtracking counterfactual
conditional.
B = Buy
R = Rich
A choice between two different
metaphysics
Causalism: A©B iff A causes B,
where A©B means: if A were true, B would be true.
Violations of Causalism
Counterfactual Power over the Past
The Future as counterfactually independent of the present
action (“fixed future”)
Counterfactual Power Over the Past
Béatrice de Toledo Dupuy
“If I had decided to delay
my trip by one day,
the crash would not have
happened that day.”
June 2, 2009
AF 447, June 1, 2009
Counterfactual Power over the Past
“He could no longer hide his
excitement, the importance he
attached to this encounter, and
he promised in the event of
success to bestow a reward on his
coachman, as if, by inspiring in
him a desire to succeed that
would be added to the one within
himself, he could so act that
Odette, in case she had already
gone home to bed, would
nevertheless be found in a
restaurant on the boulevard.”
Marcel Proust, Un amour de
Swann
2. Non-Causalist
Metaphysics of Time
A Critique of the Scenario Approach
•  Gaston Berger and the
concept of Prospective.
•  Bertrand de Jouvenel and
the concept of Futuribles.
There can be no science
of the future. The future
is not the realm of the
'true or false' but the
realm of 'possibles.
•  This approach deprives
the future of all reality.
Confusing ontological indeterminacy
with epistemic uncertainty
All who claim to foretell or forecast the future are inevitably
liars, for the future is not written anywhere – it is still to be
built. This is fortunate, for without this uncertainty, human
activity would lose its degree of freedom and its meaning – the
hope of a desired future. If the future were totally
foreseeable and certain, the present would become unlivable.
Certainty is death. Because the future has to be built, it also
cannot be conceived as a simple continuation of the past.
Michel Godet, "Creating the future: the use and misuse
of scenarios", Long Range Planning, 29, 2, 1996.
Unbestimmheitsrelation
Isn t the past also ontologically
indeterminate?
There is no privileged past (...) There is an infinitude of Pasts, all
equally valid (...) At each and every instant of Time, however brief
you suppose it, the line of events forks like the stem of a tree
putting forth twin branches.
French historian André Maurois,
quoted by Niall Ferguson in his Virtual History
The historian must (...) constantly put himself at a point in the
past at which the known factors will seem to permit different
outcomes. If he speaks of Salamis, then it must be as if the
Persians might still win; if he speaks of the coup d'Etat of
Brumaire, then it must remain to be seen if Bonaparte will be
ignominiously repulsed.
Dutch historian Johan Huizinga
Is Counterfactual History a mere "parlour game"
or "red herring ?
It is possible that had St Paul been captured and killed
when his friends lowered him from the walls of Damascus,
the Christian religion might never have become the centre of
our civilisation. And on that account, the spread of
Christianity might be attributed to St Paul's escape ... But
when events are treated in this manner, they cease at once
to be historical events. The result is not merely bad or
doubtful history, but the complete rejection of history
(...) The distinction (...) between essential and incidental
events does not belong to historical thought at all.
Michael Oakeshott, Experience and its Modes ,
Cambridge, 1933.
The parties to the debate about the meaning of
virtual history appear to suffer from symmetrical
blind spots.
•  The "What if?" historians argue as if the
possibilities that did not become actual kept
existing forever, in a kind of eternal limbo.
•  The mainstream historians who refuse to ascribe
any meaning to counterfactuals reason as if agents
endowed with free will didn't make any difference
in the way events occur.
•  Is it possible to transcend this opposition?
Henri Bergson
Le possible et le réel, 1930
"Je crois qu'on finira par
trouver évident que l'artiste
crée du possible en même
temps que du réel quand il
exécute son œuvre. »
I believe it will ultimately be
thought obvious that the
artist creates the possible at
the same time as the real
when he brings his work into
being.
Possibility is a retroactive
modality.
Picasso, Les demoiselles d’Avignon
(1907)
Henri Bergson
Le possible et le réel, 1930
“I believe it will ultimately be
thought obvious that the artist
creates the possible at the
same time as the real when he
brings his work into being.
[…]
As reality is created as
something unforeseeable and
new, its image is reflected
behind it into the indefinite
past. It turns out that it has
from all time been possible, but
it is at this precise moment that
it begins to have been always
possible, and that is why I said
that its possibility, which does
not precede its reality, will have
preceded it once the reality
has appeared.”
•  Catastrophes too are
characterized by this
temporality that is in some
sense inverted. As an event
bursting forth out of nothing,
the catastrophe becomes
possible only by
"possibilizing" itself (Sartre).
•  And that is precisely the
source of our problem. For if
one is to prevent a
catastrophe, one needs to
believe in its possibility
before it occurs. If, on the
other hand, one succeeds in
preventing it, its nonrealization maintains it in the
realm of the impossible, and
as a result, the prevention
efforts will appear useless in
retrospect.
The Precautionary Principle
in the Rio de Janeiro 1st Earth Summit Declaration (1991)
“The absence of certainties, given the
current state of scientific and technological
knowledge, must not delay the adoption of
effective and proportionate preventive
measures aimed at forestalling a risk of
grave and irreversible damage to the
environment at an economically acceptable
cost.”
Placing the emphasis on scientific uncertainty, the PP and other
current risk analyses utterly misconstrue the nature of the obstacle
that keeps us from acting in the face of catastrophe. The obstacle is
not uncertainty, scientific or otherwise; the obstacle is the
impossibility of believing that the worst is going to occur.
Henri Bergson describes what he felt on August 4, 1914, when
he learned that Germany had declared war on France: "In spite
of my shock, and my belief that a war would be a catastrophe
even in the case of victory, I felt… a kind of admiration for the
ease with which the shift from the abstract to the concrete
had taken place: who would have thought that so awe-inspiring
an eventuality could make its entrance into the real with so
little fuss? This impression of simplicity outweighed
everything." Now, this uncanny familiarity contrasted sharply
with the feelings that prevailed before the catastrophe. War
then appeared to Bergson "at one and the same time as
quasi-certain and as impossible: a complex and contradictory
idea, which persisted right up to the fateful date."
An Antidote to Bergson’s
Metaphysics
“Man is no more than
the sum
of his past
commitments.”
Jean-Paul Sartre,
L’Être et le néant,
1943
Philosophy of absolute freedom
As human beings live, they are
absolutely free, and their freedom
resides entirely in their capacity
to choose, that is, to invent their
lives.
Future-oriented counterfactual
propositions such as, "If I were to
do this, the consequences would or
might be that, and I am entirely
responsible for them, whatever
they turn out to be", make full
sense.
However, as soon as "death has
turned life into destiny",
backtracking counterfactual
propositions such as, "Had I had
more time to devote to my work, I
would have written the novel of the
century", are completely devoid of
meaning and serve as mere alibis or
cheap excuses – the stuff
”mauvaise foi" is made of.
Sartre s Theory of Modalities
Counterfactual propositions are admissible only when they are
future-oriented. When we look back at the past, we see only
necessity. There is nothing else than that which has happened,
no possibility that never came to actuality.
When history unfolds, possibilities become actual, but
something strange happens to the branches that were not
selected. It is not that they have become impossible: it turns
out that they were never possible! As history proceeds in its
course, it interjects necessity back into the past. Necessity is
only retrospective [as possibility was for Bergson.]
Giving reality to the future: project yourself into the future
and look back from there at the present. Seen from the
present the future was open, but seen from the vantage point
of the future, the path that led to it appears to have been
necessary. We were free to choose, to be sure, but what we
chose appears to have been our destiny.
Choosing one’s destiny: the Heideggerian connection
3. Why We Need
the Future
Heidegger s Children
Hans Jonas, Günther Anders, Hannah Arendt
Günther Anders
with Hannah Arendt
Günther Anders
on the Flood
Endzeit und Zeitenende:
Gedanken über die atomare
Situation, München, 1972
Mourning the Future
Noah was tired of playing the prophet of doom and of always foretelling a
catastrophe that would not occur and that no one would take seriously.
One day, he clothed himself in sackcloth and put ashes on his head. This act
was only permitted to someone lamenting the loss of his dear child or his
wife. Clothed in the habit of truth, acting sorrowful, he went back to the
city, intent on using to his advantage the curiosity, malignity and superstition
of its people. Within a short time, he had gathered around him a small
crowd, and the questions began to surface. He was asked if someone was
dead and who the dead person was. Noah answered them that many were
dead and, much to the amusement of those who were listening, that they
themselves were dead. Asked when this catastrophe had taken place, he
answered: tomorrow. Seizing this moment of attention and disarray, Noah
stood up to his full height and began to speak: the day after tomorrow, the
flood will be something that will have been. And when the flood will have
been, all that is will never have existed. When the flood will have carried
away all that is, all that will have been, it will be too late to remember, for
there will be no one left. So there will no longer be any difference between
the dead and those who weep for them. If I have come before you, it is to
reverse time, it is to weep today for tomorrow s dead. The day after
tomorrow, it will be too late.
Upon this, he went back home, took his clothes off, removed the ashes
covering his face, and went to his workshop. In the evening, a carpenter
knocked on his door and said to him: let me help you build an ark, so that
this may become false. Later, a roofer joined with them and said: it is
raining over the mountains, let me help you, so that this may become false.
The Future Perfect
“When you come to my place tonight,
I will
Yesterday
have finished
eating my dinner.”
Today
The Day After Tomorrow
Tomorrow
--------------------------------------------
Future Perfect
“Why the future doesn't need us”
Bill Joy, Wired, April 2000
Our most powerful
21st-century
technologies
- robotics, genetic
engineering, and
nanotech are threatening to
make humans an
endangered species.
It Is We Who Need the Future !
Jean-Paul Sartre, Existentialism is a Humanism (1946)
It is the future that bestows meaning
on the past
Journalist: “Can you
assess the impact of
the French
Revolution?”
Zhou Enlai: “It’s too
early to tell.”
The Meaning of the French Revolution will
Always Be in Suspense.
Thus you can understand
that our knowledge
will be entirely dead at the
moment
when the door of the
future is closed.
Dante, Hell, Tenth Canto
The day after tomorrow,
the flood will be something
that will have been. And
when the flood will have
been, all that is will never
have existed.
Günther Anders
4. The Doomsayer’s
Paradox
Towards an enlightened form
of doomsaying
The Paradox of Enlightened
Doomsaying [The Jonah Paradox]
To make the prospect of a catastrophe credible,
one must increase the ontological force of its
inscription in the future.
But to do this with too much success would be to
lose sight of the goal, which is precisely to raise
awareness and spur action so that the
catastrophe does not take place.
The prophecy of doom is made to avert its coming,
and it would be the height of injustice later to
deride the alarmists because it did not turn out
so bad after all — To have been wrong may have
been their merit.
Hans Jonas, The Imperative of
Responsibility, 1985
The Jonah Paradox
The Zadig [and Voltaire] Paradox
When Zadig sees his travel
companion the hermit murder the
nephew of their hostess of the
previous night, he is aghast.
What, he cries in outrage, could
you find no other way to thank our
hostess for her generosity than
to commit this terrible crime?
To this, the hermit, who is none
other than the angel Jesrad, the
mock spokesperson of Leibniz's
system, replies that if that young
man had lived, he would have killed
his aunt a year later and, a year
after that, he would have
murdered Zadig himself.
How do you know that? asks Zadig.
"It was written."
The Future Can Be Seen. Murder Can be
Prevented. The Guilty Punished Before the Crime
is Committed. The System is Perfect. It's Never
Wrong. Until It Comes After You.
Minority Report
Steven Spielberg, 2002
• 
Witwer: Let's not kid ourselves, we
are arresting individuals who've
broken no law.
• 
Jad: But they will.
• 
Fletcher: The commission of the
crime itself is absolute
metaphysics. The Precogs see the
future. And they're never wrong.
• 
Witwer: But it's not the future if
you stop it. Isn't that a
fundamental paradox?
• 
Anderton (alias Tom Cruise): Yes, it
is.
Minority Report in Iraq
Why is President
Bush so keen on
impersonating Tom
Cruise?
Arthur Schlesinger Jr,
March 2003
Three ways of telling the future
in human affairs
•  Prediction
•  « Prospective » [scenarios method]
•  Prophecy: The prophet, knowing that his
prophecy is going to produce causal effects
in the world, must take account of this fact
if he wants the future to confirm what he
foretold.
Two Metaphysics of
Temporality
Occurring Time
Projected Time
Preventive [war]
Preemptive [strike]
No closure condition
Closure condition
Possible
Futures
Past
Futuribles
Occurring Time
The past is fixed.
The future is open.
There exist possibles that will never occur.
“El tiempo es un
jardín de senderos
que se bifurcan.”
Jorge Luis Borges
Expectation/Reaction
Past
Future
Causal Production
Projected Time
The future is fixed.
The past is open.
The past and the future must come together in a closed loop:
the future is the fixed point of the loop.
Every possible occurs, either in the present or in the future
==> That which does not occur is impossible.
Meaning
Future
Past
Causation
Projected time
Diodorus [Kronos]
Master Argument
[4th century BC]
1. 
2. 
3. 
Every true proposition about the past is
necessary. [The past is fixed.]
The impossible does not logically follow from the
possible.
There is a possible which neither is presently
true nor will be so. [The future is open.]
1, 2, 3 are incompatible.
The Determination of the Future
in Projected Time
[Prophecy]
The secular prophet is the one who seeks out the fixed
point of the problem, the point where voluntarism
achieves the very thing that fatality dictates. The
prophecy includes itself in its own discourse; it sees
itself realizing what it announces as destiny.
The formula of the French Planning system
It aimed to obtain through consultations and research an image of
the future sufficiently optimistic to be desirable and sufficiently
credible to trigger the actions that would bring about its own
realization.
The Doomsayer s Paradox
[The Jonah Paradox]
• 
Achieving coordination on the basis of a negative project
taking the form of a fixed future which one does not
want.
• 
Obtaining through scientific futurology and a meditation
on human goals an image of the future sufficiently
catastrophic to be repulsive and sufficiently credible to
trigger the actions that would block its realization.
• 
--> Paradox of self-refutation: “it's not the future if
you stop it.”
Enlightened Doomsaying
Obtaining through scientific futurology and a
meditation on human goals an image of the future
sufficiently catastrophic to be repulsive and
sufficiently credible to trigger the actions that
would block its realization,
barring an accident.
This “accident” is the manifestation of
Unbestimmtheit in Projected Time.
How Nuclear Deterrence
works
“It is a curious paradox of our time that one of
the foremost factors making deterrence really
work and work well is the lurking fear that in
some massive confrontation crisis it may fail.
Under these circumstances one does not tempt
fate.”
Bernard Brodie, 1973
Production
FATE
ACCIDENT
Negation
Accident [Chance] as the Supplement of Fate [Necessity]
Prophecy of Doom and the Tragic
The metaphysics that must
serve as a foundation for
prudence adapted to the time
of catastrophes consists in
projecting oneself into a time
that follows the catastrophe,
and in seeing it
retrospectively as an event at
once necessary and
accidental.
It is the resulting
indeterminacy/undecidability
of the catastrophic future
that may deter us from acting
foolishly (and not the
certainty of the catastrophe.)
Chance is fused with Destiny
Oedipus
L’Etranger
Metaphysical Logic of Nuclear Deterrence
The Status of Unbestimmtheit in “Projected Time”
Not to be confused with strategic randomness: President Nixon’s
Madman Theory.
==> Nixon to Robert Haldeman (1970): "I call it the Madman
Theory, Bob. I want the North Vietnamese to believe I’ve reached
the point where I might do anything to stop the war. We’ll just slip
the word to them that, ‘for God sake, you know Nixon is obsessed
about Communism. We can’t restrain him when he’s angry – and he
has his hand on the nuclear button’ – and Ho Chi Minh himself will
be in Paris in two days begging for peace . ."
Strategic Randomness
ε ≥ 0
catastrophe
Futuribles =
Disjunction
1- ε non-
catastrophe
It is because there is a probability ε that the deterrence will not work that it works
with a probability 1- ε.
Unbestimmtheit in Projected Time
ε > 0
Superposition
1-ε
The fact that the deterrence will not work with a strictly positive probability ε is what
allows for the inscription of the catastrophe in the future, and it is this inscription
that makes the deterrence effective, with a margin of error ε.
MAD or the Powerlessness
of Nuclear Deterrence
Alter Ego
•
1
A
r
(0,+1)
r: renounces
A: attacks
Ego
•
2
R
(- N, -N)
Y
(+1, 0)
R: retaliates
Y: yields
N: very large number
Left number: Alter Ego's payoff
Right number: Ego's payoff
5. Projected Time
in Nature
Chance and Necessity
Two principles of evolution
A) Order from noise
Buffon's needle
d
d/2
Buffon's needle:
intersection ratio over time
1
4
2
Order from noise
1
0.318309
3
0
t
10,000,000
Buffon's needle:
intersection ratio over time
1
4
2
1/
π
Order from noise
1
3
0
t
10,000,000
B) Complexity from noise
Complex, Self-organized Systems
Complex systems, made up of many elements interacting in
nonlinear ways, possess remarkable properties—so-called
emergent properties—that justify their description in terms
that one should have thought had been forever banished from
science in the wake of the Galilean-Newtonian revolution.
Thus it is said of these systems that they are endowed with
“autonomy,” that they are “self-organizing,” that their paths
“tend” toward “attractors,” that they are “path-dependent,”
that they have “intentionality” and “directionality”—as if their
paths were guided by an end that gives meaning and direction to
them even though it has not yet been reached; as if, to borrow
Aristotelian categories, purely efficient causes were capable of
producing effects that mimic the effects of a final cause.
Double Mediation
2 absent-minded professors
Imitation
Alter
Ego
Imitation
Polya's urn
Polya's urn:
color ratio over time
1
1
1/2
Complexity from noise
4
2
0
3
t
10,000,000
Complexity from noise
EMERGENCE
ATTRACTOR
DYNAMICS
CONVERGENCE
The dynamics converges towards an attractor
that is generated by itself. The evolution is said
to be path-dependent.
Variation on
the two absent-minded professors case
La forme est à la fois formée et
formante.”
La composition de la
Jeune Parque,
ce fut comme
la croissance
naturelle d une
fleur artificielle.
Paul Valéry (1917)
The Economic and Financial Crisis
ANNEX
Quantum Paradoxes
Newcomb to Backward Induction
in From
Human
Decision-Making
A New Concept of
Equilibrium
in Game Theory
Projected Equilibrium
Peter L
•
1
Mary
•
2
T
T
(1, 0)
( 0, 2)
L
Peter L
•
3
T
( 3, 0)
Mary L
•• ••
N-1
T
(0, N-1 )
Peter
•
N
L
(0, N)
T
(N, 0)
Naïve Backward Induction
Paradox
In an extensive form game, let s call Projected Equilibrium a fixed
point of the closed loop that links past and future in Projected Time.
Expectation/Reaction
Past
Future
Causal Production
Projected Time
The future is fixed.
The past is open.
The past and the future must come together in a closed loop: the
future is the fixed point of the loop. If they don’t, the past is
said to preempt the future.
Every possible occurs, either in the present or in the future ==>
That which does not occur is impossible.
Theorem 1: There exists a constructive algorithm that
determines the projected equilibrium(s) for any decision tree
while respecting the two conditions:
•  C1: The actions that are preempted by the past they bring
about cannot be chosen.
•  C2: Between two or several actions that are not preempted
by the past they bring about, an agent chooses the one he
prefers.
TOL with 3 legs
Peter
•
1
T
(1, 0)
L
Mary
•
2
T
(0, 2)
L
Peter
•
3
L'
(0, 3)
T'
(3, 0)
Let us use the symbol -> to designate the past's reaction function. We have: PL' -> ML ->
PT, which invalidates PL' as a possible future. Besides: PT' -> MT -> PT; therefore MT is
not possible, and we make the correction: PT' -> ML -> PL, which constitutes the
projected equilibrium.
TOL with 4 legs
Peter
•
1
T
(1, 0)
L
Mary
•
2
T
( 0, 2)
L
Peter
•
3
L' Mary
•
4
T'
( 3, 0)
L'
(4, 0)
T'
(0, 4)
MT is impossible (for -> PT), and therefore cannot veto PT'. If PT', then ML, which
brings about PL. Therefore PT' is possible, and vetoes MT'. Let us try ML' -> PL' ->
MT -> PT. MT is impossible (we knew that already!), we must then proceed to: ML' > PL' -> ML -> PL, which is fine
Forward Induction Game
Peter
•
1
V
(2, 0)
H
Mary
•
2
V
(3, 1)
H
Peter
•
3
H'
(1, 2)
V'
(0, 0)
The backward induction solution to this game is, absurdly enough, PV. The
irrelevant "tail", MH, PH', PV', suffices to prevent the Pareto improvement PH, MV.
However, let us verify that such is the projected equilibrium.
PH' -> MH -> PV shows that PH' is impossible.
PV' -> MV -> PH: MV is possible, and vetoes PV'.
Therefore, Peter does not play at 3 on the equilibrium path; which
means that MH is impossible.
MV -> PH: therefore PH, MV is the projected equilibrium.
Theorem 2
For any decision tree, there is one and only one
projected equilibrium.
No other outcome
Pareto-dominates it.
Ghislain Fourny & Stéphane Reiche, 2008
Theorem 3
For any decision tree, the projected equilibrium is
the solution to a Newcomb problem in which the
past is the essentially omniscient Newcomb
predictor and the future is the Newcomb agent.
Biped: Assurance Game
Peter
•
1
D
(0, 0)
C
Mary
•
2
D
(- 1, + 2)
Times: 1 and 2;!
C: Cooperation; D: Defection.!
C
(+ 1, + 1)
Peter
•
1
D
(0, 0)
C
Mary
•
2
C
(+ 1, + 1)
D
(- 1, + 2)
Mary is the Newcomb agent, and Peter the Newcomb predictor. Mary's
reasoning is the following:
(1) If I had the hand at 2, and I were to play C, Peter would have
predicted it, and, reacting to the best of his interest, would have
played C at 1. We would get +1 each.
(2) If I had the hand at 2, and I were to play D, Peter would have
predicted it, and, reacting to the best of his interest, would have
played D at 1. Therefore, I wouldn't have the hand at 2. Hence a
contradiction.
The two premises of (2) lead to a contradiction; therefore one entails
the negation of the other. Whence:
(3) If I had the hand at (2), I would play C.
Peter
•
1
D
(0, 0)
C
Mary
•
2
C
(+ 1, + 1)
D
(- 1, + 2)
The disjunction between (1) and (2) illustrates Alvin Plantinga s
solution to Newcomb s Paradox: it expresses Mary's counterfactual
power over the past and the violation of the principle of the
fixity of the past.
However, in the case of an extensive form game, this power seems
to have vanished into thin air, along with the agent s free will, since
she actually cannot choose to play D. What is the nature of this
impossibility? Is there a way to save free will against essential
foreknowledge?
The solution I have proposed is the following. Before Mary takes
action, she does have the choice between C and D. If choosing D is a
possibility, it is because as long as Mary has not taken action, her
past – here, Peter's choice – is as yet indeterminate. When Mary
acts, her choice determines her past. Were she to choose D, she
would be prevented from acting. It seems as if she never could
choose D, but this impossibility is only retrospective.
What is being jettisoned here is
not only the principle of the fixity of the past,
but also the principle of the reality of the past.
Newcomb problems resonate with quantum informational
problems.
Once Mary takes action©, it turns out that she
could never have acted otherwise – although before
taking action, it was true that she could have acted
otherwise. The future is necessary but not before
it occurs. Once it occurs©, the future appears to be
fixed, i.e. counterfactually independent of past
action.
The indeterminacy of the past as long as action
has not been performed along with the fixity of
the future once action is taken serve to define a
metaphysics of temporality which constitutes
"Projected time.
©: Hidden Future Perfect.
Alvin Plantinga s Way Out
and Its Limits
Naïve Newcomb
Choose
–  Either 2 boxes
–  Or opaque box only
Transparent Box: $1,000
Opaque Box: Either
$1,000,000 or $0
Predictor: put $1,000,000 in opaque box iff he
predicted that subject would choose opaque box
only.
Naïve Newcomb
•  Expected Utility --> One box
•  Dominant Strategy --> Two boxes
Theological Newcomb
Alvin Plantinga
•  God s essential foreknowledge and human
free will.
•  Ockham s Way Out.
•  Newcomb defeats Ockham s Way Out.
•  Counterfactual Power over the Past
--> Violation of the Principle of the Fixity of
the Past.
God existed at t1, He believed at t1 that S would do X at
t2 > t1,
and it is in the power of S at t2 to refrain from doing X at
t2
Incompatibilist argument
St2
St2
St2
God believed at t1 that S would do X at t2
If God believed at t1 that S would do X at t2,
then S does X at t2
----------------------------------------------------------S does X at t2
St [p] = p is true and S is not free at t to perform an act such
that, if she were to perform it, p would be false.
God existed at t1, He believed at t1 that S would do X at
t2 > t1,
and it is in the power of S at t2 to refrain from doing X at
t2
• 
Ockham's Way Out
• 
[God believed at t1 that S would do X at t2] is a soft fact about t1.
• 
Alvin Plantinga' s Way Out: Counterfactual power over the past
•  It is in the power of S at t2 to do something such that,
if she were to do it, God would not have had at t1 the belief that He actually
had.
•  Newcomb à It is in the power of S at t2 to do something such that,
if she were to do it, a hard fact about the past – e. g. the presence
or absence of a million dollars in a box – would have been different
from what it was.
Fri, 21 Jun 1996
Dear Prof. Dupuy,
Thanks you for your note and the copy of your paper. […]
Thus I somewhat prefer [my solution] to your more drastic solution of denying that
there really has been a past. You say that before you act, it is only a
soft fact that there is a million dollars in box A; but the fact is on your
view, before you act, it isn't a fact at all, hard or soft. It becomes a
fact when you act, just as the wave function collapses at a certain time
and it becomes at that time a fact that the cat is dead. Before that, it
isn't a soft fact that the cat is dead (alive), it isn't a fact at all. It
isn't alive, and it isn't dead. What can be said about it isn't all that
clear, but clearly it isn't either alive or dead. In fact it isn't either
alive or not alive, although it does exist. This is also very hard to
believe, and if quantum mechanics really does entail that it is possible
for a thing to exist, but to be neither alive nor not alive, red or not
red, etc, I guess I would take that as a good reason to treat quantum
mechanics instrumentally rather than realistically.
So I don't think we need go to quite those lengths to solve the
Newcomb puzzle.
I hope you are flourishing.
--Alvin Plantinga
---------------------------------Alvin Plantinga
Dept. of Philosophy
Univ. of Notre Dame
----------------------------------