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THE RABBIT HOLE. “The physical content of the concept of black-hole entropy derives from the following generalized version of the second law: When common entropy goes down a black hole, the common entropy in the black-hole exterior plus the black-hole entropy never decreases.” https://lnkd.in/d_-_tga View in LinkedIn

BLACK HOLE ENTROPY. “A different approach making use of the specific properties of Kerr black holes and of concepts from information theory leads to the same conclusion, and suggests a definite value for the constant.” https://lnkd.in/d_-_tga View in LinkedIn

THE EQUATION. “Considerations of simplicity and consistency, and dimensional arguments indicate that the black-hole entropy is equal to the ratio of the black-hole area to the square of the Planck length times a dimensionless constant of order unity.” https://lnkd.in/d_-_tga View in LinkedIn

THE FOOTNOTE. “Decoherence is an important aspect of quantum theory’s ‘recovery’ of a classical realm.” https://lnkd.in/dMm_YkR View in LinkedIn

OTHER ISSUES. “But there are many interpretative issues about quantum theory, such as entanglement and non-locality, which we need not engage here.” https://lnkd.in/dMm_YkR View in LinkedIn

ONLY DEFINED BY RELATION. “So much the worse, it seems, for the relationist tradition, stemming from Leibniz through Berkeley and Mach, of denying that space, time (and space-time), and their parts, are objects; and of conceiving them instead as a system of spatiotemporal relations between bodies. For the bodies have become diaphanous and omnipresent fields, which are themselves complicated structures of properties and relations among spacetime points.” https://lnkd.in/dMm_YkR View in LinkedIn

SPACETIME AS OBJECTS. “And so it is natural to presume that all these are to be construed as properties of (and relations between) points, or higher-order properties and relations. In short, we arrive at the doctrine now called ‘substantivalism’: that spacetime points are genuine objects, indeed are the basic objects of physical theory.” https://lnkd.in/dMm_YkR View in LinkedIn

THE CHRONOGEOMETRY OF REALITY. “In short, the effect has been for matter to now play second fiddle to space and time. As these field theories, both classical and quantum, are presented to us, their basic objects seem to be just spacetime points. All else—matter, fields, and even the metrical structure of spacetime, the ‘chronogeometry’ of the world—are represented as mathematical structures defined on these points; in particular, as just emphasised, physical quantities for matter and fields are represented by structures defined point by point.” https://lnkd.in/dMm_YkR View in LinkedIn

TRANSMOGRIFICATION. “Furthermore, this assimilation of matter to the concept of a field continued with quantum theory. Even elementary quantum theory has a formulation (wave mechanics) which can be thought of as a field theory. And this picture deepens with the advent of quantum field theory: here physical quantities describing matter are again represented by a field; albeit in a transmogrified form in which an operator (rather than a simple real number) is associated with each space, or space-time, point.” https://lnkd.in/dMm_YkR View in LinkedIn

TIME IN QUANTUM GRAVITY. “On the other hand, the problem of time is about ‘finding’ a time in quantum gravity theories: and so not, in the first instance, about finding some kind of classical limit of, or classical approximation to, such theories.” https://lnkd.in/dMm_YkR View in LinkedIn