The impossible is often, almost every time, untried. - Peter Diamandis

Greenblatt is not alone in this assertion. Many believe water is an issue of money and will be best solved locally, and without the aid of techie gizmos. It's an opinion based on hindsight. The last century saw governments dithering while they searched for a high-tech, silver-bullet solution. Millions died in the interim, and the world is full of gadgets either unsuitable for the ruggedness of their deployment area or impossible to maintain because supply chains did not extend far enough.

Lightwave, another emotional-computing startup, can capture not just the emotional state of an individual, but that of a whole crowd. It's already been utilized by Cisco to judge a startup pitch competition, helped DJ Paul Oakenfold increase listener engagement at a concert in Singapore, and measured viewer reactions during a pre-screening of The Revenant.

Physics training is a good framework for reasoning," explains Musk. "It forces you to boil things down to their most fundamental truths and then connect those truths in a way that lets you understand reality. This gives you a way to attack the counterintuitive, a way of figuring out things that aren't obvious. When you're trying to create a new product or service, I think it's critical to use this framework for reasoning. It takes a lot of mental energy, but it's still the right way to do it.