24 posts • joined Saturday 19th July 2008 10:33 GMT
Re: As Sir Roger Penrose pointed out years ago
I did read the book. It's unlikely that Penrose knows more about Gödel's theorem than I do - it's not his field, and it is mine. Your (vague) statement of the incompleteness theorem is incorrect, and your `argument' fails in the second line, because we can't see that the Gödel sentence is true - we can only see that either the Gödel sentence is true, or the theory is inconsistent. (The proof of incompleteness takes a theory T, constructs its Gödel sentence G, and then says EITHER G is true (and hence unprovable in T, because G says "G is not provable in T") OR G is false (in which case it is provable in T, and so T is inconsistent). Given any particular theory, we can't tell which of those is the case, because we have no way of determining whether a theory is consistent (except by using a different theory, which we then can't prove consistent...).
The formal statement of the theorem doesn't mention "truth" at all, because can't be pinned down in any reasonably powerful theory. It simply says there is a statement such neither the statement nor its negation can be proved by the theory.
So if you want to argue that humans are more powerful than computers, you need a more refined argument than that.
XEmacs has lots of vigorous comments, as you would expect from something on which Jamie Zawinski worked. Such as
/* #### urk urk urk!!! Chuck fix this shit! */
and then a few hundred lines later
/* #### Chuck fix this shit or I'm gonna scream! */
The comments are at least 15 years old, and Chuck (who is still around) still hasn't fixed them.
(#### is code for "major screwage that should be fixed for the next release")
There ain't no passive aggression in XEmacs!
Re: As Sir Roger Penrose pointed out years ago
Gawd. There should be a licence required to use the name of Gödel.
Penrose may have been a decent physicist, but as a logician he's what we in the trade call a "crackpot".
The incompleteness theorems say nothing at all about understanding, because understanding is not a mathematical concept. They merely say that any (suitably powerful and well-behaved) mathematical theory has things it can't prove. The incompleteness theorems themselves are NOT things that the system can't prove: they are proved in ordinary logic, and are no harder to understand than many other theorems.
just out of curiosity...
what do you call a female fanboi?
The importance of complexity
In a vigorous discussion about revising courses in a computer science degree, one of my colleagues opined that "every decent programmer is sometime going to come across a task that is NP-hard, so they need to know to tackle NP-hard problems".
I'm curious as to whether anybody on here (who is a programmer after going through a so-called top university's CS degree) has ever been asked to solve a task that is computationally intractable, and if so whether they used the last couple of decades' work on such things to solve it.
Come to that, how many CS graduates ever solve algorithmic problems, rather than systems engineering problems?
A biased sequence can still be random in some senses. The comment to which you reply is correct: all pseudo-random sequences are deterministic, because that's what the term means: a pseudo-random sequence is an algorithmically produced sequence which passes whatever your favourite statistical tests for randonmess are.
You're correct that non-determinism and randomness are different: in mathematical modelling of systems, a "non-deterministic" choice is one that is not made by the system of interest, but by its environment: e.g. a vending machine has a non-deterministic choice between receiving a "tea" button press and a "coffee" button press, as which one happens depends on the environment (the user). In theory of computation, a non-deterministic algorithm really means one where all possible choices are explored in parallel; or alternatively, you can take a lucky guess as to which choices you should make.
"Random" refers either to statistical properties of a sequence - and such a sequence can be a determined thing, just not determined by any computable function - or to a primitive notion of probability. In the probabilistic case, biased outputs are included: for example, if you generate a sequence of bits every second by seeing whether an atom of uranium has decayed in that second, that sequence is, as far as we know, truly random in every probabilistic sense of "random". The ratio of zeroes to ones, however, depends on how much uranium you have. In the algorithmic case, a biased sequence is not random becase it can be compressed - if the string has ten times as many zeroes as ones, then you can trivially compress it by coding sequences of zeroes, and you'll win - but it can still be a random sequence in the probabilistic sense.
Cryptographers want sequences that are random in both senses.
standard of proof for contempt
Para 2 of the judgement says "The law in relation to proof of contempt at common law is well settled. First the Attorney General must prove to the criminal standard of proof that the respondent had committed an act or omission calculated to interfere with or prejudice the due administration of justice"
Where does the bootnote statement about it being balance of probabilities come from?
perhaps ElReg should buy its contributors dictionaries?
"more paramount", indeed. That's even more nonsensical than "more unique".
Re: Is there another side?
Sigh. Apple did not file for a patent on rounded corners. It filed a registered design (in European terms, or a design patent in US terms) which is very different from a patent. It included seven characteristic features of the design, of which rounded corners formed one. The case was about whether Samsung's phone, *as a whole*, had been designed to look like Apple's registered design.
why not use an IDE
Because of the incredible bloat. I recently wanted to write a simple app for my ancient Nokia phone. I tried to do it The Right Way: downloading the entire Nokia development environment, and running under Wine (of course, doesn't work properly under Linux). Gigabytes of download, including a custom Eclipse; then you have to *run* Eclipse, which takes months to learn how to use (I've even taught using the damn thing, but have blissfully forgotten it all). After a few days of struggle, I thought, somebody must have done this the really right way - googled, and found a nice simple Makefile of a few lines that does everything. So now I can edit my tiny 600 line app in emacs like everything else, compile it with one command, and throw away the gigabytes of Eclipse and irrelevant Windows java libraries.
Re: Not a Troll
Emacs has had crypt mode, with automatic en/de-crypting of files on read and write, since 1988 at the latest. How does it do it? It adds a software module (crypt.el) to an electronic document management system (Emacs) which traps file i/o events (load, save) and applies crypto.
General encryption of *any* (non-setuid) Unix program by using LD_PRELOAD to hook into the file i/o at the system library level has been around since well before 1998.
And surely IBM have been hooking crypto into file i/o since the year dot?
Er, no, embassies remain the sovereign territory of the host country. Go read the Vienna Convention (or the implementing law).
In which case she has one smart donkey.
It can be a discourse marker rather than a grammatical marker. Seems to originate in Irish English. See Seamus Heaney's introduction to his Beowulf translation, where he translates the opening "Hwæt!" as "So!".
oh dear oh dear oh dear
Where did you get that graphic from? Four notational errors in one small table...
The W and Z bosons should be W and Z, not w and z; the photon should be γ (Greek gamma), not y (Latin y); and the neutrinos should be ν (Greek nu) not V (Latin V).
obvious to one skilled in the art?
From the "pithy description" quoted at the beginning of the ruling, this "invention"
looks like a bog standard look-up table, and is a trivial application of the maxim
"all problems in computer science can be solved by adding another level of indirection".
Knowing someone who once worked at the EPO, I know their quality control is utter crap;
but how did this get past even the dumbest examiner?
Posting of Friday 18th July 2008 23:05 GMT says:
>If you cant handle something as if it was RESTRICTED or less, then you
>typicallyneed to transport it with at least an armed guard, which is quite an
Oh yeah? As the CPS manual to which you helpfully provide a link says,
you can send SECRET documents in the Royal Mail, as long as you use
Special Delivery. I've never yet seen the postie turn up with an armed guard.
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