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Preface
Philosophy of Nature and Quantum Reality
Ian J. Thompson
Department of Physics
University of Surrey
Preface
Contents
1
. Prospects for a Philosophy of Nature
Accommodating Quantum Physics
The Philosophy of Nature
2
. Dispositions
2
.
1
Everyday Dispositions
Propensities: Probabilistic Dispositions
Questions of Meaning
2
.
2
Derivative Dispositions
2
.
3
Are Dispositions Real?
2
.
4
Scientific Explanation of Dispositions
2
.
5
Are Bases ultimately Dispositional, or Non-dispositional?
2
.
6
Objections to Dispositional Bases
(1) Apparent success of structural explanations
(2) The basis of any observed property must be an actual occurrent feature
(3) No logical connections between separate existences (Hume)
(4) Dispositions are essentially relational (Locke)
Summary
3
. Problems in Classical Physics
Can Physics do Without Causal Powers?
3
.
1
Newtonian Physics
3
.
2
Descartes and Leibniz
3
.
3
Aristotle's Physics
3
.
4
Dispositions in Mathematical Physics
4
. The Peculiarities of Quantum Physics
4
.
1
Classical and Quantum Dispositions
4
.
2
Quantum Experiments
4
.
3
Quantum Ontologies
1. Ontology of Events
2. Ontology of Particles
3. Ontology of Waves
4. Ontology of Wave-particle Complementarity
5. Ontology of Propensities
4
.
4
The Problem of Measurements
Measurement by Observations
Measurement by Consciousnesses
Measurement by Actualising
No Special `Measurements'
What to do?
5
. Reconsidering Philosophical Foundations
A Realist Philosophy of Nature
6
. Actuality
6
.
1
On What Can Be Actual
Purely Actual Particulars
Changeless Actualities
6
.
2
Finite or Infinite?
Infinity in Mathematics
Finitism
Redefining the Finite
Potential Infinities
The Mathematics of Possibility
Semantics of Set Theory
Continuity
6
.
3
Choices for Pure Actuality
Actualities are not substances or everyday objects
Newtonian corpuscles cannot be actual
Nothing fixed in spacetime
Actualities are not the instantaneous-present states of objects
Not extended processes
Not indivisible events
A `strand of history' is not actual
Actuality is not space or spacetime itself
Actuality could be a stage in an object
Actualities could be past events
Meaning of term `past-event'
7
. Potentiality
7
.
1
Change as Actualising
Kinesis
Parmenides' arguments
Do potential trees really exist?
Can potentialities themselves be objects?
Is Change (Kinesis) Now Intelligible?
7
.
2
The Analysis of Actualising (Kinesis)
7
.
3
Kinds of Potentialities
8
. A Theory of Space and Time
8
.
1
Possibilities as Places in Space and Time
Point Places in Which Space?
On Real Possibilities
8
.
2
Extensiveness, Space and Time
Extensiveness and the Extensive Continuum
Metrics
Momentum Space?
8
.
3
Past and Future
McTaggart's Argument
Time as the B-series
Time as Becoming
8
.
4
Process Time
No Universal Serial Time
Local Process Times?
8
.
5
One Global Process Time?
1. Some Observer's Legal Time?
2. Centre-of-mass of the universe?
3. General Spacelike Hypersurfaces?
4. Contingent Actualising?
Spontaneous Symmetry Breaking
8
.
6
Necessary and Contingent Ordering
Appearance of a `Current Space'
Appearance of a `Global Process Time'
What Difference the Order Makes
Conclusion: Actualisation and Special Relativity
9
. A Theory of Substance
9
.
1
Traditional Views of Substances
9
.
2
Propensity Fields
9
.
3
Continuants (Substances) Which Endure Through Change?
9
.
3
.
1
Unchanging Continuants
9
.
3
.
2
Changeable Continuants
9
.
4
Questions about Substances
9
.
4
.
1
Individuals
9
.
4
.
2
Matter and Form: Subject and Predicate
Knowability of Matter/Propensity and Form
Prime Matter?
9
.
4
.
3
On Real Essences
9
.
4
.
4
Elements
9
.
4
.
5
On Time and Change
10
. Quantum Substances
10
.
1
Classical and Quantum Theories
10
.
2
Probabilities and Propensities
Heisenberg
Propensitons
10
.
3
Waves, Particles and Complementarity
Wave Behaviour?
Particle Behaviour?
Complementarity?
Two-Slit Experiment
Superpositions and Mixtures
Summary
10
.
4
Measuring as Actualising
Irreversible Processes
10
.
5
Nonlocalities
11
. Two Stages of Propensities
11
.
1
Point Events
Can all interactions be actual events?
Point localisations of the
function?
11
.
2
Actual and Virtual Events as Distinct
Two Stages of Propensities and Events
Actual Events as Selections
Virtual Events
11
.
3
`Gauge' Invariances
1. Equivalent Configuration Spaces
2. Equivalent Phases and Potential Gauges
3. Equivalent `Infinitesimal' Sizes of Virtual Events
4. Equivalent Exchanges of Identical Particles
Summary
11
.
4
Quantum Substances
12
. Measurements and Other Actualisations
12
.
1
The Problem of Measurement
12
.
2
Objective Actualisation - some proposals
12
.
2
.
1
Simple schemes
1. Actuality from present or future connections to our senses
2. Actuality from Composite Objects
3. Actuality from Macroscopic Objects
4. Actuality from Alternative Interactions
5. Actuality from Irreversible Interactions
6. Actuality from Superpositions not inter-transformable
7. Actuality from no general characteristic
8. Actuality from point localisations in space and time
12
.
2
.
2
Schematic Proposals
1. Actualisations outside a `correlation length'
2. Actualisations from some `effective temperature'
3. Actualisations as localisation to gaussians wave-packets
4. Actualisations from logarithmic terms in Schrödinger's equation
5. Actualisations from statistical fluctuations in the Hamiltonian
12
.
2
.
3
Quantitative Proposals
1. Actualisations from energy differences
2. Actualisations from inelastic energy differences
3. Actualisations from gravitational differences
Comments
12
.
3
Mind-dependent Actualisation - some proposals
12
.
4
Conclusions
13
. Summary of the Argument
13
.
1
General Process Logic
13
.
2
When actualities at points in ordinary space and time
13
.
3
When actualities are selections of alternatives
References
Index
About this document ...
Prof Ian Thompson
2003-02-25