Quotes from Leonard Susskind

The principles are exactly the same as those of QED: everything is built out of propagators, vertex diagrams, and coupling constants. But there are new actors and whole new plot lines, including one called QCD.

At some point we have to give up and say that's just the way it is. Or, not give up and push on.

Between successive measurements along the z axis, we turn through 90 degrees, make an intermediate measurement, and turn it back to its original direction. Will a subsequent measurement along the z axis confirm the original measurement? The answer is no. The

The three-dimensional world of ordinary experience––the universe filled with galaxies, stars, planets, houses, boulders, and people––is a hologram, an image of reality coded on a distant two-dimensional surface

one of the key features of a black hole: different observers have paradoxically different perceptions of the same events. To

Quantum mechanics can be appreciated, to some degree, on a purely qualitative level. But mathematics is what brings its beauty into sharp focus. We have tried to make this amazing body of work fully accessible to mathematically literate nonphysicists.

the world seems filled with people who are genuinely, deeply interested in physics but whose lives have taken them in different directions. This book is for all of us.

There are more things in heaven and earth, Horatio, Than are dreamt of in your philosophy. —WILLIAM SHAKESPEARE, HAMLET

Is the universe 'elegant,' as Brian Greene tells us? Not as far as I can tell, not the usual laws of particle physics, anyway. I think I might find the universal principles of String Theory most elegant - if I only knew what they were.

You are a victim of your own neural architecture which doesn't permit you to imagine anything outside of three dimensions. Even two dimensions. People know they can't visualise four or five dimensions, but they think they can close their eyes and see two dimensions. But they can't.

I was from a poor Jewish family in the South Bronx. My father was a plumber, but when I was 16, he got sick and I had to take over. Being a plumber in the South Bronx wasn't fun.