Lived in a barrel in the Athens marketplace. Famous for stunts such as carrying an oil lamp in daylight, saying "I'm looking for an honest man". Once, Alexander the Great, the king that had conquered the known world, visited Diogenes and asked if there was anything he could do for him. To which Diogenes replied "For the present, that you stand a little out of my sun".
Took lots of precise stellar measurements in a purpose-built observatory – by eye, before telescopes were invented!
Tycho wanted to combine what he saw as the geometrical benefits of Copernican heliocentrism with the philosophical benefits of the old Ptolemaic system into his own model of the universe.
His precise measurements indicated that "new stars" (stellae novae, now called supernovae), in particular that of 1572 (SN 1572), lacked the parallax expected in sublunar phenomena and were therefore not tail-less comets in the atmosphere, as previously believed, but were above the atmosphere and beyond the Moon. Using similar measurements, he showed that comets were also not atmospheric phenomena, as previously thought, and must pass through the supposedly immutable celestial spheres.
May have attended Schelling's lectures at the same time as Søren Kierkegaard.
Scott Alexander on Marx:
I know that “capitalists sometimes do bad things” isn’t exactly an original talking point. But I do want to stress how it’s not equivalent to “capitalists are greedy”. I mean, sometimes they are greedy. But other times they’re just in a sufficiently intense competition where anyone who doesn’t do it will be outcompeted and replaced by people who do. Business practices are set by Moloch, no one else has any choice in the matter.
(from my very little knowledge of Marx, he understands this very very well and people who summarize him as “capitalists are greedy” are doing him a disservice)
Wanted to show that God had created the heavenly bodies according to a regular, beautiful, symmetric design. Went through the observations of Tycho Brahe, postulated an increasing number of circles in Mars' orbit, until he had got it down – but it was a complicated theory. There were small errors ascribable to measurement, and thankfully Kepler did not want to believe that Brahe had measured imperfectly, so he kept working until in desperation he postulated an elliptical orbit. This fit perfectly!
Before, everyone assumed the orbits were circles – even if you had to give the planets many different circular orbits they could be in at different times. Shaping it as an ellipse enabled there to be only one orbit. But few people took such a thing as an elliptical orbit seriously – it seemed too imperfect for heavenly bodies.
He explained the elliptical orbit to Galileo himself, who rejected it. Now we accept it as Kepler's First Law.
