US economist Robert Gordon provoked debate last year when he claimed that invention was largely over, arguing that ‘all the important stuff’ had already been invented. This seemed to fly in the face of the regular announcement of revolutionary new technologies: from driverless cars and robot butlers through to multi-billion dollar apps and smart fridges. Yet a surprising number of voices echoed Gordon’s comments: after the rapid advancement of the twentieth century, when mankind went from first flight to moon landing in a few decades, the twenty-first century has seen lots of hype – and the occasional iPhone upgrade. Some have dubbed this era the Great Stagnation, where innovation has been reduced to tinkering around in the margins.

The debate raises an important question: what is the hallmark of a truly great invention? Leonardo is said to have ‘invented’ the helicopter, but you’d rather take a trip in Sikorsky’s models. The Pill was stumbled upon – as Carl Djerassi freely admitted – largely by accident. Some inventions are doomed to obsolescence or become victims of their own success: the age of penicillin is seemingly now giving way to the age of antibiotic resistance. At the same time, far more of us could name the inventor of the telephone than the mobile (Martin Cooper). Meanwhile, this year’s anniversary of the dropping of atomic bombs on Hiroshima and Nagasaki is a sobering reminder that not all great inventions have noble aims. Some say that the truly great inventions are intangible – literary critic Harold Bloom once claimed that Shakespeare ‘invented’ humanity – but patent offices tend not to agree.

Is an invention’s greatness a simple numbers game – lives saved or improved – or is it about how it transformed our knowledge of what is possible? In the age of nanotechnology, does size still matter? Should we laud those who came up with something first, those who perfected it or those who made it popular? Do we celebrate the collective effort of inventions developed over centuries or the individual genius who dreamed it to life? Join us for this balloon debate as we ask – what is the greatest invention?