The strange properties of the photon: a case study with philosophical implications by Alfred Driessen, Prof. Emer. University of Twente. Talk presented at Journée « Science, raison et foi » on Causalite, Temps et Origine de l'Univers CASTELVIEIL , MARSEILLE, November 12 , 2013 Abstract: When dealing with extremely small and rapidly moving particles, the two great theories of modern physics, Quantum Mechanics and Relativity have to be taken into account. This is especially true for the photon with mass zero and travelling at the speed of light, the maximum speed allowed in Relativity. Strange result are expected, see for example the delayed choice Gedanken-experiment of Wheeler about light travelling over astronomical distances. There is evidence that causality in this and other situations has its origin outside the realm of time. For the philosopher it is a challenging task to understand the observations of the physicist and apply the metaphysical concepts time, space, causality, choice and others adequately. In this talk an attempt is made to look at the challenging behavior of the photon as a physicist as well as a philosopher.

1. Driessen.Alfred@gmail.com
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2. Content
Introduction
photons and the light cone
the strange photon
philosophical considerations
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3. The cave of Plato (Politeia, 380 B.C.)
What we see are the shadows of the world of the ideas
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4. The cave of Plato (Politeia, 380 B.C.)
http://www.youtube.com/watch?v=69F7GhASOdM
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5. characteristics of classical philosophy
classical philosophy
deals with nature
(Greek: physis) of beings
being is central
philosophy of being
real beings
can belong to the visible, observable world;
but also invisible, unobservable beings can be real
the invisible and immaterial is cause of the visible
see, Plato, Aristotle, Thomas Aquino
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6. The demon of Laplace (1794-1827)
We may regard the present state of the universe
as the effect of its past and the cause of its
future. An intellect which at a certain moment
would know all forces that set nature in motion,
and all positions of all items of which nature is
composed, if this intellect were also vast enough
to submit these data to analysis, it would
embrace in a single formula the movements of
the greatest bodies of the universe and those of
the tiniest atom; for such an intellect nothing
would be uncertain and the future just like the
past would be present before its eyes.
A Philosophical Essay on Probabilities, 1814
As a member of the new Academy of Sciences, he presented the
“scientific system” of that academy to Napoleon Bonaparte.
Napoleon asked: “Where is the place for God in your system?”
His answer was: “Majesty, we did not need that hypothesis.”
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7. Statement of De Broglie
Louis De Broglie, 1892- 1987, Nobel prize in 1929
As science progresses, it is constrained to
introduce into its theories concepts of a
metaphysical nature – like those of time,
space, objectivity, causality, individuality.
....Science frequently ends up engaging in
metaphysics without realizing it, and this
is not exactly the safest way of doing
metaphysics.
De Broglie, Revue de metaphysique et de
morale, 1947, 3, p 278.
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8. The cave of Plato and the outside world
inside cave
outside cave
Plato
visible world, caused by
invisible world,
shadow of reality
invisible reality
invisible causes
Aristoteles
part of reality, caused by
visible and invisible causes
invisible reality,
unmoved mover,
invisible causes
De Broglie
science and metaphysics
metaphysics
Laplace
deterministic reality
unnecessary
hypothesis
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9. Content
Introduction
photons and the light cone
the strange photon
philosophical considerations
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10. Space-time diagram
present:
space-like separated
from origin
future/past:
time-like separated from
origin
event at origin:
-- is caused by events in
the past light cone
-- has causal effects on
events in the future light
cone
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11. special and general relativity
light cone in special
relativity
light cone in
general relativity
(curved space)
figures from Penrose
Cycles of Time,
Random House,
London 2010
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12. Space-time diagram (1)
present:
space-like separated from origin
future/past:
time-like separated from
origin
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13. Space-time diagram (2)
train at rest:
at three different moments
long train:
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14. Space-time diagram (3)
moving train:
at three different moments
long train:
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15. Space-time diagram (4)
moving train:
at three different moments
new coordinates of the
moving train
long train:
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16. Space-time diagram (5)
consider two events
<= time line of train
1: at origin
2: outside the light cone
There is an inertial system
where these are simultaneous
example
a traveler in an extremely long
moving train needs only to ask
his colleague at the wagon
at event 2.
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17. Space-time diagram (6)
consider two events
<= time-line of the train
1: at origin
2: inside the light cone
There is an inertial system
where these are at the same
place
example
a traveler in an extremely long
moving train needs only to
look out the window and
wait to see the event.
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18. Space-time diagram (7)
consider two events
1: at origin
2: on the light cone
<= time line of train with speed c
There is an inertial system
where these are simultaneously
at the same place
example
as before, event at the same
place, in addition: because
of time contraction:
interval of time is zero
 t  1  2 / c2  t  1 1  t  0
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19. Space-time diagram (8)
consequence for a
photon:
<= time-line of photon
In the coordinate system of
the photon, the event of
emission and absorption is:
-- instantaneously
-- without distance
emission
absorption
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20. Content
Introduction
photons and the light cone
the strange photon
philosophical considerations
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The Strange Photon
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21. formation of a black hole
light cones in the
vicinity of a black
hole
figure from Penrose
Cycles of Time,
Random House,
London 2010
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22. time dilatation nearby a black hole
x
c  constant 
t
t
x
t
x
speed of light c is
constant in all
coordinate systems,
==> if x becomes
smaller, also t
diminishes
accordingly:
(gravitational) time
dilatation
figure based on
Penrose 2010
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23. A clock visible at light-years distance
nano-clock: excited atom or molecule
emits radiation at a certain frequency
cosmological red shift:
due to time dilatation of rapidly
moving objects:
extreme case: background radiation
gravitational red shift
due to time dilatation nearby a heavy
mass (curvature of space, rotation of
light-cone)
extreme case: horizon of black hole
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24. Penrose about photons
lecture in University of Leiden 2011
The point is that, according to a massless particle, the
passage of time is as nothing. (2010)
Eternity is no time at all, for a photon .(2011)
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25. A Gedanken-experiment by Wheeler 1978
Wheeler's proposal,
experimentally confirmed
(Jacques et al. 2007)
measuring individual photons from a quasar whose image has been
split in two by a galaxy acting as a gravitational lens.
Final state:
1) interference set-up: photon follows both paths;
2) telescope view: photon takes a unique path.
delayed choice made after billions of years
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26. Gravitational lens at 9.5 light-year
gravitational lens: ~1011 mass of sun at 9.5 light-year
source galaxy: ~108 mass of sun at 11.5 light-year,
magnified 40x,
appears as ring with 4 pronounced images
Van der Wel et al. 2013 (arXiv: 1309.2826v1)
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27. Adriaan Fokker, 1887-1972)
A. D. Fokker, Universiteit Leiden (1965)
Perhaps the deepest enigma brought to light by
chronogeometry is the occurrence of zero
intervals, connecting events which are located
by observers with spatial distance and temporal
duration between them. Zero interval means no
separation at all, an immediate transmission of
momentum and energy, as if there were
contiguity……
The mathematical formula is quite simple and
plain, nevertheless it relates to one of God's
secrets and implies His sempiternal ubiquitous
presence.
A.D. Fokker, Time and Space Weight and Inertia,
Pergamon Press, Oxford, 1965
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The Strange Photon
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28. Content
Introduction
photons and the light cone
the strange photon
philosophical considerations
CSR: Culture, Science and Religion
The Strange Photon
pagina 28
12-11-2013

29. The cave of Plato and the outside world
inside cave
outside cave
Plato
visible world, caused by
invisible world,
shadow of reality
invisible reality
invisible causes
Aristoteles
part of reality, caused by
visible and invisible causes
invisible reality,
unmoved mover,
invisible causes
De Broglie
science and metaphysics
metaphysics
Laplace
deterministic reality
unnecessary
hypothesis
CSR: Culture, Science and Religion
The Strange Photon
pagina 29
12-11-2013

30. The cave of Plato and the outside world
inside cave
outside cave
Plato
visible world, caused by
invisible world,
shadow of reality
invisible reality
invisible causes
Aristoteles
part of reality, caused by visible invisible reality, unmoved
and invisible causes
mover, invisible causes
De Broglie
science and metaphysics
metaphysics
Laplace
deterministic reality
unnecessary hypothesis
relativity
photon, object of science
photon is outside time
Penrose
photon, object of science
eternity is no time at all
for a photon
Wheeler
causality in science
delayed choice, causality
of final state
Fokker
relativity and photon
evidence for ubiquitous
presence outside time
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31. Causality
classical philosophy (Aristotle, Aquinas)
whatever is moved is moved by another or whatever is
changed is changed by another.
principle of causality
David Hume
cause: an object followed by another, and where all the
objects similar to the first are followed by objects
similar to the second.
Concerning Human Understanding.
Stephan Hawking:
Within the universe, you always explained one event
as being caused by some earlier event.
A brief history of time.
What about
delayed choice and causality from outside time?
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32. A request to philosophers
A dream:
To bring all knowledge about reality together in a single,
consistent view. For this is needed a consistent philosophy
(metaphysics) without internal contradiction and in
accordance with experience.
Problem:
The current experience accumulated in science is only
accessible to the specialist.
Who will enter the dialogue?
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33. This talk has been presented at the
Journée « Science, raison et foi »
Causalite, Temps et Origine de l'Univers
CASTELVIEIL , MARSEILLE, November 12 , 2013
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