Behind it all is surely an idea so simple, so beautiful, that when we grasp it - in a decade, a century, or a millennium - we will all say to each other, how could it have been otherwise? How could we have been so stupid?

I like to say, when asked why I pursue science, that it is to satisfy my curiosity, that I am by nature a searcher trying to understand. If you haven't found something strange during the day, it hasn't been much of a day.

It was the defining event and remains a thousand degrees hot.

Every heat engineer knows he can design his heat engine reliably and accurately on the foundation of the second law [of thermodynamics]. Run alongside one of the molecules, however, and ask it what it thinks of the second law. It will laugh at us. It never heard of the second law. It does what it wants. All the same, a collection of billions upon billions of such molecules obeys the second law with all the accuracy one could want

We all know that the real reason universities have students is in order to educate the professors.

Spacetime tells matter how to move; matter tells spacetime how to curve.

It is my opinion that everything must be based on a simple idea. And it is my opinion that this idea, once we have finally discovered it, will be so compelling, so beautiful, that we will say to one another, yes, how could it have been any different.