“...This is one of the biggest technical challenges of our generation..If you look at almost every industry that is trying to solve really, really difficult technical challenges, the folks that tend to be involved are a little bit crazy and little bit optimistic. You need to have that optimism to get up every day and bang your head against the wall to try to solve a problem that has never been solved, and it’s not guaranteed that it ever will be solved.” (NYT, 24 May 21)