Lee Smolin
Time Reborn
From the Crisis of Physics to the Future of the Universe
Penguin Alan Lane, 2013

Keyterms: time, eternity, lunar - sublunar

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XI Preface: What is time?
XIII There is a paradox inherent in how we think about time. We perceive ourselves as living in time, yet we often imagine that the better aspects of our world and ourselves transcend it. What makes something really true, we believe, is not that it is true now but that it always was and always will be true. What makes a principle of morality absolute is that it holds in every time and every circumstance.
We seem to have an ingrained idea that if something is valuable, it exists outside time. We yearn for “eternal love”. We speak of “truth” and “justice” as timeless. Whatever we most admire and look up to - God, the truths of mathematics, the laws of nature - is endowed with an existence that transcends time. We act inside time but judge our actions by timeless standards.
We seem to have an ingrained idea that if something is valuable, it exists outside time. We yearn for “eternal love”. We speak of “truth” and “justice” as timeless. Whatever we most admire and look up to - God, the truths of mathematics, the laws of nature - is endowed with an existence that transcends time. We act inside time but judge our actions by timeless standards.

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The disappearance of Time
13 The universe, for the ancients, was split into two realms: the earthly realm, which was the arena of birth and death, of change and decay, and the heavenly realm above, which was a place of timeless perfection. For them the sky was already a transcendental realm; it was populated by divine objects that neither grew nor decayed.
The division of the world into an earthly realm and heavenly spheres were codified in Aristotelian physics. Everything in the earthly realm was composed of mixtures of four elements: earth, water, air, fire. Each had a natural motion: the natural motion of earth, for example was to seek the centre of the universe. Change followed from the mixing of these four essences. Aether was the fifth element, the quintessence, which made up the heavenly realm and the objects that moved across it.
14 This division was the origin of the connection of elevation with transcendence. God, the heavens, perfection - these are above us, while we are trapped here below. From this perspective, the discovery that mathematical shapes are traced by motions in the sky makes sense, because both the mathematical and the heavenly are realms that transcend time and change. To know each of them is to transcend the earthly realm.
Mathematics, then, entered science as an expression of a belief in the timeless perfection of the heavens. Useful as mathematics has turned out to be, the postulation of timeless mathematical laws is never completely innocent, for it always carries a trace of the metaphysical fantasy of transcendence from our earthly world to one of perfect forms.
38 Doing physics in a box
We live in a universe that is always changing, full of matter that is always moving. What Descartes, Galileo, Kepler, and Newton learned to do was to isolate little pieces of the world, examine them and record the changes in them. They showed us how to display the records of these motions in simple diagrams whose axes represents the positions and times in a way that is frozen and hence amenable to being studied at our leisure.
Notice that
to apply mathematics to a physical system, we first have to isolate it, and, in our thinking, separate it out from the complexity of motions that is the real universe. We couldn't get very far with the study of motion if we worried about how everything in the universe affects everything else.

88 Time Reborn
103 The Cosmological Challenge
The great theories of 20th century physics - relativity, quantum theory, and the Standard Model - represent the highest achievements of physical science. They have beautiful mathematical expressions that result in precise predictions for experiments, which have been confirmed in many cases to great accuracy. And yet I argue that nothing along the lines of these theories can serve as a fundamental theory.
To support this claim, I can point to a feature that all established theories of physics share and which makes it difficult to extend them to the whole universe: each divides the whole world into parts, one that changes over time and the second assumed to be fixed and unchanging. The first is the system being studied, whose degrees of freedom change with time. The second is the rest of the universe; we can call it the background.
Boe: systemstheory: system/environment - fundamental assumptions.
104 The division of the world into a dynamical and a static part is a fiction, but it is an extremely useful one when it comes to describing small parts of the universe. The second part, assumed to be static, in reality consists of other dynamical entities outside the system being analysed. By ignoring their dynamics and evolution, we create a framework within which we discover simple laws.
The challenge we face when extending science to a theory on the whole universe is that there can be no static part, because everything in the universe changes, and there's nothing outside of it - nothing that can serve as a background against which to measure the motion of the rest. The invention of a way to surmount this barrier might be called the
cosmological challenge.
107
a theory of cosmology.
107 We are ready to reverse the expectations that have guided physics from the time of Newton until very recently. Formerly, we thought of theories like Newtonian mechanics or quantum mechanics as candidates for fundamental theories that - if they succeed - would be perfect mirrors of the natural world, in the sense that everything true about nature would be echoed by a mathematical fact that is true of the theory.
The very structure of the Newtonian paradigm, based on timeless laws acting on a timeless space of configurations, was thought to be essential to this mirroring.
I am proposing that this aspiration was a metaphysical fantasy guaranteed to lead to the aforementioned dilemmas and confusions as soon as we tried applying that paradigm to the whole universe.
121 We conclude that the only way to have a scientific cosmological theory that can make falsifiable predictions is if the laws evolved in time. (The prediction of a theory is falsifiable if it could be contradicted by a doable experiment). Roberto Mangabeira Unger puts this more elegantly: Either time is real or it is not. If time is not real, then laws are timeless - but then the choice of laws is inexplicable, for reasons we have already discussed.
If, on the other hand, time is truly real, then nothing, not even the laws, can last forever. If the laws of nature act forever, we are in the Newtonian paradigm, and you could use them to reduce any property of the world at a later time to a property at an earlier time. So time being real means laws don't last forever. They must evolve.
The notion of timeless laws also violates the relational principle that nothing in the universe acts without being acted on. If you choose to except the laws of nature from this principle, seeing them as something outside the universe, you put them outside the realm of rational explanation. To make laws explicable we must consider them as much a part of the world as the particles they act on. This brings them into the purview of changing colours at it. They become explicable only when they participate in the dance of change and mutual influence that makes the world a whole.
Boe: dance of change –becoming (Hegel);
mutual influence – interaction, communication! -
Tales of Time and Change


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140 Quantum Mechanics and the Liberation of the Atom
The reality of time is the key to addressing the mystery of what selects the laws of physics. It does so by supporting the hypothesis that those laws evolve. Taking time as fundamental may also help resolve another great puzzle of physics - that of making sense of quantum mechanics. Time’s reality allows a new formulation of quantum theory that can also illuminate how laws evolve in time
.

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172 The Emergence of Space



252 SmollinTime252: Epilogue - Thinking in Time
All the progress of human civilisation, from the invention of the first tools to our nascent quantum technologies, is the result of the disciplined application of the imagination.
Imagination is the organ that allows us to thrive on the cusp between danger and opportunity; it is an adaption to the reality of time. We are superb hunters and gatherers and processors of information, but we are far more than that: We have a capacity for imagining situations that are not implied by the data we have. Our imagination lets us anticipate dangers before they are imminent, which means we can plan to meet them.
260 Path dependance and path independence:
A system is path-dependant if it matters how the system evolved from one configuration to another – that is, our present circumstances depend not just on where we are but on how we got here. A system is path-independent if everything depends only on its current configuration and nothing depends on how it got here. In a path-independent system, time and dynamics play little role, because at any time the system is either in its unique state or fluctuating slightly around it. In a path-dependant system, time plays an important role.
Boe: I am a path-dependant system!
264 General relativity moved physics to a relational theory of space and time, in which all properties are defined in terms of relationships. Is this mirrored in a analogous movement in social theory? I believe that it is and that it can be found in the writings of Unger and a number of other social theorists. These explore, in the context of social theory, the implications of a relational philosophy according to which all properties ascribed to agents in a social system arise from their relationships and interactions with one another.
267 It may be that all there is to existence is a relationship. But if so, is there an insight yet to be had about how this can all must be the case? These are questions that are too deep for me. Someone with a different training and temperament might be able to make progress on them, but not I. The one thing I can't do is to dismiss the question of what the world really is by calling it an absurd question. Some advocates of science insist that questions science cannot answer are meaningless, but I find this unconvincing - and unattractively narrow-minded. The pursuit of science has led me to conclude that the future is open and novelty is real. Since I defined science by adherence to an ethic rather than a method, I must accept the possibility of scientific methodologies that no one has yet conceived. This brings us to the really hard problem: the problem of consciousness.


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