by: Seth Lloyd, read in 2014
40 "...entropy is the information required to specify the random motions of atoms and molecules—motions too small for us to see. Entropy is the information contained in a physical system that is invisible to us.
Entropy is a measure of the degree of molecular disorder existing in a system: it determines how much of the system's thermal energy is unavailable for conversion into mechanical work—how much of its energy is useful." How about reconciling these completely different definitions?
42 "The remainder of the information contained in the matter of the photograph is invisible. This invisible information is the entropy of the atoms." Invisible to whom?? Are humans with good eyesight a necessary constituent of the definition of entropy?
42 "The laws of thermodynamics guide the interplay between our two actors, energy and information." Sounds like the cosmogony of Beon Theory.
55 "James Clerk Maxwell, Ludwig Boltzmann, and Josiah Willard Gibbs—discovered that the thermodynamic quantity known as entropy was, as we've noted, a form of information: namely, information that isn't known." Isn't known by whom??
65 "Information is Physical" I'd say information is a pattern of physical or mental entities that has meaning to the creator of the pattern.
66 "Properly understood, the second law of thermodynamics rises from the interplay between "visible information," the information we have access to about the state of matter, and "invisible information," the bits of entropy—no less physical—that are registered by the atoms forming that matter." Think about this in terms of different levels of observers or "knowers" in the sense of Rosenberg"s hierarchy of Natural Individuals. Maybe in some sense more is "known" as you go up the hierarchy and in another sense less is "known" as you go up.
74 "It is the demon's ability to get information about the atoms that allows him to accomplish this apparent violation of physical law."
81 "...different observers can assign different values to the entropy of a system."
81 "For the purpose of the second law of thermodynamics, the important quantity is the total amount of information in a physical system. The total amount of information, known and unknown, in a physical system does not depend on how it is observed." Wait a minute! Which is it? Is entropy the unknown information or the total information? Is entropy the information "invisible to us"? Or is entropy the total = invisible + visible information? To be consistent, you should say "for the purposes of the First Law of Thermodynamics, the important quantity is the total...", But for the 2nd Law, the important quantity is the unknown information.
81 The argument here that ignorance is infectious and spreads, only makes sense if the "knower" is not also an "observer". Yes, without any feedback, the state of a partially known dynamic system will evolve into a completely unknown system. But if the effects of a known-unknown interaction can be observed, then information is learned and known information increases. The real question is Who exactly are the knowers and observers?
82 "But the entropy of the bits taken together remains constant." This is an oxymoron (see above)
82 "The mutual information is equal to the sum of the entropies taken separately, minus the entropy of the two bits taken together."This definition seems to be dependent on the "controlled NOT interaction. I doubt that it would give the same value for other interactions.
82 "Boltzmann defined the quantity he called H as the degree to which we know the position and velocity of any given atom in a gas." Who's "we" white man? And who "gives" the atom? How is it to be identified if it is not known?
98 "Laplace's demon would have to use at least as much space, time, and energy as the universe itself." My "transfer of omniscience" provides a place and time for this demon as well as for the world.
111 "The state |0> + |1> has a definite value of spin along the sideways axis. If you measure which direction it is spinning about that axis, you always find that it is spinning clockwise." This is a little vague. The vertical spin axis is definitive, being a 1D line, so the spin is definitive. But "sideways" is one of many directions or lines in a plane perpendicular to the original axis. Thus the definition of 'left' and 'right' would depend on what side of the experiment the observer was positioned.
126 "http://www-me.mit.edu/people/personal/slloyd.htm" Link to Deutsch debate on many worlds.
155 "Asimov's great 1956 science fiction story, "The Last Question"...Finally, when all of human intelligence, together with everything else, has been subsumed into Multivac's final incarnation, the universal AC, the computer figures it out and says..."LET THERE BE LIGHT!"" My Transfer of Omniscience
157 "It is thus hard to see how the universe could be a classical computer such as a cellular automaton. If it is, then the vast majority of its computational apparatus is inaccessible to observation." Not if you admit real, large, higher dimensions
163 "The anomalous acceleration of the universe's expansion suggests the presence of yet another form of energy, currently dubbed "quintessence."" AKA Dark Energy or Raw Energy
163 "Current observational evidence suggests that the universe is spatially infinite, extending forever in all directions." People don't seem to understand the difference between Very Large and Infinite.
169 "This book advocates a new paradigm, an extension of the powerful mechanistic paradigm: I suggest thinking about the world not simply as a machine, but as a machine that processes information. in this paradigm, there are two primary quantities, energy and information, standing on an equal footing and playing off each other." Sounds like Deepak Chopra.
183 "Pluralitas non est ponenda sin necessitate...Plurality should not be posited without necessity." Occam's Razor
187 Elaine Pagels is Heinz Pagels' widow.
187 "We can't [measure complexity]...Things are complex exactly when they defy quantification."
189 "...four categories [of measures of complexity]: first, measures (like algorithmic information) of how hard it is to describe something; second, measures (like computational complexity) of how hard it is to do something; third, measures of the degree of organization in a system; fourth, non-quantitative ideas associated with complexity (like self-organization or complex adaptive systems)."
189 "The laws of physics describe trade-offs and relationships between measurable quantities, and the laws of complexity do the same. A particularly useful tread-off is that between information and effort." It seems like my Transfer of Omniscience works at all scales
191 "...a measure of complexity that referred to physical systems—energy and entropy...thermodynamic depth...the amount of physical resources needed to produce the given physical system—an atom, say, or an elephant." This addresses the question I have been asking for 50 years: What does it take to produce complex systems? It also relates to Greylorn's cosmogony.
192 "Simple regular systems that are easily assembled, such as salt crystals, are typically thermodynamically shallow. Fully random systems, such as our gas of helium atoms, generated by a straightforward random process such as heating, are also thermodynamically shallow. But intricate, structural systems, such as living systems, required a huge investment of useful bits over billions of years to assemble and are thermodynamically deep." How about defining complexity as the extent to which it can be understood? And define understanding to be the ability to conceptually and hierarchically decompose the system into interconnected and interrelated parts. The depth of understanding would be measured by the extent of generality and specificity of the hierarchies. This definition of course also depends on the intellect doing the understanding. The number pi, for example, has greater complexity than a pure random number because human intellect can cite many mathematical relationships involving, or producing the digits of pi but not for a purely "random" number. (That may not be true for a greater intellect and is certainly not true for a lesser intellect.) The ability to write a succinct program to generate a "complex" figure, e.g. a Serpinsky Triangle, demonstrates a depth of understanding. Otherwise, that figure would be deemed as simple as a crystal.
192 In his definition of Thermodynamic Depth, how exactly is the shortest program to be identified or discovered if not by human intellect?
193 "Murray Gell-Mann,...and I have worked to make the notion of effective complexity mathematically precise.
Effective complexity is a simple and elegant measure of complexity. Every physical system has associated with it a quantity of information—the amount required to describe the physical state of the system to the accuracy allowed by quantum mechanics." But how can you define "description" without involving intellect? Isn't a description a means of transferring information from one intellect to another?
193 "The basic way to measure something's effective complexity is to divide that amount into two parts: information that describes the regular aspects of the thing and information required to describe a system's regularities is its effective complexity." How can we be sure that QM specifies the ultimate limits of regularity? Could there not be some advanced intellect who understands Einstein's hidden variables? I maintain that even this definition of "effective complexity" is dependent on the level of intellect involved.
194 "...complexity is a key issue in engineering." Most true.
194 "Determining the effective complexity of a physical system obviously involves a judgment about what constitutes a regularity and what does not." Yes! My point exactly.
194 "...the important bits are those that have to take on particular values or else the system will not do what it's supposed to do." And who exactly is doing the "supposing"? Hmmm?
195 "Any bit that affects the ability of the system to attain its purpose contributes to the system's effective complexity." Are we waxing a little Aristotelian here?
195 "Of course, the definition of purposeful behavior is to some degree subjective." "Some degree"??
195 "...we'll work within the current standard cosmological model...Such a universe is spatially infinite, even at the very beginning." Giant assumption. IMHO unwarranted. How does that square with "simple"?
196 "Before the beginning there is nothing—no space, no time, no energy, no bits." He needs to account for the origin of space, time, energy, and that first bit.
196 "Observational evidence suggests that in the beginning the universe was simple. As far as we can tell, there may have been only one possible initial state, and that state was everywhere the same." "Everywhere"?? How many "wheres" were there?
196 "Now the universe begins to compute." "Now"?? Don't you mean "then"? What was the impetus?
196 "One Planck time later..." "Later"?? Than what? On what scale (dimension)?
196 "As the universe expands,..." What exactly "expands"? The posited "infinite" spatial extent? The number of bits? (Whence??) The knowledge of the first computations? The results? Would you not need at least two "beginning computations" to comprise a gate? or to cause interference?
196 "the number of bits within the horizon grows and the number of ops accumulates." Does the expansion cause the appearance of new bits? If so, how? Or does the appearance of new bits cause the expansion? If so, whence the new bits? Something is missing.
197 "What are these bits? Bits in the early universe represent local values of energy density." Did the bits pre-figure and define the "energy"? If not, what accounts for the the existence of energy?
201 "At the very beginning of the universe, the cosmological process called inflation produced new space and new free energy at a great rate."
201 "Biologists know...less about how life began than cosmologists know about the beginning of the universe."
213 "...all information that exists is registered by physical systems, and all physical systems register information."
213 "I had made a quantum-mechanical model of how one quantum system gets information about another and showed how such apparent violations of the second law of thermodynamics do not cause any actual violations."
©2014 Paul R. Martin, All rights reserved.