Life is all about experiences - good and bad. But what if a machine could make you feel nothing but happiness. Would you plug into it?
How do you feel about your life? Happy, miserable or somewhere in-between? Are you stressed at having to pay the bills, at the state of your relationship, about your health, the kids, your job?
Imagine you could hook into a machine and all that stress would magically dissipate. The well-known Harvard philosopher, Robert Nozick, once asked us to imagine what he called the Experience Machine.
"Suppose there were an Experience Machine that would give you any experience you desired. Superduper neuropsychologists could stimulate your brain so that you would think and feel you were writing a great novel, or making a friend, or reading an interesting book. All the time you would be floating in a tank, with electrodes attached to your brain," he wrote.
While you were hooked into the machine you wouldn't know the experiences you believed you were having weren't real, you'd think they were all actually occurring.
Just think, you could pre-programme the machine so you would end up really thinking you looked like a Hollywood star, had won the Nobel Prize for physics, enjoyed a fulfilling marriage, scored the victorious goal in the World Cup final and lived in a penthouse overlooking the sea. Would you plug into such a machine?
Nozick was not the only person to imagine such a contraption. About the time he was writing Anarchy, State and Utopia, the book in which the Experience Machine appears, film-maker Woody Allen was directing his movie Sleeper. It featured the Orgasmatron - no further explanation required.
There are many literary precursors too. In Aldous Huxley's Brave New World there is a hallucinogenic called soma which gives you a marvellous combination of a high, minus any hangover.
Science fiction has continued to play with similar scenarios. The 1999 movie, The Matrix, depicts a sinister world in which unbeknown to them people are living in a simulated reality.
We may be some way off from inventing an Experience Machine, but for thousands of years there have been substances available that make us feel happier, if only temporarily.
The Experience Machine raises some fundamental questions, questions that have been addressed by philosophers from Aristotle to Jeremy Bentham and John Stuart Mill. What do we value in life? Is a life of struggle in any way superior to one of easy, instant solutions?
What does it mean to have an "authentic" as opposed to a "fake" experience? Is pleasure what matters or should we have a wider conception of what makes a life go well?
But these are not issues merely for armchair philosophers. The evidence suggests there is no simple link between economic growth and happiness. As a result more and more politicians, like British Prime Minister David Cameron and French President Nicolas Sarkozy, want policies to be directed not merely at gross domestic product (GDP), but at increasing what is sometimes called general well-being (GWB).
By doing this both France and Britain are following the lead of the tiny Himalayan kingdom of Bhutan, which has long quantified its level of happiness. But targeting GWB demands some conception and agreement about what should count as happiness, or well-being - and that requires some hard philosophy.
In Cameron's case at least he studied philosophy at university. It may be a case of dusting off his old text books and taking another look.