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Comment by erulabs | Hacker News Reader

The more I learn about Kepler the more I believe that he alone advanced humanity several decades or possibly centuries. His incredible drive to prove his own theory, and then his ability to put that theory down and to match one to the evidence, oh man. I've loved his story since the Carl Sagan Cosmos episode on him sniped me as a kid, but I get just as excited about it in videos like these (part one of this series explains how Kepler determined the orbits of the planets).

If you want to be deeply inspired, read about his life, his book Somnium, what happened to his mother. It's all so profoundly motivating.

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I agree, and if you want to learn more about him I highly recommend this two-part series: https://www.youtube.com/watch?v=Phscjl0u6TI

What is particularly wild is that Kepler had to wait for Tycho Brahe to die to steal his data before Brahe's heirs got their hands on it. Not only that, but Kepler was very close to making epicycles work but he was not satisfied with the (relatively small) predictive errors. So, if not for Kepler's combination of...flexible morality and unsatified nature, physics as we know it would have been delayed or perhaps never discovered at all!

The important thing is to be self aware enough to clearly differentiate between good and bad, even when doing bad stuff sometimes could be beneficial.

The same thought occurred to me, but then I realized we still don't know if his discovery was beneficial. I don't think we'll know that until humanity spreads life beyond Earth and avoids killing the biosphere in a number of innovative ways (bathing it in nuclear fire being perhaps the most relevant to this discussion). It's only possible to excuse the millions of lives that ended in pain and death during the many wars we've had since industrialization, itself driven by scientific understanding, if there really is light at the end of the tunnel. Otherwise, I can't help but think we'd have been better off living in small, low-tech hamlets at the teetering edge of the natural world, filled with wrong but comforting ideas about the heavens.

By the time Kepler published his work, Copernicus had already developed the heliocentric model, and Galileo was starting to gather significant observational evidence for heliocentrism (and had begun developing the principles of mechanics).

Kepler made a huge contribution to the development of physics, but "the new physics" was already in motion by the time he published his work, and I think it's an exaggeration to say progress of physics would have stopped without Kepler.

>By the time Kepler published his work, Copernicus had already developed the heliocentric model

The heliocentric model was an old idea anyway(Aristarchus), what Copernicus did was not that impresive since it was wrong.

It was an old idea that had been out of favor for two millennia.

> what Copernicus did was not that impresive since it was wrong

What a statement. Copernicus was more right than anyone else of his time. His model revolutionized astronomy and led to the development of modern physics.

Kepler’s half-insight, half-inferential-leap that the orbits were ellipses and not just off-center circles (made possible by the fantastic quality of the data Brahe gathered—he didn’t even have a telescope, remember) was very important to Newton’s positing the law of universal gravitation. (The universal part is much more important here, as far as a naturalist’s worldview is concerned, than the gravitation one.) See Arnold’s writings regarding just how tiny the difference is between the two possibilities.

Would Kepler’s absence have stopped scientific progress? Probably not. But some very, very important parts of it would not have proceeded as they did.

Maybe even more importantly, he dropped his preferred theory of fitting the orbits of known planets (at the time) with Platonic solids. That requires iron commitment to science.

Or listen to the opera about his mothers trial: https://en.wikipedia.org/wiki/Kepler_(opera)

Besides the Cosmos episode, do you have any recommendations on learning more?

"Blind watchers of the sky" is one of the best presentations of Kepler's and Galileo's oeuvre I have ever read. (I am an astrophysicist, but this book can be read by non-specialists too.)

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