Aristotle thought the low-hanging fruit had been picked in his time. (I didn't keep the original quote, but it said roughly that most important knowledge that c

Aristotle thought the low-hanging fruit had been picked in his time. (I didn't keep the original quote, but it said roughly that most important knowledge that could be figured out probably would be within a few lifetimes.) This may be accurate in delimited fields like fundamental physics (though even there you have to wonder when you reflect on e.g. the half-century between Turing and Deutsch/Feynman with no one picking up quantum computing). But our understanding of nature is so tiny compared to what's out there. We're only a small percentage of the way to understanding even our own biology in full. Why would the frontier of available discoveries become much poorer, relative to our abilities if deployed well, long before useful discoveries run out? Maybe they really do, and we won't really know until we can look back much later, but it's not how I'd bet.