scholarly journals Functionalist explanation of spacetime

2019 ◽  
Vol 62 (2) ◽  
pp. 119-131
Author(s):  
Radmila Jovanovic-Kozlowski
Keyword(s):  
Quantum Gravity ◽  
Functional Role ◽  
Physical Theory ◽  
Classical Mechanics ◽  
Fundamental Theory ◽  
Emergent Spacetime ◽  
New Interpretation ◽  
New Research ◽  
Philosophical Debates ◽  
Real Challenge

In contemporary physics, from General relativity and Quantum mechanics to new research programs of Quantum gravity, we can find a vast variety of spacetime structures, which makes the interpretation of this concept a real challenge. Recently, a group of authors advanced a new interpretation of spacetime called ?spacetime functionalism?, with the idea that spacetime should be defined via its functional role in the physical theory, in other words, ?spacetime is what spacetime does?. A material field or an object are spatiotemporal if they play a defined role in a physical theory. The approach is meant to be widely applicable, from classical mechanics to possible new theories of Quantum gravity, where spacetime might not appear at the fundamental theory level. Functionalism can be well combined with the emergent spacetime. It should also shed a new light on traditional philosophical debates between substantivists and relationists and between realists and anti-realists.

scholarly journals Thinking about Spacetime

2021 ◽  
pp. 129-153
Author(s):  
David Yates
Keyword(s):  
Quantum Gravity ◽  
Philosophy Of Mind ◽  
Fundamental Theory ◽  
True Nature ◽  
Fundamental Ontology ◽  
Fundamental Structure ◽  
Space And Time ◽  
Spacetime Structure ◽  
Research Programmes ◽  
Emergent Spacetime

Several different quantum gravity research programmes suggest, for various reasons, that spacetime is not part of the fundamental ontology of physics. This gives rise to the problem of empirical coherence, which I frame in terms of entailment: how could a non-spatiotemporal fundamental theory entail spatiotemporal evidence propositions? Solutions to this puzzle can be classified as realist or antirealist, depending on whether or not they posit a non-fundamental spacetime structure grounded in or caused by the fundamental structure. These approaches place different constraints on our everyday concepts of space and time. Applying lessons from the philosophy of mind, I argue that only realism is both conceptually plausible and suitable for addressing the problem at hand. I suggest a role-functionalist version of realism, which is consistent with both grounding and causation, and according to which our everyday concepts reveal something of the true nature of emergent spacetime.

Physics, Structure, and Reality

2021 ◽  
Author(s):  
Jill North
Keyword(s):  
Scientific Realism ◽  
Physical Theory ◽  
Scientific Explanation ◽  
Classical Mechanics ◽  
Careful Attention ◽  
Coordinate Systems ◽  
Spacetime Structure ◽  
The World ◽  
Background Assumption ◽  
And Mathematics

How do we figure out the nature of the world from a mathematically formulated physical theory? What do we infer about the world when a physical theory can be mathematically formulated in different ways? Physics, Structure, and Reality addresses these questions, questions that get to the heart of the project of interpreting physics—of figuring out what physics is telling us about the world. North argues that there is a certain notion of structure, implicit in physics and mathematics, that we should pay careful attention to, and that doing so sheds light on these questions concerning what physics is telling us about the nature of reality. Along the way, lessons are drawn for related topics such as the use of coordinate systems in physics, the differences among various formulations of classical mechanics, the nature of spacetime structure, the equivalence of physical theories, and the importance of scientific explanation. Although the book does not explicitly defend scientific realism, instead taking this to be a background assumption, the account provides an indirect case for realism toward our best theories of physics.

scholarly journals The Quantum Cosmological Constant

Symmetry ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1130 ◽  
Author(s):  
Stephon Alexander ◽  
Joao Magueijo ◽  
Lee Smolin
Keyword(s):  
General Relativity ◽  
Quantum Theory ◽  
Quantum Gravity ◽  
Cosmological Constant ◽  
Uncertainty Relation ◽  
Time Variable ◽  
Transition Functions ◽  
New Interpretation ◽  
Chern Simons

We present an extension of general relativity in which the cosmological constant becomes dynamical and turns out to be conjugate to the Chern–Simons invariant of the Ashtekar connection on a spatial slicing. The latter has been proposed Soo and Smolin as a time variable for quantum gravity: the Chern–Simons time. In the quantum theory, the inverse cosmological constant and Chern–Simons time will then become conjugate operators. The “Kodama state” gets a new interpretation as a family of transition functions. These results imply an uncertainty relation between Λ and Chern–Simons time; the consequences of which will be discussed elsewhere.

Causation in Classical Mechanics

2010 ◽  
Author(s):  
Marc Lange
Keyword(s):  
Physical Theory ◽  
Classical Mechanics ◽  
The Body ◽  
Causal Relations ◽  
Scientific Explanations

Russell might be interpreted as arguing that physics reveals there to be no causal relations since physics has no need to posit them (just as Laplace said to Napoleon that physics has no need to posit God). Of course, whether physics needs to posit causal relations depends upon what physics needs to do. Russell appears to presume that a physical theory needs merely to predict certain quantities from others. For that purpose, the bare equations suffice. However, it is doubtful that the bare equations are enough to fund scientific explanations. The force on a body and the body's mass apparently explain why the body undergoes a given acceleration, whereas the force and acceleration do not explain why the body possesses a certain mass.

scholarly journals Conceptual Problems in Bell's Inequality and Quantum Entanglement

2020 ◽  
Author(s):  
Ying-Qiu Gu
Keyword(s):  
Quantum Theory ◽  
Quantum Entanglement ◽  
Classical Mechanics ◽  
Bell State ◽  
Bell’S Inequality ◽  
Heisenberg Uncertainty Principle ◽  
Bell's Inequality ◽  
Micro Particles ◽  
Wave Particle Duality ◽  
New Interpretation

The description of the microscopic world in quantum mechanics is very different from that in classical physics, and there are some points of view that are contrary to intuition and logic. The first is the loss of reality, the behavior of micro particles shows randomness and hopping. The second is the loss of certainty, the conjugate physical variables of a system cannot be determined synchronously, they satisfy the Heisenberg uncertainty principle. The third is the non-local correlation. The measurement of one particle in the quantum entanglement pair will change the state of the other entangled particle simultaneously. In this paper, some concepts related to quantum entanglement, such as EPR correlation, quantum entanglement correlation function, Bell's inequality and so on, are analyzed in detail. Analysis shows that the mystery and confusion in quantum theory may be caused by the logical problems in its basic framework. Bell's inequality is only a mathematical theorem, but its physical meaning is actually unclear. The Bell state of quantum entangled pair may not satisfy the dynamic equation of quantum theory, so it cannot describe the true state of microscopic particles. In this paper, the correct correlation functions of spin entanglement pair and photonic entanglement pair are strictly derived according to normal logic. Quantum theory is a more fundamental theory than classical mechanics, and they are not parallel relation in logic. However, there are still some unreasonable contents in the framework of quantum theory, which need to be improved. In order to disclose the real relationship between quantum theory and classical mechanics, we propose some experiments which show the wave-particle duality simultaneously and provide intuitionistic teaching materials for the new interpretation of quantum theory.

The Consumer Revolution, 1650–1800

2022 ◽  
Author(s):  
Michael Kwass
Keyword(s):  
World Trade ◽  
Global Perspective ◽  
Daily Lives ◽  
Public Issues ◽  
Consumer Activism ◽  
Ethical Consumerism ◽  
Consumer Revolution ◽  
Plantation Slavery ◽  
New Interpretation ◽  
Philosophical Debates

The production, acquisition, and use of consumer goods defines our daily lives, and yet consumerism is seen as increasingly controversial. Movements for sustainable and ethical consumerism are gaining momentum alongside an awareness of how our choices in the marketplace can affect public issues. How did we get here? This volume advances a bold new interpretation of the 'consumer revolution' of the eighteenth century, when European elites, middling classes, and even certain labourers purchased unprecedented quantities of clothing, household goods, and colonial products. Michael Kwass adopts a global perspective that incorporates the expansion of European empires, the development of world trade, and the rise of plantation slavery in the Americas. Kwass analyses the emergence of Enlightenment material cultures, contentious philosophical debates on the morality of consumption, and new forms of consumer activism to offer a fresh interpretation of the politics of consumption in the age of abolitionism and the Atlantic Revolutions.

Finding Space in a Non-Spatial World

2021 ◽  
pp. 154-181
Author(s):  
David J. Chalmers
Keyword(s):  
Philosophy Of Mind ◽  
Perceptual Experience ◽  
Functional Role ◽  
Recent Literature ◽  
Cartesian Skepticism ◽  
Scientific Image ◽  
Emergent Spacetime ◽  
Manifest Image

What is the relation between space in the manifest image of perceptual experience and in the scientific image of physics? I will argue that we have moved from spatial primitivism (on which space is understood as a primitive conception that we are acquainted with) to spatial functionalism (on which space is picked out by its functional role). I investigate different forms of spatial functionalism on which the relevant roles are experiential (involving effects on our experience) and non-experiential (involving patterns of causal interactions). I draw connections to functionalism in the philosophy of mind, to Cartesian skepticism, and to recent literature on spacetime functionalism and emergent spacetime.

scholarly journals BORN'S PROPHECY LEAVES NO SPACE FOR QUANTUM GRAVITY

2012 ◽  
Vol 09 (06) ◽  
pp. 1261001 ◽  
Author(s):  
GIOVANNI AMELINO-CAMELIA
Keyword(s):  
Quantum Gravity ◽  
Momentum Space ◽  
Physical Content ◽  
Emergent Gravity ◽  
Max Born ◽  
Emergent Spacetime

I stress that spacetime is a redundant abstraction, since describing the physical content of all so-called "spacetime measurements" only requires timing (by a physical/material clock) of particle detections (at a physical/material detector). It is interesting then to establish which aspects of our current theories afford us the convenient abstraction of a spacetime. I emphasize the role played by the assumed triviality of the geometry of momentum space, which makes room for an observer-independent notion of locality. This is relevant for some recent studies of the quantum-gravity problem that stumbled upon hints of a nontrivial geometry of momentum space, something which had been strikingly envisaged for quantum gravity already in 1938 by Max Born. If indeed momentum space has nontrivial geometry then the abstraction of a spacetime becomes more evidently redundant and less convenient: one may still abstract a spacetime but only allowing for the possibility of a relativity of spacetime locality. I also provide some examples of how all this could affect our attitude toward the quantum-gravity problem, including some for the program of emergent gravity and emergent spacetime. And in order to give an illustrative example of possible logical path for the "disappearance of spacetime" I rely on formulas inspired by the κ-Poincaré framework.

scholarly journals EMERGENCE OF TIME FROM DIMENSIONAL REDUCTION IN NONCOMMUTATIVE GEOMETRY

2006 ◽  
Vol 21 (08) ◽  
pp. 639-647 ◽  
Author(s):  
CHONG-SUN CHU ◽  
OLAF LECHTENFELD
Keyword(s):  
Field Theory ◽  
Quantum Gravity ◽  
Noncommutative Geometry ◽  
Dimensional Reduction ◽  
Euclidean Geometry ◽  
Noncommutative Field Theory ◽  
Fundamental Theory ◽  
Temporal Dimension ◽  
New Form

By considering a new form of dimensional reduction for noncommutative field theory, we show that the signature of spacetime may be changed. In particular, it is demonstrated that a temporal dimension can emerge from a purely Euclidean geometry. We suggest that this mechanism may hint at the origin of time in the fundamental theory of quantum gravity.

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