WHAT WOULD it be worth to society to have a treatment for Alzheimer’s that actually worked — and via portable, noninvasive technology? Or a radically low-cost method for early detection of cancer, or Ebola, or Zika, that was as quick and simple as a home-pregnancy test? Or an ingestible robot that enabled surgery with no incision? How about grid-scale batteries that would make solar energy more dependable than the sun? Or carbon-free energy from nuclear power that was inherently meltdown-proof? Or biodegradable plastics made without fossil fuels?