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The Universal Arrow of Time
Get PDFThe Arrow of Time is an empirical feature of nature – time has a direction from the past to the future. However, the laws of Quantitative Science do not generally include the Arrow of Time. It is shown that this is because the Arrow of Time is a qualitative feature of nature that cannot be captured by Quantitative Science. To capture the Arrow of Time, a Qualitative Paradigm of Science is introduced that is a generalisation of the Mathematical Philosophy of Nature underpinning Quantitative Science. Within this paradigm, the Arrow of Time is captured in a new universal Law of Nature – the Universal Arrow of Time. Since Quantitative Science cannot capture the Arrow of Time, the special sciences cannot in general be reduced to Quantitative Science
Popper on irreversibility and the arrow of time
Get PDFPopper challenges the mainstream account of irreversibility, which refers to thermodynamics, by putting forward three theses: (1) There are irreversible processes of wave-production. (2) These processes are independent of the irreversible processes described by thermodynamics. (3) The irreversible processes described by thermodynamics do not have a cosmic significance. Hence, Popper traces irreversibility back to radiation instead of increase in entropy. However, I shall argue that Popper’s account runs into the same problem as the mainstream account: Both these accounts presuppose initial conditions of the universe that seem to be at least as improbable as anything that is explained by referring in the last resort to these initial conditions. Thus, neither thermodynamics nor radiation provides for an explanation of irreversibility. The appropriate place to look for such an explanation is cosmology. Popper’s main motivation in favouring radiation over entropy increase as the source of irreversibility is that he regards a statistical theory of the arrow of time as being unacceptable. By the arrow of time, he means the flow of time in the sense of a temporal view of the universe. I shall claim that irreversible processes do not provide an argument for assuming an arrow of time in this sense. A Newtonian world can include an arrow of time without having to contain irreversible processes. Special relativity suggests an atemporal view of the universe, the so-called block universe view. The block universe can include irreversible processes such as the ones of radiation and entropy increase. General relativity does not change that matter. Hence, in order to make a case for a physical basis of the arrow of time in the sense of a temporal view of the universe, other arguments would be needed than Popper’s argument building on irreversible processes
Does a computer have an arrow of time?
Get PDFIn [Sch05a], it is argued that Boltzmann's intuition, that the psychological arrow of time is necessarily aligned with the thermodynamic arrow, is correct. Schulman gives an explicit physical mechanism for this connection, based on the brain being representable as a computer, together with certain thermodynamic properties of computational processes. [Haw94] presents similar, if briefer, arguments. The purpose of this paper is to critically examine the support for the link between thermodynamics and an arrow of time for computers. The principal arguments put forward by Schulman and Hawking will be shown to fail. It will be shown that any computational process that can take place in an entropy increasing universe, can equally take place in an entropy decreasing universe. This conclusion does not automatically imply a psychological arrow can run counter to the thermodynamic arrow. Some alternative possible explanations for the alignment of the two arrows will be briefly discussed
Arrow Lakes Historical Society Oral History Interviews
No full textThis collection contains oral history interviews conducted by Arrow Lakes Historical Society volunteers with longtime residents of the Arrow Lakes/upper Lardeau area. The project commenced in 2016. If you are a longtime resident of the region and would like you or your family's history preserved in an oral history interview, please contact the Arrow Lakes Historical Society
The Arrow of Time in Cosmology
Get PDFScientific cosmology is an empirical discipline whose objects of study are the large-scale properties of the universe. In this context, it is usual to call the direction of the expansion of the universe the "cosmological arrow of time". However, there is no reason for privileging the radius of the universe for defining the arrow of time over other geometrical properties of the space-time. Traditional discussions about the arrow of time in general involve the concept of entropy. In the cosmological context, the direction past-to-future is usually related to the direction of the gradient of the entropy function of the universe. But entropy is a thermodynamic magnitude that is typically associated with subsystems of the universe: the entropy of the universe as a whole is a very controversial matter. Moreover, thermodynamics is a phenomenological theory. Geometrical properties of space-time provide a more fundamental and less controversial way of defining an arrow of time for the universe as a whole. We will call the arrow defined only on the basis of the geometrical properties of space-time, independently of any entropic considerations, the "cosmological arrow of time". In this paper we will argue that: (i) it is possible to define a cosmological arrow of time for the universe as a whole, if certain conditions are satisfied, and (ii) the standard models of contemporary cosmology satisfy these conditions
The black arrow : a tale of the two roses /
No full textIn fifteenth-century England, when his father's murderer is revealed to be his guardian, seventeen-year-old Richard Shelton joins the fellowship of the Black Arrow in avenging the death, rescuing the woman he loves, and participating in the struggle between the Yorks and Lancasters in the War of the RosesAuthorized edition (cover)In fifteenth-century England, when his father's murderer is revealed to be his guardian, seventeen-year-old Richard Shelton joins the fellowship of the Black Arrow in avenging the death, rescuing the woman he loves, and participating in the struggle between the Yorks and Lancasters in the War of the RosesMode of access: Internet
Arrow Lakes Historical Society Books & Manuscripts
No full textThis collection contains digital copies of publications from the holdings of the Arrow Lakes Historical Society Archives with the necessary copyright permissions
Low power resettable optical fuse based on the amorphous silicon ARROW fiber
No full textWe present a silicon antiresonance reflecting optical (ARROW) fiber that has power dependent transmission properties. When the throughput power exceeds a nominal value the transmission band structure closes and the fiber can no longer transmit light
ARROW update: 4 November 2005
No full textNo abstract suppliedThis powerpoint document was presented by the ARROW team (2005 : Place unknown). 63 leaves.handle 1959.1/51186pid monash:7605</div
Does Quantum Electrodynamics Have an Arrow of Time?
Get PDFQuantum electrodynamics is a time-symmetric theory that is part of the electroweak interaction, which is invariant under a generalized form of this symmetry, the PCT transformation. The thesis is defended that the arrow of time in electrodynamics is a consequence of the assumption of an initial state of high order, together with the quantum version of the equiprobability postulate
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