Once we had Newton's law of gravity though, we knew the distance, radius, mass, and even surface gravity of the moon. Would you say it's fair to say that by then we knew in principle we could go there and walk there?

(P.S. I assume you know this but the way you wrote your comment makes it seem like our measurements of lunar distance are nearly as inaccurate as Hipparchus's, when we actually know it down to the millimeter (thanks to retroreflectors placed by Apollo, actually). The wide variation from 55x to 64x Earth's radius is because it changes over the course of the moon's orbit, due to [edit: primarily its elliptical orbit, and only secondarily] the Sun and Jupiter's gravity.)

I am of course not saying you're wrong that "we don't know". We obviously don't know. It's possible, just like it's possible that we could discover cheap free energy (fusion?) tomorrow and then be in a post-scarcity utopia. But that's worth taking about as seriously as the possibility that we'll discover AGI tomorrow and be in a Terminator dystopia, or also a post-scarcity utopia.

More importantly, it's a distraction from the very real, well-past-imminent problems that existing dumb AI has, such as the surveillance economy and misinformation. OpenAI, to their credit, does a good job of taking these existing problems quite seriously. They draw a strong contrast to MIRI's AI alarmism.

Have you ever read idlewords? Best writing I know of on this subject: https://idlewords.com/talks/superintelligence.htm