Quotes from Thomas Levenson

there's a common trick nature plays on its would-be investigators: resemblance, the human urge to map the unknown onto the already known, can be a snare. Just because something looks like something else doesn't mean that the backstory for both must be the same. Rocks scattered across the sky may appear to be a rubble field left behind by an explosion…but unless you stop to think how else you might get there, you rely on assumptions not in evidence.

Le Verrier left the solar system larger than he found it - one both better and less completely understood.

The enterprise of making sense of the material world turns on a key question: what happens when something observed in nature doesn't fit within the established framework of existing human knowledge?

As Vulcan's troublesome history reveals, no one gives up on a powerful, or a beautiful, or perhaps simply a familiar and useful conception of the world without utter compulsion – and a real alternative.

But now, in the daily business of our warped cosmos, Vulcan barley registers, even as an antiquarian curiosity. Only a few have some vague memory of the story – mostly physicists and astronomers with a historical bent. For them, Vulcan is a cautionary tale: it's so damn easy to see what one wants or expects to find.

THERE HE REMAINED for almost two years, cut off from every other scholar or mathematician. The isolation suited him. "In those days," he would recall half a century later, "I was in the prime of my age for invention & minded Mathematics & Philosophy more than at any time since.

As late as 1742, London hatters beat to death a man who dared shape headgear without having gone through the apprentice system.

Science is unique among human ways of knowing because it is self-correcting. Every