“And yet, even though useful quantum computers might still be decades away, many of their payoffs are already arriving. For example, the mere possibility of quantum computers has all but overthrown a conception of the universe that scientists like Stephen Wolfram have championed. That conception holds that, as in the “Matrix” movies, the universe itself is basically a giant computer, twiddling an array of 1’s and 0’s in essentially the same way any desktop PC does.

Quantum computing has challenged that vision by showing that if “the universe is a computer,” then even at a hard-nosed theoretical level, it’s a vastly more powerful kind of computer than any yet constructed by humankind. Indeed, the only ways to evade that conclusion seem even crazier than quantum computing itself: One would have to overturn quantum mechanics, or else find a fast way to simulate quantum mechanics using today’s computers.” http://www.nytimes.com/2011/12/06/science/scott-aaronson-quantum-computing-promises-new-insights.html?_r=1&ref=science&pagewanted=all

“Carson Chow Says:
Comment #2 December 5th, 2011 at 10:35 pm
Nice article but I am confused about this paragraph:

“For example, the mere possibility of quantum computers has all but overthrown a conception of the universe that scientists like Stephen Wolfram have championed. That conception holds that, as in the “Matrix” movies, the universe itself is basically a giant computer, twiddling an array of 1’s and 0’s in essentially the same way any desktop PC does.”

A quantum universe or a classical universe are both computable aren’t they? It’s just that the quantum universe is exponentially “bigger”. In principle, you could have a classical computer just chug away painfully slowly and simulate the quantum universe, no? There is nothing in the “Matrix” universe that says the computation must be efficient is there? There are still just a countable number of possible quantum universes right?”

“Scott Says:
Comment #5 December 5th, 2011 at 10:59 pm
Carson #2: Yes, as the tagline of my blog says, quantum computers can be simulated classically but with exponential slowdown.

What we learn from quantum computing is that, if both quantum mechanics and the prevailing conjectures in complexity theory are valid, then the physical universe can’t be feasibly simulated by a computer that “twiddles an array of 1’s and 0’s in essentially the same way any desktop PC does.”

(That last clause was meant to indicate that I was talking about efficient simulation by conventional computers — i.e., the Extended Church-Turing Thesis, or what Wikipedia calls the Feasibility Thesis. I wish I knew how to put the point more clearly within the constraints of this article, since you’re right that it might be misinterpreted!)

For what it’s worth, Stephen Wolfram, Ed Fredkin, and other believers in “digital physics,” have been very explicit in saying that they think the universe is a classical cellular automaton—basically, a three-dimensional array of pixels—and that their view would preclude exponential speedups from quantum computation. (Wolfram believes that quantum mechanics is wrong, whereas Fredkin believes that quantum mechanics can be efficiently simulated classically.) So, these viewpoints would indeed be ruled out under the assumptions I mentioned above.

A last remark: the Matrix movies aren’t very clear about what type of computer is being used, other than that it’s powered by human bodies! But since they never mention anything about quantum computing, and since the simulation clearly isn’t astronomically slow, it seems reasonable to assume that Keanu Reeves was trapped in some sort of classical simulation. So maybe he could’ve caused the simulation to crash by building a quantum computer and trying to run Shor’s factoring algorithm! For the version where Keanu is trapped in a quantum computation, we might need to wait for the followup trilogy, “The Unitary Matrix” (har, har).”

“Jiav Says:
Comment #8 December 6th, 2011 at 12:59 am
Nice essay Scott, but how could we know our simulation is not astronomically slow?

I’m curious to see if Greg Egan will comment this one ”

http://www.scottaaronson.com/blog/?p=871

Cf. http://theunitedpersons.org/blog/if-the-answer-is-42-what-is-the-question

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INFORMATION AND ITS METRIC “When one speaks of information one refers to that entity shared by all sources that are equivalent up to recoding. This observation suggests a definition of information. Information of the source S is the equivalence class of all recodings of the symbol sequences from S. This is noteworthy since information generally is left undefined in information theory. Information theory only considers the amount of information or rates of production, loss, and transmission, as measured by various entropies. [...]

Recoding R partitions the space I of unique information sources into mutually disjoint subsets. [...]

This suggests the definition of the more abstract information space I [...] as the set of equivalence classes of I under recodings R. [...] Elements of shall be denoted X, Y, and so on. [...] The elements of I shall be the objects of interest in the following. The necessary logical distinction between the class X and its constituent sources will be blurred in the following. A reference to X as an information source should be construed as connoting the common properties of its members. As a source, X is the generic source. We can speak, in a similar vein, of the events or measurements of source X. [...]

Theorem: d is a metric and (I, d) is a metric space. [...]

The theorem indicates that the space of information sources has quite a bit of topological structure. For example, the notion of [epsilon]-balls of “close” information sources, the continuity of functions on information sources, and the limits and convergence of sequences of information sources, can be developed. These and numerical computations of information distances will follow in a sequel. [...]

CONCLUDING REMARKS

One question that arises in this development is why not simply use mutual information instead of the information metric. Aside from the pseudo-geometric picture we have presented, we note that the former measures only a kind of informational correlation. The information metric, however, quantifies the degree of recoding equivalence. And so, it provides some insight into the nature of information itself. Mutual information is a derivative concept that simply reflects the properties Shannon entropy and no more.

The foregoing mathematical development instantiates a particular philosophical view- point, that of phenomenology. All that an observer has to work with in developing an understanding of the world are finite measurements and the attendant information. This intrinsic finiteness derives first and foremost from the limited computation resources available to an observer in a finite space-time region. The information space, as developed here, is the substrate for all perception, quantification, and modeling building. This is then structured with the pseudo-geometry as we have just shown. Only under suitable restrictions is one justified in using observations to form probabilities via (say) frequencies of events.

Information theory was founded on a quantitative measure of the amount of information. The foregoing has given a formal definition of information itself in terms of the equivalence class structure of sources. But what of the “meaning” of this information? A motivation of this work, unstated until this point, was the conviction that an understanding of the topological structure of the metric lattice of inferential logic is necessary for developing a quantitative measure of meaning and of context. Thus, we offer no immediate answer to the question, only the hope that progress can be made. We shall return to this question in the future.”

@inproceedings{crutchfield1990information,
title={Information and Its Metric},
author={Crutchfield, JP},
booktitle={Nonlinear structures in physical systems: pattern formation, chaos, and waves: proceedings of the Second Woodward Conference, San Jose State University, November 17-18, 1989},
pages={119},
year={1990},
organization={Springer}
}

Download: http://scholar.google.com/scholar?cluster=2410770660010935934

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“In the very near future you may be forced to go through a “professional” to get access to your genetic information. [...]” http://www.gnxp.com/wp/2011/03/09/your-genes-your-rights-fdas-jeffrey-shuren-not-a-fan/

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ISCB Public Policy Statement on Open Access to Scientific and Technical Research Literature http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1002014

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Setting standards without kings or votes: “[...] In the intervening 25 years, it turned into a standards organization that creates standards related to the technical operation of the Internet.

However, the IETF [Internet Engineering Task Force] is quite a bit different from traditional standards organizations such as ANSI, ISO, or the IEEE Standards Association. Standards organizations typically have high thresholds for membership—in some cases, you can only join the club if you’re a country—and only make their standards available for a (high) fee. Not so with the IETF: “There is no membership in the IETF. Anyone may register for and attend any meeting. The closest thing there is to being an IETF member is being on the IETF or Working Group mailing lists.”

This comes directly from The Tao of IETF, which is the best introduction into this strange and wonderful world—short of attending a meeting in person. If you don’t have that kind of time, two quotes provide a pretty good feel of how the IETF sees itself: “We reject kings, presidents, and voting. We believe in rough consensus and running code” (David Clark). And: “Be conservative in what you send and liberal in what you accept” (Jon Postel). [...]” http://arstechnica.com/tech-policy/news/2011/01/25-years-of-ietf-setting-standards-without-kings-or-votes.ars

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“P.15: Wiener’s problem: What is the ontological status of information?

Most people agree that there is no information without (data) representa- tion. Following Landauer and Bennett 1985 and Landauer 1987, 1991, and 1996, this principle is often interpreted materialistically, as advocat- ing the impossibility of physically disembodied information, through the equation ‘‘representation5physical implementation.’’ The view that there is no information without physical implementation is an inevitable assumption when working on the physics of computation, since computer science must necessarily take into account the physical properties and limits of the carriers of information. It is also the ontological assumption behind the Physical Symbol System Hypothesis in AI and cognitive science (Newell and Simon 1976). However, the fact that information requires a representation does not seem to entail that the latter ought to be physically implemented. Arguably, environments in which there are only noetic entities, properties, and processes (for example, Berkeley and Spinoza), or in which the material or extended universe has a noetic or nonextended matrix as its ontological foundation (for example, Pythag- oras, Plato, Leibniz, and Hegel), seem perfectly capable of upholding the representationalist principle without also embracing a materialist inter- pretation. The relata giving rise to information could be monads, for example. So the problem here becomes: Is the informational an indepen-
dent ontological category, different from the physical/material and (assuming one could draw this Cartesian distinction) the mental? Wiener, for example, thought that ‘‘information is information, not matter or energy. No materialism which does not admit this can survive at the present day’’ (1948, 132). If the informational is not an independent ontological category, to which category is it reducible? If it is an independent ontological category, how is it related to the physical/ material and the mental? Answers to these questions determine the orientation a theory takes with respect to the following problem:

P.16: The problem of localization: Can information be naturalized?

The problem is connected with P.4 – Namely, the semanticization of data. It seems hard to deny that information is a natural phenomenon, so this is not what one should be asking here. Even elementary forms of life, such as sunflowers, survive only because they are capable of informational processes. The problem here is whether there is information in the world independently of forms of life capable of extracting it and if so, what kind of information is in question (an informational version of the teleological argument for the existence of God argues both that information is a natural phenomenon and that the occurrence of environmental informa- tion requires an intelligent source). If the world is sufficiently information rich, perhaps an agent may interact successfully with it by using ‘‘envi- ronmental information’’ directly, without being forced to go through a representation stage in which the world is first analyzed informationally. ‘‘Environmental information’’ still presupposes (or perhaps is identical with) some physical support, but it does not require any higher-level cognitive representation or computational processing to be immediately usable. This is argued, for example, by researchers in AI working on animats (artificial animals, either computer simulated or robotic). Ani- mats are simple reactive agents, stimulus driven. They are capable of elementary, ‘‘intelligent’’ behavior, despite the fact that their design excludes the possibility of internal representations of the environment and any effective computation (see Mandik 2002 for an overview; the case for nonrepresentational intelligence is famously made in Brooks 1991).

So, are cognitive processes continuous with processes in the environ- ment? Is semantic content (at least partly) external (Putnam)? Does ‘‘natural’’ or ‘‘environmental’’ information pivot on natural signs (Peirce) or on nomic regularities? Consider the typical example provided by the concentric rings visible in the wood of a cut tree trunk, which may be used to estimate the age of the plant. The externalist/extensionalist, who favors a positive answer to P.16 (for example, Dretske or Barwise), is faced by the difficulty of explaining what kind of information and how much of it saturates the world, what kind of access to, or interaction with, ‘‘in- formation in the world’’ an informational agent can enjoy, and how
information dynamics is possible. The internalist/intentionalist (for example, Fodor or Searle), who privileges a negative answer to P.16, needs to explain in what specific sense information depends on intelli- gence and whether this leads to an antirealist view.
The location of information is related to the question of whether there can be information without an informee, or whether information, in at least some crucial sense of the word, is essentially parasitic on the meanings in the mind of the informee, and the most it can achieve, in terms of ontological independence, is systematic interpretability. Before the discovery of the Rosetta stone, was it legitimate to regard Egyptian hieroglyphics as information, even if their semantics was beyond the comprehension of any interpreter? I’ve already mentioned that admitting that computers perform some minimal level of protosemantic activity works in favor of a ‘‘realist’’ position about ‘‘information in the world.’’ Before moving to the next problem, it remains to be clarified whether the previous two ways of locating information might not be restrictive. Could information be neither here (intelligence) nor there (natural world) but on the threshold, as it were, as a special relation or interface between the world and its intelligent inhabitants (constructionism)? Or could it even be elsewhere, in a third world, intellectually accessible by intelligent beings but not ontologically dependent on them (Platonism)?

P.17: The It from Bit hypothesis (Wheeler 1990): Can nature be informationalized?

The neologism informationalized is ugly but useful to point out that this is the converse of the previous problem. Here too, it is important to clarify what the problem is not. We are not asking whether the metaphorical interpretation of the universe as a computer is more useful than mislead- ing. We are not even asking whether an informational description of the universe, as we know it, is possible, at least partly and piecemeal. This is a challenging task, but formal ontologies already provide a promising answer (Smith 2003). We are asking whether the universe in itself could essentially be made of information, with natural processes, including causation, as special cases of information dynamics (for example, information flow and algorithmic, distributed computation, and forms of emergent computation). Depending on how one approaches the concept of information, it might be necessary to refine the problem in terms of digital data or other informational notions.

Answers to P.17 deeply affect our understanding of the distinction between virtual and material reality, of the meaning of artificial life in the ALife sense (Bedau 2003), and of the relation between the philosophy of information and the foundations of physics: If the universe is made of information, is quantum physics a theory of physical information? More- over, does this explain some of its paradoxes? If nature can be informa-
tionalized, does this help to explain how life emerges from matter, and hence how intelligence emerges from life? Of course these questions are closely related to questions listed in section 5: ‘‘Can we build a gradualist bridge from simple amoeba-like automata to highly purposive intentional systems, with identifiable goals, beliefs, etc.?’’ (Dennett 1998, 262).”

OPEN PROBLEMS IN THE PHILOSOPHY OF INFORMATION
LUCIANO FLORIDI
METAPHILOSOPHY Vol. 35, No. 4, July 2004
pp. 554-582

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