Imagine, says Harvard professor Michael Sandel, that you are a shipwrecked sailor, adrift in a lifeboat without food or water.
Is it morally permissible to kill and eat the cabin boy to ensure your own survival?
Prof Sandel poses the philosophical question to about 1000 students packed into Harvard's Sanders Theatre, a magnificent, three-tiered lecture room that oozes history through every wooden panel. But these days he is also talking to a much bigger audience - the 4.6 million people who have watched this televised lecture on YouTube and the tens of thousands who go on to follow his free and massively popular justice course on the web. Students around the globe have voted on the fate of Parker the cabin boy, who was murdered by two English sailors in 1884, but judged a necessary sacrifice by 40% of Prof Sandel's online audience.
Courses like this are known as Moocs (Massive open online courses). These days, anyone with a good broadband connection can use them to learn direct from the world's most prestigious professors and universities, usually without paying a cent. Most offer online discussion between students and use a computer program or fellow students to award marks, as each course averages about 33,000 students.
New Zealand dipped its toe in the water this week with the launch of a computer studies course from Waikato University, following years of anxious speculation that this could be a replay of the late 1990s dotcom bubble.
There has certainly been a lot of hype. Time magazine declared 2012 ''the year of the Mooc'' and British author Michael Barber, a former educational adviser to Tony Blair, described online tertiary education as an avalanche that would fundamentally alter the landscape for universities.
But nagging questions persist. Why would any serious student do a peer-graded Mooc instead of a real university course? Will the quality of education be up to scratch? And how will anyone involved make money when the product is free?
The questions have not disappeared but the search for answers has become more urgent, especially in the United States where politicians have decided Moocs could be a lifesaver for a tertiary education system drowning in student debt.
The term ''Mooc'' was coined in 2008 but took off in 2011 when two Stanford University professors, Sebastian Thrun and Peter Norvig, put their ''Introduction to Artificial Intelligence'' course online, free of charge. Unlike Prof Sandel's slickly produced video, this was a home-made geeky affair, consisting of a whiteboard, a voiceover and lots of quick quizzes. It had 160,000 students from day one.
Thrun and Norvig promptly left Stanford to set up Udacity, a company that teaches mainly computer science and maths to about 400,000 students and promises to fix America's ''broken'' higher education system. Harvard and the Massachusetts Institute of Technology responded with the not-for-profit edX, which boasts more than one million students and some of the world's top-ranked universities. Both are dwarfed by the global leader Coursera, which has enjoyed phenomenal growth to more than 4.7 million students taking 442 free courses with 87 university partners worldwide.
Other countries are trying to catch up. Britain's Open University has formed an online provider called FutureLearn, due to go live this month with 21 university partners, and six of Australia's leading eight universities are now offering free online education.
The head of Massey's teaching and learning centre, Prof Mark Brown, says the university has carefully chosen the courses to showcase what Massey is good at.
''It might be the very reason why they go on to complete a master's degree with more specialisation, as a result of one free course.''
He has a simple answer to other universities still worrying about whether to join in or hold back on free online courses.
''We've taken the view that if we're not exploring and innovating within the Mooc playpen, then we're really not in a position to understand what the opportunities are. Sitting on the sidelines can take you only so far.''
Reaction to the Mooc phenomenon among many university academics has ranged from scepticism to horror, with Prof Sandel and the ethics of cannibalism centre-stage. In April, San Jose State University announced it would include his EdX Justice course as part of its teaching programme, prompting a revolt by philosophy professors who refused to use it. The course is now being taught through the English department.
Associate philosophy professor Karin Brown told the Harvard University newspaper The Crimson that this confirmed their worst fears.
''Eventually, you will only have facilitators for those courses ... It's a very cheap way to solve the budget problem of public universities, but you are creating a university without professors.''
Otago University vice-chancellor Harlene Hayne summed up local scepticism in an editorial in the university's magazine in January. She argued that education was more than a knowledge transfer from teacher to student, it was the development of skills such as communication and critical thinking, which relied on human contact. Hands-on experience, such as laboratory experiments for science students, was essential. Prof Hayne also noted that more than 90% of students who signed up for free online courses did not complete them, probably, she suggested, because they got bored.
After exhaustive research, she had concluded that ''the concept of the Mooc will not displace the traditional university experience and the business case for the future of Moocs actually hangs by a thread''.
Waikato University professor Michael Peters, who specialises in the politics of education, shares Prof Hayne's reservations but disagrees with her conclusion. He predicts online tertiary education will be unstoppable because, as the US experience shows, the financial incentives to extend it are so strong.
''You look at student loans in America. It's just passed the US$1 trillion ($NZ1.22 trillion) mark. It's supposed to blow out by another US$1.4 trillion in 10 years. That's the largest form of debt apart from housing mortgage.''
Prof Peters believes the Mooc movement has been taken over by governments with an agenda to cut costs in tertiary education and introduce privatisation. He makes a distinction between most of the early courses, which grew out of an idealistic open education movement, and the profit-driven ''industrial broadcast model''.
The first type is more interactive and uses extensive social media. Students partly determine what they learn, which can mean the course changes each time. The second is similar to a television broadcast, often featuring a celebrity speaker who imparts information to tens or even hundreds of thousands of students simultaneously.
To Prof Peters and other educationalists, this echoes the attempts of last century to beam in TV and radio lessons to underdeveloped countries. He contrasts this one-way teaching method with the traditional Oxford-Cambridge university model, which relies on skilled tutors working with small groups of students.
Prof Mark Brown says Massey is well aware of these pitfalls and will avoid the old-fashioned video dump.
''A lot of effort has gone into how to create videos that are truly interactive,'' he says.
''One of the criticisms of Moocs that Massey was very mindful of was taking 1960s-style teaching and putting it on 21st-century networks and claiming this is somehow new and revolutionary.''
He says testing will involve written answers, not just multi-choice questions, marked by real people. Science students will carry out experiments in a simulated lab. Open2Study has also rethought some of the much-touted advantages of early Moocs, including learning at your own pace, which has been linked to the high drop-out rate. Tutors will check students' progress to make sure they don't fall away.
As for Prof Hayne's comments, Prof Brown says face-to-face contact is important ''but I think we need to be careful that we don't put a gold standard on traditional ways of teaching. I don't really think that in the type of world we live in today sitting in a lecture theatre with 400 or 500 students is what we would see as an effective model of learning.''
For US-born Massey business lecturer and digital learning enthusiast Dennis Viehland, Moocs represent an opportunity to revolutionise not just online education but university teaching in general. He says some lecturers are already ''flipping the classroom'' by giving their students Mooc-style video lectures to watch at home, so they can discuss the issues in class time.
He lists several online teaching innovations including:
• replacing the traditional 50-minute lecture with a 12/15-minute interactive video
• tutorials in the form of online discussion forums, using social media techniques (so the most ''liked'' student answer goes to the top)
• instant feedback on computer-marked answers - highly appealing for the video-game generation
• students marking each other, which some academics hate but Assoc Prof Viehland says is supported by research showing their grades closely match the teachers'.
Moocs also allow providers to crunch huge amounts of data to see how students really learn, then adapt course materials and teaching methods accordingly. Coursera, which raised US$43 million from venture capital investors in July, is using this technological advantage to market its courses to universities trying to develop their own online offerings. Like many entertainment and news providers, it is also developing an optional paid subscription to bring in some much-needed revenue.
''But the big question nobody's been able to answer is, how are universities going to make money out of this?'' says Prof Viehland.
''Why should we give away something for free for which we have traditionally charged? That's the way the music business and the newspaper business have gone, to their detriment.''
The answer may lie at Georgia Technical Institute, which will next year offer an online master's degree in computer science for $US6600 ($NZ8026), a fraction of the usual $US45,000. Other universities have tried and failed to charge for online courses before but Georgia Tech's computer science department is among the best in America, so the experiment has the potential to change the way tertiary education is delivered. Students can choose to do the course as a free Mooc or pay for tutoring, student support and the chance to sit online exams for a recognised qualification.
''It could be epoch-making,'' Obama's science and technology adviser S. James Gates jun told the New York Times.
''If it really works, it could begin the process of lowering the cost of education.''
For many academics this is code for lower pay and lost jobs but Prof Viehland thinks these fears are misplaced, as most joiners so far have been students in undeveloped countries and professionals looking to add to their skills.
''Moocs have the opportunity to grow the pie, not just slice it differently,'' he argues.
''So they won't replace university-based education.''
Meanwhile, he's looking forward to next month's The Kennedy Half Century, the Mooc world's most spectacular offering to date. It has stunning video with Hollywood production values, a superstar presenter in US political commentator Prof Larry J. Sabato and a tie-in to Sabato's book and TV series on the same subject.
Prof Viehland is picking the due date for the final assignment could even be the 50th anniversary of Kennedy's assassination on November 22, 1963. History purists should probably look away now.