The seat of consciousness is in the brain. If that goes, all other aspects that made that person who he is is gone. By that definition brain dead = dead.
What if you just take the brain out and digitize it? Or use some fancy time machine to make an exact copy of someone who was dead for a few thousand years? We're talking about technological advances, not the status quo, after all.
You're either dead or you're not. It's rather binary. There's no continuum.
By your definition, I'm assuming you mean "death" is an irreversible change to a "living" body. How do you know that a change is absolutely irreversible? That's the basic problem with a binary definition.
how do you prove that the formal specification is what the customer wanted, and how do you prove that the code actually implements the design?
It's just as hard to prove that a hacked together piece of kludge is what the customer wanted. The customer is always wrong.
Formal verification of code with regard to a formal specification requires a programmatic proof verifier that can examine both the code and the specification and use formal logic to prove their equivalence. A proof of correctness for the verifier itself is handy; it can verify its own correctness with regard to its own formal specification, which ultimately must be verified by humans (or by some simpler automated proof system that's easier to verify).
I've seem automatic testing products that claim to do both, but in order to make them work you have to specify every variable and every line of code as the "requirements", then compare what the tool thinks the result should be to the output of the program.
Typical snobbery. As long as you're learning the theory, why shouldn't you do something practical?
If you're learning the theory, why can't you just apply it to any programming language of your choice? The hard part of computer science is not the mapping between the theory and a particular implementation of a programming language. That was sort of the point of the article.
The fact that you refer to it as a "C++" data structures course belies your problem; data structures (and algorithms) are language neutral. You should be able to take any formalization of a language equivalent to a turing machine and implement the same data structures and algorithms that you can in C++. That is the sole meaning of computer science, as far as I'm concerned.
I think Dijkstra's basic hypothesis is that the user interface IS the problem. Most people don't understand computers, and trying to turn computers into appliances via simple user interfaces is, in the end, rather silly from a computer science point of view. From a normal person's point of view, they have some magic device that helps them in some way if they invoke it properly. Dijkstra's goal is for humanity in general to abandon "magic" and focus on fundamentally understanding computers.
Like Java or flash, it shouldn't matter where an executable comes from; the operating system should make it safe to execute by restricting what it can do. Give it no rights to the network, file system, and limited ability to draw things to the screen by default, and only allow privilege escalation by well defined user interface dialogs, and even then never a blanket permission to read or write to the entire file system, or to open up an unlimited number of network connections, or draw fake security dialog boxes on the screen.
What is this, 1980 when a DOS program had full control over the entire computer? It's 2008, and it should be slightly easier to do real privilege separation.
You don't buy a game, you buy a license to have an electronic replica of your brain inserted into some company's server to play a game entirely on their terms, and that copy can never, ever leave. This completely protects the intellectual property of the game's publisher.
Buy a copy, then download a warez version, and install the warez version. Send a physical letter to the manufacturer with the UPC from the box and the receipt, and explain that you had to download the warez version in order to keep your computer stable. Scan the whole thing before you send it, and put it on the Internet for everyone else to see so they can't ignore it.
If you actually pay for their product and still go to the trouble of installing a warez version without DRM, that will send a much stronger message than pirating or not buying the game at all.
Prop 8 is the will of the people, picking on the Mormons won't make you right, it just makes you a bigoted jerk.
Well, technically it's the will of a slight majority of the people in a state, about a law affecting a small minority in that state, and further a law that has absolutely no direct legal impact on the non-gay majority, except perhaps some retarded idea of "brand dilution". I think that's why sensible people are annoyed.
It's even better than that! A SNAKE, possessed by the DEVIL, talked a woman into talking a man into eating an apple a few thousand years ago.
Not only that, but a snake that didn't crawl on its belly. I don't know if it was supposed to have feet or fly or what, but it was probably quite a bit happier before that.
Logic exists, but can you measure it ? For that matter, can you measure the United States, the saying "you reap what you seed" and the meme "Do not want" ? And once you've done that, you could continue by measuring communism, capitalism and nationalism.
Logic can be formalized and then quantified via Godel numbering or an equivalent scheme. Once quantified, it can be measured in any way desirable. Probably the most useful notion of measurement in logic is the measure of a statement's truth or falsity. Specifically, prepositional calculus contains statements of prepositions joined with 'and', 'or', 'not', 'implies', and 'equivalence' (e.g. A -> B, B->C, therefore A->C, and A->B ~B->~A), with a universal deterministic method of determining if any well formed statement is true or false. In that sense, the entire language of prepositional calculus can be measured to determine the truth or falsehood of any statement. Predicate calculus and first (and higher) order logic are similarly quantifiable in a formal system and thus measurable. For instance, the number of logical statements in any formalized logic is at most the cardinality of the natural numbers. Any other well defined measure you can come up with can probably be answered.
The U.S. can obviously be measured by land area, maximum length of a chord of a great circle on the Earth's surface, the maximum distance between two points in threespace, etc. You could also measure the demographics of its citizens, or any number of other things.
The saying "you reap what you seed" has 22 letters, 5 words, and one sentence. The meme "Do not want" has 412,000,000 Google results. Communism, capitalism, and nationalism are all words that must, in general, be measured in terms of other words. That's what a dictionary is for. If you want to measure the economic or political results of those theories, use statistics.
The concept of existence is itself too ill-defined to be useful here. We don't actually live in a world of matter and hard facts, we each live in our very own shadowy realm of dreams. Those dreams affect our behavior, so they exist in one sense, but they aren't physical objects, so they don't exist in another. I believe this is the case with "soul": it isn't a physical object, but rather an abstract concept.
You argue that all humans live in a shadowy realm of dream, yet you claim to know something of "physical objects." Aren't you just assuming the existence of real physical objects without evidence? What more can you be sure of than that your thoughts exist, and in that case, why not simply start from that point for defining existence and extend it to the existence of an external reality that you sense? In that case, existence is very well defined within your own mind; it is simply that which you can think about. Philosophically, this allows you to avoid arguing from a baseless assumption that there exists some "real" reality that you can only partially sense, but know exists.
Now, as for the soul, it's obvious that the definition of soul is what matters, not the existential nature of any specific definition. To most people, their soul is an integral part of their mind and body and is generally where they experience thoughts, emotions, and/or sensations. In such a vague description there is obviously truth; every conscious person experiences thoughts, emotions, and sensations and can arguably locate their own experience (or subset of experiences) of them in one place, the soul. Scientifically, this is synonymous with the mental activity of the nervous system. If the definition of the soul involves supernatural properties or abilities, then its definition is ill-defined, since no method of scientifically testing the definition exists.
I don't think that the soul is an abstract concept any more than happiness, sadness, love, or other mental properties are abstract. They really happen, and therefore exist, and likewise the soul as experience-of-the-mind exists as a real thing in
$1,000,000 in extortion to extract a promise "not to reveal any patient information...yet" or $1,000,000 to hire private investigators and/or a hit man. The latter is far more effective.
Perfect altruism is useless in evolutionary terms. If every organism sacrificed itself to save another organism whenever possible, none would survive except the ones that were not perfectly altruistic. Some self interest ("greed") is necessary.
Greed is beneficial as long as the greedy individual can keep what he or she obtains. Greedy individuals can better support their offspring, who generally share their greedy genes. The balance between greed and altruism basically depends on the general wisdom of society. The more altruistic people are, the more greedy people can benefit, but the less altruistic people are, the less they benefit from cooperation. A stable point is where there is just enough altruism and greed to consume all the available resources without too many people getting upset and changing the gene pool with a shotgun.
It's not "subjecting others to your religion". It's denial, and it's an important part of voluntary human relations. It simply doesn't matter if religion is behind it. Forcing doctors to perform procedures against their will is slavery.
A license to become a doctor or pharmacist implies putting the patient's interests first and following well established medical guidelines. If abortion, birth control, or euthanasia is what the patient wants, the *licensed* professions had better do their job or lose their license.
Would you license an engineer who wouldn't walk under ladders or go to the 13th floor to perform inspections, or who insisted the best way to keep a bridge standing was by throwing salt over his shoulder every day? Licensed professionals denying birth control is just as silly.
It's no worse than standard mathematics done by humans. There's no indication that humans can present a proof of a theorem that says it has no proof (for instance, can you prove "this statement has no proof of its truth" is true or false or neither?), so humans are no more powerful than a formal system in which one can construct Godel's incompleteness proof.
Specifically, I'm sure that the "central" theorems they're referring to are ones nearest to set theory or some other basic set of axioms. It's much harder to prove Fermat's last theorem or the Poincare Conjecture with complete formalism than it is to prove simple theorems of arithmetic. Once the central theorems are proven, it is simpler to tackle more complex theorems using the already proven theorems as lemmas.
A mere comment about priorities, relative importance of issues, and so forth. In any case, I was not the only one to make such a comment.
Frankly, mathematics is more important than any other issue. You just fail to realize the practical applications that mathematics has in everyone's life. The most basic reason that anyone on earth has a standard of living above that of hunter gatherers is because of mathematics; knowing seasons and how to plant crops relied on rudimentary mathematics, and modern farming relies on advanced chemistry and biology, which have as their basis the mathematics of stoichiometry and statistics. Not to mention engineering which makes heavy use of mathematics and physics in order to create the machines necessary for our massive population.
In short, I'd rather see advances in mathematics than I would the elimination of world hunger; without further mathematical and scientific discoveries, even nations with plenty will just exhaust their resources and revert to poverty and starvation.
Once servers are virtualized it becomes trivial to run only the number of virtual servers necessary to handle the load. Cloud computing, in essence. A truly distributed model of computing would work just as well, but my guess is that will only arrive sometime after most servers are already virtualized.
The only impact shutdown and startup should have is on hard disks; all other electronics should take millions of power cycles without any problems as long as the power supplies are gentle. Hard disks for virtual servers would generally live in a SAN anyway, and powering down sections of the SAN would be possible. Some drives already support a low RPM standby mode that lowers power consumption without the danger of cold startups that wear out the spindle motor. And really, shutting hard drives down completely at night and starting them up in the morning would put less load on them than most laptop drives, which already last a couple years at least in a much worse physical environment.
In regard to point 3: Do you also own everything in an inverted pyramidal solid originating at the center of the earth and extending through your property boundaries to the edge of the visible universe? Or are there some practical limits to "owning" things that flow across property lines?
My guess is that you're actually drinking your neighbors' water, and your own water has flowed over to your neighbors as well. Several times. Same with all the air you "own." Do low pressure weather fronts count as a capital loss because of the lower air density over your property?
Come on, it's dead simple and it's safe. Just install a page fault handler and mark all the pages of the DLL as being unavailable, examine the current thread state of all processes and mark them if they are currently executing in the unavaiable pages, and if so simply return success from the page fault handler until the thread leaves the locked region (essentially single step through the DLL until it finally returns to the caller). If a thread was not originally executing in the protected pages and enters it, just stall it. Once all threads are stalled or not accessing the locked pages, patch the DLL and mark the pages available and uninstall the page fault handler.
What could possibly go wrong? Only if the data structures that the DLL uses internally are modified will this be difficult, in which case the patched DLL will just have to convert its own data during the patch time. If changes to user data structures are required, then the patched DLL would have to burn some space in each new data structure to identify it as a patched version and treat it appropriately, while detecting the old data structures reliably. That might be a little harder than the general case, but not impossible.
Is getting 0wned something you would want to happen on a production server that can't have downtime?
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The seat of consciousness is in the brain. If that goes, all other aspects that made that person who he is is gone. By that definition brain dead = dead.
What if you just take the brain out and digitize it? Or use some fancy time machine to make an exact copy of someone who was dead for a few thousand years? We're talking about technological advances, not the status quo, after all.
You're either dead or you're not. It's rather binary. There's no continuum.
By your definition, I'm assuming you mean "death" is an irreversible change to a "living" body. How do you know that a change is absolutely irreversible? That's the basic problem with a binary definition.
how do you prove that the formal specification is what the customer wanted, and how do you prove that the code actually implements the design?
It's just as hard to prove that a hacked together piece of kludge is what the customer wanted. The customer is always wrong.
Formal verification of code with regard to a formal specification requires a programmatic proof verifier that can examine both the code and the specification and use formal logic to prove their equivalence. A proof of correctness for the verifier itself is handy; it can verify its own correctness with regard to its own formal specification, which ultimately must be verified by humans (or by some simpler automated proof system that's easier to verify).
I've seem automatic testing products that claim to do both, but in order to make them work you have to specify every variable and every line of code as the "requirements", then compare what the tool thinks the result should be to the output of the program.
Automatic testing is not formal verification.
Things wrong with your post:
0) you don't understand numbering schemes.
1) you don't understand computer scientists.
2) you insulted dijkstra.
The 2nd is by far the worst, the 1st is understandable, but the 0th is where your problem started.
Typical snobbery. As long as you're learning the theory, why shouldn't you do something practical?
If you're learning the theory, why can't you just apply it to any programming language of your choice? The hard part of computer science is not the mapping between the theory and a particular implementation of a programming language. That was sort of the point of the article.
The fact that you refer to it as a "C++" data structures course belies your problem; data structures (and algorithms) are language neutral. You should be able to take any formalization of a language equivalent to a turing machine and implement the same data structures and algorithms that you can in C++. That is the sole meaning of computer science, as far as I'm concerned.
What about a ^= b, b ^= a, a ^= b (for integers)?
I think Dijkstra's basic hypothesis is that the user interface IS the problem. Most people don't understand computers, and trying to turn computers into appliances via simple user interfaces is, in the end, rather silly from a computer science point of view. From a normal person's point of view, they have some magic device that helps them in some way if they invoke it properly. Dijkstra's goal is for humanity in general to abandon "magic" and focus on fundamentally understanding computers.
Like Java or flash, it shouldn't matter where an executable comes from; the operating system should make it safe to execute by restricting what it can do. Give it no rights to the network, file system, and limited ability to draw things to the screen by default, and only allow privilege escalation by well defined user interface dialogs, and even then never a blanket permission to read or write to the entire file system, or to open up an unlimited number of network connections, or draw fake security dialog boxes on the screen.
What is this, 1980 when a DOS program had full control over the entire computer? It's 2008, and it should be slightly easier to do real privilege separation.
In 2032:
You don't buy a game, you buy a license to have an electronic replica of your brain inserted into some company's server to play a game entirely on their terms, and that copy can never, ever leave. This completely protects the intellectual property of the game's publisher.
Buy a copy, then download a warez version, and install the warez version. Send a physical letter to the manufacturer with the UPC from the box and the receipt, and explain that you had to download the warez version in order to keep your computer stable. Scan the whole thing before you send it, and put it on the Internet for everyone else to see so they can't ignore it.
If you actually pay for their product and still go to the trouble of installing a warez version without DRM, that will send a much stronger message than pirating or not buying the game at all.
Prop 8 is the will of the people, picking on the Mormons won't make you right, it just makes you a bigoted jerk.
Well, technically it's the will of a slight majority of the people in a state, about a law affecting a small minority in that state, and further a law that has absolutely no direct legal impact on the non-gay majority, except perhaps some retarded idea of "brand dilution". I think that's why sensible people are annoyed.
It's even better than that! A SNAKE, possessed by the DEVIL, talked a woman into talking a man into eating an apple a few thousand years ago.
Not only that, but a snake that didn't crawl on its belly. I don't know if it was supposed to have feet or fly or what, but it was probably quite a bit happier before that.
Well, technically the rocks in the desert covered it already.
And math is just an emergent property of simple rules defined over sets of strings.
Logic exists, but can you measure it ? For that matter, can you measure the United States, the saying "you reap what you seed" and the meme "Do not want" ? And once you've done that, you could continue by measuring communism, capitalism and nationalism.
Logic can be formalized and then quantified via Godel numbering or an equivalent scheme. Once quantified, it can be measured in any way desirable. Probably the most useful notion of measurement in logic is the measure of a statement's truth or falsity. Specifically, prepositional calculus contains statements of prepositions joined with 'and', 'or', 'not', 'implies', and 'equivalence' (e.g. A -> B, B->C, therefore A->C, and A->B ~B->~A), with a universal deterministic method of determining if any well formed statement is true or false. In that sense, the entire language of prepositional calculus can be measured to determine the truth or falsehood of any statement. Predicate calculus and first (and higher) order logic are similarly quantifiable in a formal system and thus measurable. For instance, the number of logical statements in any formalized logic is at most the cardinality of the natural numbers. Any other well defined measure you can come up with can probably be answered.
The U.S. can obviously be measured by land area, maximum length of a chord of a great circle on the Earth's surface, the maximum distance between two points in threespace, etc. You could also measure the demographics of its citizens, or any number of other things.
The saying "you reap what you seed" has 22 letters, 5 words, and one sentence. The meme "Do not want" has 412,000,000 Google results. Communism, capitalism, and nationalism are all words that must, in general, be measured in terms of other words. That's what a dictionary is for. If you want to measure the economic or political results of those theories, use statistics.
The concept of existence is itself too ill-defined to be useful here. We don't actually live in a world of matter and hard facts, we each live in our very own shadowy realm of dreams. Those dreams affect our behavior, so they exist in one sense, but they aren't physical objects, so they don't exist in another. I believe this is the case with "soul": it isn't a physical object, but rather an abstract concept.
You argue that all humans live in a shadowy realm of dream, yet you claim to know something of "physical objects." Aren't you just assuming the existence of real physical objects without evidence? What more can you be sure of than that your thoughts exist, and in that case, why not simply start from that point for defining existence and extend it to the existence of an external reality that you sense? In that case, existence is very well defined within your own mind; it is simply that which you can think about. Philosophically, this allows you to avoid arguing from a baseless assumption that there exists some "real" reality that you can only partially sense, but know exists.
Now, as for the soul, it's obvious that the definition of soul is what matters, not the existential nature of any specific definition. To most people, their soul is an integral part of their mind and body and is generally where they experience thoughts, emotions, and/or sensations. In such a vague description there is obviously truth; every conscious person experiences thoughts, emotions, and sensations and can arguably locate their own experience (or subset of experiences) of them in one place, the soul. Scientifically, this is synonymous with the mental activity of the nervous system. If the definition of the soul involves supernatural properties or abilities, then its definition is ill-defined, since no method of scientifically testing the definition exists.
I don't think that the soul is an abstract concept any more than happiness, sadness, love, or other mental properties are abstract. They really happen, and therefore exist, and likewise the soul as experience-of-the-mind exists as a real thing in
$1,000,000 in extortion to extract a promise "not to reveal any patient information...yet" or $1,000,000 to hire private investigators and/or a hit man. The latter is far more effective.
Perfect altruism is useless in evolutionary terms. If every organism sacrificed itself to save another organism whenever possible, none would survive except the ones that were not perfectly altruistic. Some self interest ("greed") is necessary.
Greed is beneficial as long as the greedy individual can keep what he or she obtains. Greedy individuals can better support their offspring, who generally share their greedy genes. The balance between greed and altruism basically depends on the general wisdom of society. The more altruistic people are, the more greedy people can benefit, but the less altruistic people are, the less they benefit from cooperation. A stable point is where there is just enough altruism and greed to consume all the available resources without too many people getting upset and changing the gene pool with a shotgun.
It's not "subjecting others to your religion". It's denial, and it's an important part of voluntary human relations. It simply doesn't matter if religion is behind it. Forcing doctors to perform procedures against their will is slavery.
A license to become a doctor or pharmacist implies putting the patient's interests first and following well established medical guidelines. If abortion, birth control, or euthanasia is what the patient wants, the *licensed* professions had better do their job or lose their license.
Would you license an engineer who wouldn't walk under ladders or go to the 13th floor to perform inspections, or who insisted the best way to keep a bridge standing was by throwing salt over his shoulder every day? Licensed professionals denying birth control is just as silly.
It's no worse than standard mathematics done by humans. There's no indication that humans can present a proof of a theorem that says it has no proof (for instance, can you prove "this statement has no proof of its truth" is true or false or neither?), so humans are no more powerful than a formal system in which one can construct Godel's incompleteness proof.
Specifically, I'm sure that the "central" theorems they're referring to are ones nearest to set theory or some other basic set of axioms. It's much harder to prove Fermat's last theorem or the Poincare Conjecture with complete formalism than it is to prove simple theorems of arithmetic. Once the central theorems are proven, it is simpler to tackle more complex theorems using the already proven theorems as lemmas.
A mere comment about priorities, relative importance of issues, and so forth. In any case, I was not the only one to make such a comment.
Frankly, mathematics is more important than any other issue. You just fail to realize the practical applications that mathematics has in everyone's life. The most basic reason that anyone on earth has a standard of living above that of hunter gatherers is because of mathematics; knowing seasons and how to plant crops relied on rudimentary mathematics, and modern farming relies on advanced chemistry and biology, which have as their basis the mathematics of stoichiometry and statistics. Not to mention engineering which makes heavy use of mathematics and physics in order to create the machines necessary for our massive population.
In short, I'd rather see advances in mathematics than I would the elimination of world hunger; without further mathematical and scientific discoveries, even nations with plenty will just exhaust their resources and revert to poverty and starvation.
Once servers are virtualized it becomes trivial to run only the number of virtual servers necessary to handle the load. Cloud computing, in essence. A truly distributed model of computing would work just as well, but my guess is that will only arrive sometime after most servers are already virtualized.
The only impact shutdown and startup should have is on hard disks; all other electronics should take millions of power cycles without any problems as long as the power supplies are gentle. Hard disks for virtual servers would generally live in a SAN anyway, and powering down sections of the SAN would be possible. Some drives already support a low RPM standby mode that lowers power consumption without the danger of cold startups that wear out the spindle motor. And really, shutting hard drives down completely at night and starting them up in the morning would put less load on them than most laptop drives, which already last a couple years at least in a much worse physical environment.
In regard to point 3: Do you also own everything in an inverted pyramidal solid originating at the center of the earth and extending through your property boundaries to the edge of the visible universe? Or are there some practical limits to "owning" things that flow across property lines?
My guess is that you're actually drinking your neighbors' water, and your own water has flowed over to your neighbors as well. Several times. Same with all the air you "own." Do low pressure weather fronts count as a capital loss because of the lower air density over your property?
Come on, it's dead simple and it's safe. Just install a page fault handler and mark all the pages of the DLL as being unavailable, examine the current thread state of all processes and mark them if they are currently executing in the unavaiable pages, and if so simply return success from the page fault handler until the thread leaves the locked region (essentially single step through the DLL until it finally returns to the caller). If a thread was not originally executing in the protected pages and enters it, just stall it. Once all threads are stalled or not accessing the locked pages, patch the DLL and mark the pages available and uninstall the page fault handler.
What could possibly go wrong? Only if the data structures that the DLL uses internally are modified will this be difficult, in which case the patched DLL will just have to convert its own data during the patch time. If changes to user data structures are required, then the patched DLL would have to burn some space in each new data structure to identify it as a patched version and treat it appropriately, while detecting the old data structures reliably. That might be a little harder than the general case, but not impossible.
Is getting 0wned something you would want to happen on a production server that can't have downtime?