The boldness of asking deep questions may require unforeseen flexibility if we are to accept the answers.

Sometimes attaining the deepest familiarity with a question is our best substitute for actually having the answer.

Physicists are more like avant-garde composers, willing to bend traditional rules... Mathematicians are more like classical composers.

We might be the holographic image of a two-dimensional structure.

I have long thought that anyone who does not regularly - or ever - gaze up and see the wonder and glory of a dark night sky filled with countless stars loses a sense of their fundamental connectedness to the universe.

How can a speck of a universe be physically identical to the great expanse we view in the heavens above?

No matter how hard you try to teach your cat general relativity, you're going to fail.

We can certainly go further than cats, but why should it be that our brains are somehow so suited to the universe that our brains will be able to understand the deepest workings?

If the theory turns out to be right, that will be tremendously thick and tasty icing on the cake.

A unified theory would put us at the doorstep of a vast universe of things that we could finally explore with precision.

String theory has the potential to show that all of the wondrous happenings in the universe - from the frantic dance of subatomic quarks to the stately waltz of orbiting binary stars; from the primordial fireball of the big bang to the majestic swirl of heavenly galaxies - are reflections of one, grand physical principle, one master equation.

My mom says: 'Why aren't you a doctor?' and I'm like, 'I am a doctor!' and she's all, 'No, I mean a real doctor.' She reads my books, but she says they give her a headache.

My emotional investment is in finding truth. If string theory is wrong, I'd like to have known that yesterday. But if we can show it today or tomorrow, fantastic.

Our eyes only see the big dimensions, but beyond those there are others that escape detection because they are so small.

Supersymmetry is a theory which stipulates that for every known particle there should be a partner particle. For instance, the electron should be paired with a supersymmetric 'selectron,' quarks ought to have 'squark' partners, and so on.

We know that if supersymmetric particles exist, they must be very heavy; otherwise we would have spotted them by now.

String theory envisions a multiverse in which our universe is one slice of bread in a big cosmic loaf. The other slices would be displaced from ours in some extra dimension of space.

Physics grapples with the largest questions the universe presents. 'Where did the totality of reality come from?' 'Did time have a beginning?'

Intelligence is the ability to take in information from the world and to find patterns in that information that allow you to organize your perceptions and understand the external world.

I would say in one sentence my goal is to at least be part of the journey to find the unified theory that Einstein himself was really the first to look for.

We're on this planet for the briefest of moments in cosmic terms, and I want to spend that time thinking about what I consider the deepest questions.

The idea that there could be other universes out there is really one that stretches the mind in a great way.

I think it's too fast to say that all sci-fi ultimately winds up having some place in science. On the other hand, imaginative minds working outside of science as storytellers certainly have come upon ideas that, with the passing decades, have either materialized of come close to materializing.

I may be a Jewish scientist, but I would be tickled silly if one day I were reincarnated as a Baptist preacher.

The melded nature of space and time is intimately woven with properties of light speed. The inviolable nature of the speed of light is actually, in Einstein's hands, talking about the inviolable nature of cause and effect.

The bottom line is that time travel is allowed by the laws of physics.

Most scientists like to operate in the context of economy. If you don't need an explanatory principle, don't invoke it.

There's no way that scientists can ever rule out religion, or even have anything significant to say about the abstract idea of a divine creator.

Science is very good at answering the 'how' questions. 'How did the universe evolve to the form that we see?' But it is woefully inadequate in addressing the 'why' questions. 'Why is there a universe at all?' These are the meaning questions, which many people think religion is particularly good at dealing with.

The universe is incredibly wondrous, incredibly beautiful, and it fills me with a sense that there is some underlying explanation that we have yet to fully understand. If someone wants to place the word 'God' on those collections of words, it's OK with me.

It's hard to teach passionately about something that you don't have a passion for.

I think the relationship between memory and time is a very deep and tricky one, to tell you the truth. I don't consider memory another sense. I do consider memory that which allows us to think that time flows.

Every moment is as real as every other. Every 'now,' when you say, 'This is the real moment,' is as real as every other 'now' - and therefore all the moments are just out there. Just as every location in space is out there, I think every moment in time is out there, too.

I'd say many features of string theory don't mesh with what we observe in everyday life.

In my own research when I'm working with equations, I never feel like I really understand what I'm doing if I'm solely relying on the mathematics for my understanding. I need to have a visual picture in my mind. I'm constantly translating from the math to some intuitive mind's-eye picture.

In any finite region of space, matter can only arrange itself in a finite number of configurations, just as a deck of cards can be arranged in only finitely many different orders. If you shuffle the deck infinitely many times, the card orderings must necessarily repeat.

Over the centuries, monumental upheavals in science have emerged time and again from following the leads set out by mathematics.

When you buy a jacket, you pick the size to ensure it fits. Similarly, we live in a universe in which the amount of dark energy fits our biological make-up. If the amount of dark energy were substantially different from what we've measured, the environmental conditions would be inhospitable to our form of life.

Many different planets are many different distances from their host star; we find ourselves at this distance because if we were closer or farther away, the temperature would be hotter or colder, eliminating liquid water, an essential ingredient for our survival.

Einstein's theory of relativity does a fantastic job for explaining big things. Quantum mechanics is fantastic for the other end of the spectrum - for small things.

String theory is the most developed theory with the capacity to unite general relativity and quantum mechanics in a consistent manner. I do believe the universe is consistent, and therefore I do believe that general relativity and quantum mechanics should be put together in a manner that makes sense.

To tell you the truth, I've never met anybody who can envision more than three dimensions. There are some who claim they can, and maybe they can; it's hard to say.

The number of e-mails and letters that I get from choreographers, from sculptors, from composers who are being inspired by science is huge.

Oftentimes, if you're talking to a seasoned interviewer who asks you a question, they may do a follow-up if they didn't quite get it. It's rare that they'll do a third or fourth or fifth or sixth follow-up, because there's an implicit, agreed-upon decorum that they move on. Kids don't necessarily move on if they don't get it.

The absolute worst thing that you ever can do, in my opinion, in bringing science to the general public, is be condescending or judgmental. It is so opposite to the way science needs to be brought forth.

Art makes us human, music makes us human, and I deeply feel that science makes us human.

The fact that I don't have any particular need for religion doesn't mean that I have a need to cast religion aside the way some of my colleagues do.

For me it's been very exciting to contribute to the public's understanding of how rich and wondrous science is.

When we benefit from CT scanners, M.R.I. devices, pacemakers and arterial stents, we can immediately appreciate how science affects the quality of our lives.

Science is a way of life. Science is a perspective. Science is the process that takes us from confusion to understanding in a manner that's precise, predictive and reliable - a transformation, for those lucky enough to experience it, that is empowering and emotional.