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The cathedral in Barcelona, a grand old lady. View in LinkedIn

THE STRETCH. “Our washing up is just like our language. We have dirty water and dirty dishcloths, And yet we manage to get the plates and the glasses clean. In language too, we have to work with unclear concepts and form a logic whose scope is restricted in an unknown way, and yet we use it to bring some clarity into our understanding of nature.” (Neils Bohr, page 4) https://lnkd.in/d_2R77E View in LinkedIn

EIGENSTATES. “Decoherence is a process that rapidly puts macroscopic objects (including tiny ones such as dust particles) that interact with their environment (even very slightly, such as with the microwave background radiation) into mixtures, whose components are, in typical cases, approximate position eigenstates. The process diffuses the interference terms characteristic of the macro-object’s initial superposition into the environment, so that its statistical behaviour is as if it is in a mixture—and a mixture of states that have definite values for familiar quantities like position, or quantities very ‘close’ to those like position.” https://lnkd.in/dMm_YkR View in LinkedIn

NO HOWLERS, YET. “Broadly speaking, our conclusion is twofold. First, we concede that there are large conceptual difficulties in both programmes’ attempts to have classical spacetime ‘emerge’ (as well as ferocious technical difficulties). But second, more positively, we see no knock-down conceptual errors, or philosophical howlers, in these attempts, as they have been developed so far. In that sense, there are good prospects for work for the future.” https://lnkd.in/dMm_YkR View in LinkedIn

THE TOWER OF ASSUMPTIONS. “But similarly, when one can asks for an explanation of a law, the explanation will typically invoke another such law (relating them deductively, or by the one being a limiting case of the other), and one can ask for an explanation of that law—so again a regress beckons, and apparently one must eventually accept a ‘mere happenstance’ of laws also.” https://lnkd.in/dMm_YkR View in LinkedIn

THE LOGICAL STACK. “Second, this thought is indeed questionable! After all, one can explain a particular fact; and one can ask for an explanation of a law. Agreed, the explanation of a particular fact will typically invoke another such fact (usually an earlier one, as in what philosophers call ‘causal explanation’), and one can ask for an explanation of that fact—so that a regress beckons, and one is tempted to think that one must eventually accept a ‘mere happenstance’.” https://lnkd.in/dMm_YkR View in LinkedIn

HAPPENSTANCE. “Laws and explanation are central controversial issues in philosophy of science, which of course we cannot enter here. But we only need two uncontroversial points. First, there is a strong temptation to think of the laws (in our special case: differential equations) as being truly explanatory, while the statements of particular fact (boundary conditions) are not explanatory, because they are matters of ‘mere happenstance’.” https://lnkd.in/dMm_YkR View in LinkedIn

EMERGENCE. “The deceptive picture: Emergence is not a process in time. But this ‘emergence’ is not a process in time: Hartle and Hawking’s proposed ‘framework’, and others such as Vilenkin’s, stands in no temporal relation to classical spacetime, or any of its parts (regions or points), even very early ones.” https://lnkd.in/dMm_YkR View in LinkedIn

More sumptuous Barcelona stucco that is pure organic nature in the spirit of Gaudi. View in LinkedIn

HAWKING RADIATION. “The origin of the ‘Euclidean’ approach to quantum gravity lies in Hawking’s remarkable discovery in 1974 that a black hole will radiate particles with a thermal spectrum via a quantum-mechanical process.” https://lnkd.in/dMm_YkR View in LinkedIn