|
|
|
|
|
PDF and .doc files of the overheads used for this presentation are available from the Physics and Faith home page or from the download page
Topics 1.1. Review of the Contingency of the Laws of Physics 1.2. Review of the "Boundary" of the Universe at Time = 0 1.3. A Question About the Second Contingency, and Two New Contingencies
2. Can Physics Explain the Initial Singularity? 2.1. The Limitations of General Relativity 2.3. Metaphysics in the Guise of Physics 2.4. Some Possible Physical Explanations for the Initial Singularity 2.4.1. Introduction 2.4.2. Hartle-Hawking Quantum Cosmology
3. The Contingency of All of Space-Time
4.1. Introduction 4.2. Trivial Anthropic Principle 4.3. Weak and Strong Anthropic Principles 4.3.1. Introduction 4.3.2. Examples of the Striking Coincidences in the Universe That Has Allowed Life To Exist 4.3.2.1. Carbon Atom Energy Levels 4.3.2.2. Dirac's Large Number Hypothesis 4.3.3. What is the Explanation For These Striking Coincidences? 4.3.3.1. The Explanation Offered by the Weak Anthropic Principle 4.3.3.2. The Explanation Offered by the Strong Anthropic Principle
1. Introduction Last session we considered two contingencies or dependencies in physics, that are unexplained by physics itself, that might be considered "rumors" of God:
1.1. Review of the Contingency of the Laws of Physics Two questions in particular arise as we consider the mathematical nature, beauty and elegance of the first contingency, the laws of physics
In considering the mystery of the source of the Universe's rationality:
“the universe, in its rationale beauty and transparency, looks like a world shot through with signs of mind, and maybe, it's the "capital M" Mind of God we are seeing” - John Polkinghorne
In considering the mystery of the comprehensibility of the universe's rationality:
“. . . there is some deep-seated relationship between the reason within (the rationality of our minds - in this case mathematics) and the reason without (the rational order and structure of the physical world around us). The two fit together like a glove.” - John Polkinghorne
A Christian may speculate that this deep-seated relationship between the reason within and the reason without may be a reflection that human beings were made in the image and likeness of the source of that rationality, God.
1.2. Review of the "Boundary" of the Universe at Time = 0 The second contingency we explored last session was the "boundary" of the universe at time = 0 (the "Big Bang") of classical cosmology.
The Penrose-Hawking Singularity Theorem:
Non-quantum physics (General Theory of Relativity) cannot explain what "caused" the universe to "appear" immediately after time = 0: Can this contingency of the “boundary” at time = 0, the initial space-time singularity, be a sign of God's creatio ex nihilio?
1.3. A Question About the Second Contingency, and Two New Contingencies In this session we raise the question whether physics can explain the second contingency -- the initial singularity, the boundary of the universe at time = 0. If so, the rumor of God we found there might be a "false" rumor, a "God of the Gaps."
Then we look at two additional contingencies or dependencies in physics that are unexplained by physics itself, that might be considered "rumors" of God:
2. Can Physics Explain the Initial Singularity? 2.1. The Limitations of General Relativity The Penrose-Hawking Singularity Theorem
But we know Einstein's General Theory of Relativity -- the best theory of gravity we have -- does not include quantum effects, and hence is an incomplete theory.
2.2. The "God of the Gaps" Finding "rumors" of God based on something unexplained by an incomplete theory of physics, "rumors" based on a "gap" in our scientific knowledge, is risky. Later scientific discoveries and theories may fill in those "gaps" with purely physical explanations, and our rumor of God is then revealed as a "false" rumor.
"God of the Gaps": finding rumors of "God" in the "gaps" where our knowledge of physics is incomplete, where later more complete physical theories may fill in those "gaps" with a purely physical explanation.
2.3. Metaphysics in the Guise of Physics The opposite danger to a "God of the Gaps" is proposing a "physical theory" whose significant content:
A "theory" that suffers from (1) and (2) is not physics, it's metaphysics
2.4. Some Possible Physical Explanations for the Initial Singularity 2.4.1. Introduction There is no complete or accepted theory of quantum gravity. Some preliminary work however, suggests the "initial singularity" can be explained:
2.4.2. Hartle-Hawking Quantum Cosmology Hartle-Hawking proposed a "no boundary conjecture" quantum cosmology. In this proposal, the dimension we call time becomes "fuzzy" and turns into a fourth spatial dimension as we approach "time = 0." Thus there is no "beginning" to the universe -- time becomes meaningless as we "approach" "time = 0"
Hawking challenges us to consider the theological significance of a universe where there is no "defined" beginning:
So long as the universe had a beginning, we could suppose it had a creator. But if the universe is really completely self-contained, having no boundary or edge, it would have neither beginning nor end: it would simple be. What place then, for a creator? --Stephen Hawking
2.4.3. Ekpyrotic Universe Attempts to find a comprehensive theory of quantum gravity include the use of "string theory," where the fundamental entities that rise from quantum physics are not points, but 2-dimension "string" like objects In 1990's, a more general class of theories called "M-theories" became popular. The "M" originates from "membranes," for in these theories, the fundamental entities that are the building blocks of matter are objects of 2 or more dimensions
From the M-theories, comes "Braneworld Scenerio" as a description of the universe:
A proposal for the origin of our universe (a cosmogony) that is based on the Braneworld Scenerio is the Ekpyrotic Universe. In this proposal, the
(A recent refinement of the Ekpyrotic Universe was published in Science, May 24, 2002, p1436)
2.5 Status of the "Initial Singularity" of the Big Bang as a Rumor of God If:
is correct, then there may a "physical"* explanation for the initial "singularity" that fills the unexplained "gap" in our physics. There may be no true "rumor" of God here, but just false rumor, a "God of the Gaps."
It may also be true that the ultimate Quantum Theory of Gravity (and the Quantum Cosmology derived from it) cannot eradicate the initial singularity, or that the Ekpyrotic Universe proposal never turns out to be more than a "metaphysics in the guise of physics"
At best, we can say that the "boundary" of the universe at time = 0 (the "Big Bang") of classical cosmology can be considered a "rumor" of God that lives in the tension between concerns of a "God of the Gaps" and "physics in the guise of metaphysics"
3. The Contingency of All of Space-Time We may well ask why we should obsess about whether the "initial singularity" has a physical explanation or not. For why should we give any one "point" in space-time (the initial "singularity") any special significance? Does not every point of space-time demand an explanation?
These questions pose the unexplained contingency of All of Space-Time.
Some quotations:
...creation ex nihilo means sustaining the universe in existence at all times. One should not think of space-time as "coming into existence" anyway. Rather, one says that space-time (or the universe) simply is….Hence, all moments have a similar relation to the Creator. Either they are all "always there," as a brute fact, or they are all equally created - philosopher Willem Drees
God is not a God of the edges, with a vested interest in beginnings. God is the God of all times and all places - John Polkinghorne
God is the creator of the world Now. His act of creation is a continuing act, not just something done fifteen thousand million years ago, but something being done today which will continue to be done tomorrow" - John Polkinghorne
"God is holding a fruitful, rationally beautiful world in being" - John Polkinghorne
...for in him all things in heaven and on earth were created, things visible and invisible, whether thrones or dominions or rulers or powers -- all things have been created through him and for him. He himself is before all things, and in him all things hold together. - St. Paul, Colossians 1:16-17, NRSV
The Christian explanation for the contingency of all of the space-time is that God sustains the universe at all times and in all places
4. The Anthropic Principle 4.1. Introduction Before the scientific revolution in the 16th century, most views of nature assumed the Ptolemaic Principle:
The theories of Copernicus and the observations of Galileo led to the Copernican Principle:
The findings of cosmology in the 20th century has led us to alternatives to the Copernican Principle, the three versions of Anthropic Principle. The three versions of the Anthropic Principle:
The three versions of the Anthropic Principle are the:
(Some discussions include the Trivial Anthropic Principle under the umbrella of the Weak Anthropic Principle)
4.2. Trivial Anthropic Principle The Trivial Anthropic Principle posits that the existence of human beings should just be considered a datum, just like the data gathered from the telescope. Physical theories must be consistent with this datum:
This version of the Anthropic Principle is called "trivial" in the sense that all physical theories must of course be consistent with reality! The underlying assumption in calling the existence of human beings a mere datum is that the existence of human begins is to be accepted as "brute fact" of no further significance.
4.3. Weak and Strong Anthropic Principles 4.3.1. Introduction Both the Weak Anthropic Principle and the Strong Anthropic Principle accept that the existence of human beings is extraordinary. The existence of life in the universe seems to depend on a series of striking "coincidences" in the laws of physics and the initial conditions in the early universe. These striking "coincidence" demand an explanation.
4.3.2. Examples of the Striking Coincidences in the Universe That Has Allowed Life To Exist Two examples of these striking coincidences are:
4.3.2.1. Carbon Atom Energy Levels Elements up to Lithium-7 were produced in the Big Bang. All heavier elements were made later inside stars
However, the synthesis of the heavier elements is difficult -- the only reason they are produced at all is the extraordinary coincidence that carbon has an energy level that is nearly the same as the energies of three alpha particles (helium nuclei) inside a star. This correspondence allows the reaction:
three Helium-4 nuclei colliding to form one carbon-12 nuclei (3 4He ----------> 12C)
to occur with a high enough probability that a reasonable amount of carbon can be made, and from carbon, still heavier elements. (Physicist say the "cross-section" for the process is resonant, which is a consequence of the matching of the energy levels).
4.3.2.2. Dirac's Large Number Hypothesis Paul Dirac (1902-1984), one of the founders of quantum mechanics, noted that very large dimensionless numbers often arise in particle physics and cosmology. For example:
It can be shown from the physics of stars that these large ratios are required for:
That is: the laws of physics and the initial conditions of the universe seemed "tuned" to allowing:
4.3.2.3. Summary of the Striking Coincidences in the Universe That Has Allowed Life To Exist These and other such examples universe appear to be show that the laws of physics and the initial conditions of the universe appear to be incredibly "fine-tuned" for the production of life The slightest deviations in the physical constants or the laws of physics would have resulted in a sterile universe devoid of stars and life
4.3.3. What is the Explanation For These Striking Coincidences? What is the explanation for the striking "coincidences" in the laws of physics and the constants of nature that has allowed the universe to be fruitful of stars and life?
4.3.3.1. The Explanation Offered by the Weak Anthropic Principle The Weak Anthropic Principle asserts:
The Weak Anthropic Principle explanations of the Many Universes Hypothesis and Chaotic Inflation with multiple domains are presently metaphysical not physical explanations, for these other universes or domains are inaccessible to us, and they do not "fall out" as inevitable consequences of any proven theory
4.3.3.2. The Explanation Offered by the Strong Anthropic Principle The Strong Anthropic Principle asserts that the apparent extraordinary "fine-tuning" of the universe for life is present because life is a requirement for the universe. Either:
4.3.3.3. A Perspective on The Explanations Offered by the Weak and Strong Anthropic Principles: The Execution Parable A perspective on the explanations of "many universes" or "many domains" (Weak Anthropic Principle) versus a Designer (Strong Anthropic Principle) is offered by the Execution Parable of philosopher John Leslie.
The Execution Parable:
What is the rationale explanation for your survival?
Leslie suggests there are only two rational explanations:
Cosmological Physics. John A. Peacock, Cambridge University Press, Cambridge, 1999. Section 3.5. The Anthropic Principle. Cosmology. The Origin and Evolution of Cosmic Structure. Second Edition. Peter Coles, Francesco Lucchin, John Wiley and Sons, West Sussex, England, 2002. Sections 3.3. (The Dirac Theory), 6.4 (Quantum Cosmology), 6.5 (String Cosmology), 7.13 (The Anthropic Cosmological Principle) God, Creation, and Contemporary Physics. Mark Worthing. Fortress Press. Minneapolis. 1996. Quantum Cosmology and the Laws of Nature. Scientific Perspectives on Divine Action. Second Edition. Robert John Russell, Nancey Murphy, and C. J. Isham, editors. Vatican Observatory Publications and the Center for Theology and the Natural Sciences, Berkeley, 1996. Distributed by University of Notre Dame Press Science and Theology: An Introduction. John Polkinghorne, SPCK / Fortress Press, London / Minneapolis, 1998
|
|
|
