Slashdot Mirror
Calculating A Theoretical Boundary To Computation
TMB writes "Lawrence Krauss and Glenn Starkman, astrophysicists at Case Western Reserve University (and in LK's case, author of a number of books including Physics of Star Trek), just submitted this nice little paper to Phys. Rev. Letters. It claims that in an accelerating universe, the existence of a future event horizon puts a fundamental physical limit on the total amount of calculation that can be done, even in an infinite time. This limit is much smaller than the traditional Hawking-Beckenstein entropy. Among other things, this implies that and Moore's Law must have a finite lifetime, here calculated to be 600 years, and that consciousness must be finite."
Please use the mirrors. In Australia, the closest one is here.
Ummm...read that again. Moore's Law is not the basis of this paper. Physicists and mathematicians using economic theories (yes, Moore's Law is economic in nature) to predict physical laws are neither published nor credentialed. The finiteness of Moore's Law is an implication of the findings of this paper.
Have you read the article? All it states is that no civilisation could possibly extend Moore's Law beyond 600 years. That's the only reference to Moore's Law in the entire article, and its a reasonable one. It puts into terms we can (just about) understand the implications of the discovery. Who knows what 1.5 * 10^220 bits of information processed is? But 600 years of development at the current rate is slightly more imaginable (although, I'll admit, only marginally so).
I haven't seen anything by Penrose which is like this. In fact, this article states an assumption ("consciousness is fundamentally computational in nature") that directly contradicts Penrose's most well known result, a rather dubious pseudo-mathematical "proof" that consciousness _cannot_ be computational as a consequence of Godel's Incompleteness Theorem.
So, no, it isn't really like Penrose's work.
Not commenting on the paper itself, but it has been submitted to PRL, not accepted. It hasn't gone through that wonderful process of peer-review that is the very heart of the scientific method (that and falsifiability but thats another topic). NASA has been setting a particularily bad example here with science by "press release". PRL is not an easy journal to publish in, lets wait until other experts have a look and not cheat the scientific method like this. PRL should not be mentioned in connection with this paper until this get published - Anyone can submit a paper to PRL...
Ummm.... no. Godel proved that the axiomatic system of Russel's PM allows the construction statements which can neccessarily neither be proven true nor proven false. There are other axiomatic systems that can be complete and consistent; IIRC it was in fact Godel who proved that the first-order propositional calculus is complete and fully consistent. Godel's fork only attaches to systems that allow the construction of statements about statements; many propositional systems (like the first-order propositional calculus) do not.
Oy.... where to start? Kant's Critique of Pure Reason is nothing but 600 pages describing how people distinguish intuition from fact (though admittedly Kant was using "intuition" in a sense that we don't normally use it today). Descartes wrote his Meditations as an attempt to remove "intuition" (again, closer to Kant's sense of the word than ours, but still) from philosophy. Plato, of course, says nothing about the subject directly but narrates several dialectical processes about the subject.
All's true that is mistrusted
Penrose in recent years isn't saying "consciousness isn't a computer." Rather in collaboration with Stuart Hameroff and a number of physicists is saying that "consciousness is a quantum computer."
/.'ers whose first reaction is: "He says we're not computers. Uncool!" consider the contrary reaction: "He says we're quantum computers. Way cool!" Also note that, as all /.'ers should know, quantum computers don't have the same limitations as conventional computers on capacity, thus the well-known threat they pose to encryption, being able to break it (in theory) in trivially short time periods.
So for all you
"with their freedom lost all virtue lose" - Milton