Different writers at More Intelligent Life offer their own answers. Samantha Weinberg argues it is the Web. Edward Carr makes the case for the blade. Roger Highfield's candidate, the modern scientific method, is probably the answer I agree with most:
All great inventions rest on understanding how things work. And the greatest of all is the über-invention that has provided the insights on which other inventions depend: the modern scientific method, the realisation that we cannot grasp the way the world works by rational thought alone.
To gain meaningful insights into the scheme of things, logic has to be accompanied by asking probing questions of nature. To advance understanding, we need to devise rational conjectures and probe them to destruction through controlled tests, precise observations and clever analysis. The upshot is an unending dialogue between theory and experiment.
Unlike a traditional invention, the scientific method did not come into being at a particular time: its history is complex and stretches back long before 1833, when the term “scientist” was coined by the English polymath William Whewell. The method is not a concrete gadget like Gutenberg’s press, the computer or the Pill. Nor is it a brainwave like the non-geocentric universe, the Indo-Arab counting system or the theory of evolution. It is a fecund way of thinking on which the modern world rests. In relatively few generations, the rigorous application of the method has bootstrapped modern society through a non-linear accumulation of both knowledge and technology. Its impact on everyday life is ubiquitous and indisputable, even though a surprising number of people, including some senior politicians, have only a feeble grasp of its significance.via: 3 Quarks Daily and More Intelligent Life
