If you yell "fire" in a crowded theater where there is no fire, you have taken a safe situation and turned it into an immensely dangerous one.

If you yell "fire" in a crowded theater where there is a fire, you are attempting -- as best you can -- to mitigate the risk of an immensely dangerous situation.

The law prohibits shouting "fire" in a crowded theater where there is no fire present. There is no law against alerting your fellow patrons to the fact the building is on fire.

I agree with you. I get quite irritated when people in the UK tell me we should emulate them in gun control laws, healthcare laws, or their habit of dropping random 'u's in words where they clearly don't belong. Courtesy requires I refrain from telling the UK how they ought pattern their free speech laws on our First Amendment.

It is enough to say that I am pleased to live where I do, and that I believe the evils of generally-unregulated free speech are far far outweighed by the good.

Thank you for being a physician. Seriously. It's appreciated.

(-- would've been dead in the '90s except for someone like you)

The reason why progress has been so slow is because there is no one single disease, "cancer." Instead we have a few thousand different diseases which we collectively call cancer. Many of them look extremely similar, even to professional oncologists. First we have to identify all of these different cancers, and then we have to discover effective treatments against them. Some cancers will have common weaknesses; many (most?) do not.

There's a reason why cancer is called "the Emperor of Maladies". Cancer is probably the hardest scientific problem the human race has ever wrestled with. It makes the moon shot and the internet look like pikers by comparison.

Cancer is hard, and every day we don't have a cure more people are going to die in horrible ways. The first part makes us want to give up on cancer research, or to say that it's too hard, or to say that we haven't made any progress... but the second part will always keep us coming back to do more research and make another attempt.

My dream is that cancer might be cured in 100 years. I think it's a dream worth working for.

I'm reminded that when President Truman had his heart attack in 1956, the official prescription from his physician was bed rest accompanied by Mrs. Truman to keep him warm.

That was the whole, complete prescription.

Anyone who says medicine hasn't improved since 1952 simply isn't paying attention.

Not only am I from the United States (born in Iowa, currently live in Virginia), but I've spent enough time in emergency rooms (pursuant to EMT work) to know this is the law. Sorry, kid. :)

Check the bankruptcy declarations. The City of Detroit made various statements under penalty of perjury, and one of the most shocking was their admission that emergency response times averaged 58 minutes.

I can't explain the discrepancy between what Detroit says on a web site and what Detroit says in a courtroom. What I can do, though, is point you to my reference. :)

Mostly Detroit having been in a state of slow-motion collapse for 30+ years. Even the bankruptcy is caused by that -- it's not as if it suddenly came out of the blue.

30 years ago Detroit had 1.8 million people. Today it has about 700,000. A lot of businesses have also left, too. The city has spent 30 years acting as if nothing has really changed while the entire tax base has fled. Now the city is in a financial emergency of unthinkable proportions. Something like two-thirds of the ambulances have over 200,000 miles (320,000km) on them; there are 40% fewer police patrolling the streets than there were a decade ago; to save money, the city has shut off streetlights in something like half the city.

To make matters worse, half the city is functionally illiterate and thus can't find work in a modern economy. Unemployment in Detroit hovers around 50%.

Detroit's problems are the result of the city itself collapsing. The bankruptcy is just a symptom of the much bigger problems. Even if the federal government were to cut a $20 billion check to bail Detroit out of bankruptcy, these deeper problems would still exist.

Detroit is infamously bad, yeah. 58 minutes is the *official* Detroit response time. A few years ago I had to call the ambulance in Detroit for a neighbor who was having a stroke. We never found out what the response time was. We called the ER, who told us to bring her down ourselves. By the time we took her to the ER, sat with her through her diagnosis and admission and returned home, the ambulance *still* hadn't arrived. So I called 911 and canceled the ambulance call.

Where I come from, that's called "gross negligence" and "endangering lives".

I don't know where you are so I can't comment on your local laws. In the United States, it would likely be considered neither. Acts necessary to save human lives are neither criminally prosecutable nor subject to civil litigation.

The important word in that phrase, of course, being "necessary." Here's how a judge would evaluate your affirmative defense of, "Your honor, I had to drive like a madman: I had a man in obvious cardiac distress in the back of my car."

• First, did you have a reasonable belief the person was in extreme cardiac distress? "He was clutching his chest, short of breath, complaining of chest pains and having trouble remaining conscious. Okay, yes: the driver had a reasonable belief this individual was experiencing a life-threatening medical event and timely treatment was necessary."
• Second, was your action reasonable in light of the other options which were immediately available to you? "The defendant didn't bother to call an ambulance... then again, we *are* living in Detroit, where the response time to an emergency call hovers around one hour. His options were to either bring the guy to the hospital in his own vehicle, or attempt to provide cardiac care right there in the apartment. Transportation seems like a reasonable choice."
• Third, were unnecessary risks taken? "Sure, the guy was barrelling down Jefferson Avenue at 80 miles an hour. That was necessary. If he'd taken a detour and gone 80mph down a side street to hit a 7-11 along the way to buy a Slurpee, that would've been unnecessary... but he didn't do that, or anything like that."
• Fourth: if there was a reasonable belief someone's life is in jeopardy, if your action is reasonable in light of the options available to you, and if you avoided unnecessary risks, then brother, you are protected.

I am generally not a fan of urban driving. I own a Mustang GT and I go to the speedway whenever I can to race at high speeds in a controlled environment, but once I'm on public roads I obey the speed limit and I live in mortal fear of Suzy Homemaker in an SUV who's jawing on her cell phone instead of paying attention to her lane merge. I welcome the development of automated driving: for 99% of people it will be a massive step up in safety.

But let's not pretend that driving at 80mph in response to an immediate threat to a human life is something that we need to condemn. Those drivers amount to such a vanishingly small fraction of all accidents that I'm happy to give them a free pass. Go with God, may your tires have good tread, and I hope your passenger makes it.

Yes, the Halting problem is undecidable. That doesn't stop it from being NP-hard also.

Saying that it exists somewhere in NP-Hard may be technically true, in that NP-Hard encompasses all classes NP-Complete and harder (and UNDECIDABLE is definitely harder). But I don't know of a single reputable computer scientist who would characterize the Halting Problem as NP-Hard, in the same way that I don't know of a single one who would characterize 3SAT as being in EXPTIME. As my advisor once quipped, "That idea is too clever to be taken seriously."

Assuming one has an oracle is not the same thing as assuming one has a Turing machine that does something.

Clearly not, because if it were a Turing machine it wouldn't be allowed to exist. Hence the phrase, "hypercomputation." But if such an oracle could exist, it would mean P=NP simultaneous with P != NP, and that's just for starters -- a short list of the contradictions that would be forced to be true if any hypercomputational oracle existed is the sort of thing that will give mathematicians nightmares. This is why virtually the whole field of computer science believes that hypercomputational oracles cannot exist, and why a significant fraction believes that any line of reasoning that involves a hypercomputational oracle is invalid because it starts from a false premise -- that such a thing can exist.

And no, Davis is not condemning people trying to do real hypercomputation. He's condemning the entire field of hypercomputation as a discipline.

No. The Halting Problem belongs to class UNDECIDABLE, not class NP-Hard. I admire your attempt at rationalizing it, but Alan Turing proved this to the world's satisfaction. If you wish to prove the Halting Problem does not belong to UNDECIDABLE then you're going to have an uphill road to hoe. If you still believe the Halting Problem belongs to NP-Hard, I would suggest you begin by correcting its Wikipedia article.)

Your argument involving an oracle that solves the Halting Problem is absurd because you're assuming the existence of hypercomputation -- and if such an oracle could exist, then we would simultaneously have P=NP and P != NP. Martin Davis has gone so far as to declare hypercomputation both "a myth" and "a nonexistent discipline." Those are strong words coming from one of the brightest lights in the field of computational theory and computational complexity.

It's a bedrock principle of logic that if you start from a false proposition anything can be proven. You assume the existence of an oracle that can solve the Halting Problem. This is a false proposition. Anything can be proven once you make oracular assumptions.

At this point I'm pretty sure you're trolling. The Halting Problem is UNDECIDABLE -- it exists in a complexity class considerably beyond what is normally thought of as 'NP-Hard'.

And if you don't understand my parenthetical remark, well... that should be taken as a sign that your computational theory is seriously lacking. The meaning is quite clear to someone who has a proper understanding of what complexity class NP-Hard is about.

Goodbye, troll.

No, even then your characterization of NP-Hard is incorrect.

"A class of problems is NP-Hard if being able to solve it in polynomial time..."

If you can solve it in polynomial time, then it's in P. Even under your revised definition, you're implicitly arguing that P=NP, because that's the only way you can solve an NP-Hard problem in polynomial time. (And even then, you would only be able to solve the NP-Complete subset of NP-Hard.)

Permit me to stand for a moment on my all-but-dissertation Ph.D. in theoretical computer science:

You're wrong.

Sorry, but the original poster was essentially correct. Your definition would make sense if it involved the existence of a polynomial-time transformation between an NP-Complete problem and the purported NP-Hard problem, but saying that "a solution to an NP-Hard problem allows for NP to be solved in polynomial time" is ... febrile. If an NP-Complete problem can be solved in polynomial time, then P=NP. Since we believe P != NP, your claim would mean NP-Hard problems would have no solutions, which would mean they would really belong to class UNDECIDABLE, and... etc. I don't think you meant to go there.

With respect to the OP's talk about direction, I understood that to be a layman's distinction between solution and verification. If that was the OP's intent then he's guilty of at most an infelicitous choice of words -- he's not "at best confused, and essentially wrong."