Chemistry, until my childhood, not that long ago, was regarded as a calculating device. Because you couldn’t reduce to physics. So it’s just some way of calculating the result of experiments. The Bohr atom was treated that way.

We seem gradually to be groping toward an understanding of the world of subatomic particles, but we really do not know how far we have yet to go in this task.

I have nothing new to teach the world. Truth and Non-violence are as old as the hills. All I have done is to try experiments in both on as vast a scale as I could.

It always seems odd to me that the fundamental laws of physics, when discovered, can appear in so many different forms that are not apparently identical at first, but, with a little mathematical fiddling, you can show the relationship.

Chemistry can be a good and bad thing. Chemistry is good when you make love with it. Chemistry is bad when you make crack with it.

There happen to be a lot of people around who spent an hour on the Internet and think they know a lot of physics, but it doesn’t work like that… There’s a reason there are graduate schools in these departments.

My first popular book, ‚A Brief History of Time,‘ aroused a great deal of interest, but many found it difficult to understand.

OK, so what’s the speed of dark?

The first amazing fact about gravitation is that the ratio of inertial mass to gravitational mass is constant wherever we have checked it. The second amazing thing about gravitation is how weak it is.

I tell you the solemn truth, that the doctrine of the Trinity is not so difficult to accept for a working proposition as any one of the axioms of physics.

In some sort of crude sense, which no vulgarity, no humor, no overstatement can quite extinguish, the physicists have known sin; and this is a knowledge which they cannot lose.

Today, all physicists know from studying Einstein and Bohr that sometimes an idea which looks completely paradoxical at first, if analyzed to completion in all detail and in experimental situations, may, in fact, not be paradoxical.

The missing link in cosmology is the nature of dark matter and dark energy.

It is indeed a matter of great difficulty to discover, and effectually to distinguish, the true motions of particular bodies from the apparent because the parts of that immovable space, in which those motions are performed, do by no means come under the observation of our senses.

Today’s scientists have substituted mathematics for experiments, and they wander off through equation after equation, and eventually build a structure which has no relation to reality.

There were several possible solutions of the difficulty of classical electrodynamics, any one of which might serve as a good starting point to the solution of the difficulties of quantum electrodynamics.

I need physics more than friends.

M-theory is the unified theory Einstein was hoping to find.

From the point of view of basic physics, the most interesting phenomena are, of course, in the new places, the places where the rules do not work – not the places where they do work! That is the way in which we discover new rules.

The good thing about having chemistry is, when you get to the improv section of a scene, you’ve got somebody to feed off. It can go on and on and on, and the sky’s the limit.

With the exception of gravitation and radioactivity, all of the phenomena known to physicists and chemists in 1911 have their ultimate explanation in the laws of quantum electrodynamics.

My father was a research scientist in tropical medicine, so I always assumed I would be a scientist, too. I felt that medicine was too vague and inexact, so I chose physics.

The internal machinery of life, the chemistry of the parts, is something beautiful. And it turns out that all life is interconnected with all other life.

It is reasonable that forces directed toward bodies depend on the nature and the quantity of matter of such bodies, as happens in the case of magnetic bodies.

It should be possible to explain the laws of physics to a barmaid.

We get the exciting result that the total energy of the universe is zero. Why this should be so is one of the great mysteries – and therefore one of the important questions of physics. After all, what would be the use of studying physics if the mysteries were not the most important things to investigate?

We are certainly not to relinquish the evidence of experiments for the sake of dreams and vain fictions of our own devising; nor are we to recede from the analogy of Nature, which is wont to be simple and always consonant to itself.

I constructed a laboratory in the neighborhood of Pike’s Peak. The conditions in the pure air of the Colorado Mountains proved extremely favorable for my experiments, and the results were most gratifying to me.

When I was a young man, Dirac was my hero. He made a breakthrough, a new method of doing physics. He had the courage to simply guess at the form of an equation, the equation we now call the Dirac equation, and to try to interpret it afterwards.

I think the discovery of supersymmetric partners for the known particles would revolutionize our understanding of the universe.

Before 1915, space and time were thought of as a fixed arena in which events took place, but which was not affected by what happened in it. Space and time are now dynamic quantities… space and time not only affect but are also affected by everything that happens in the universe.

There is nothing that living things do that cannot be understood from the point of view that they are made of atoms acting according to the laws of physics.

Because there is a law such as gravity, the universe can and will create itself from nothing.

Man can be understood only by ascending from physics, chemistry, biology, and geology. In other words, he is first of all a cosmic problem.

Physics has a history of synthesizing many phenomena into a few theories.

Gravitation is, so far, not understandable in terms of other phenomena.

The best and safest method of philosophizing seems to be first to inquire diligently into the properties of things, and establishing those properties by experiments, and then to proceed more slowly to hypotheses for the explanation of them.

My background educationally is physics and economics, and I grew up in sort of an engineering environment – my father is an electromechanical engineer. And so there were lots of engineery things around me.

I tend to approach things from a physics framework. And physics teaches you to reason from first principles rather than by analogy.

Everything starts somewhere, although many physicists disagree.

The drawing teacher has this problem of communicating how to draw by osmosis and not by instruction, while the physics teacher has the problem of always teaching techniques, rather than the spirit, of how to go about solving physical problems.

Working out another system to replace Newton’s laws took a long time because phenomena at the atomic level were quite strange. One had to lose one’s common sense in order to perceive what was happening at the atomic level.

Just as the system of the sun, planets and comets is put in motion by the forces of gravity, and its parts persist in their motions, so the smaller systems of bodies also seem to be set in motion by other forces and their particles to be variously moved in relation to each other and, especially, by the electric force.

You have a row of dominoes set up; you knock over the first one, and what will happen to the last one is that it will go over very quickly.

I went to Princeton specifically to study physics.

There are children playing in the streets who could solve some of my top problems in physics, because they have modes of sensory perception that I lost long ago.

No one undertakes research in physics with the intention of winning a prize. It is the joy of discovering something no one knew before.

There is no physical law precluding particles from being organised in ways that perform even more advanced computations than the arrangements of particles in human brains.

Quarks came in a number of varieties – in fact, at first, only three were needed to explain all the hundreds of particles and the different kinds of quarks – they are called u-type, d-type, s-type.

The greatest progress is in the sciences that study the simplest systems. So take, say, physics – greatest progress there. But one of the reasons is that the physicists have an advantage that no other branch of sciences has. If something gets too complicated, they hand it to someone else.

I had a project for my life which involved 10 years of wandering, then some years of medical studies and, if any time was left, the great adventure of physics.

In the past, there was active discrimination against women in science. That has now gone, and although there are residual effects, these are not enough to account for the small numbers of women, particularly in mathematics and physics.

They say the universe is expanding. That should help with the traffic.

It is theoretically possible to warp spacetime itself, so you’re not actually moving faster than the speed of light, but it’s actually space that’s moving.

The same thing is to be understood of all bodies, revolved in any orbits. They all endeavour to recede from the centres of their orbits, and were it not for the opposition of a contrary force which restrains them to and detains them in their orbits, which I therefore call Centripetal, would fly off in right lines with a uniform motion.

While physics and mathematics may tell us how the universe began, they are not much use in predicting human behavior because there are far too many equations to solve. I’m no better than anyone else at understanding what makes people tick, particularly women.

Often one postulates that a priori, all states are equally probable. This is not true in the world as we see it. This world is not correctly described by the physics which assumes this postulate.

I think equation guessing might be the best method to proceed to obtain the laws for the part of physics which is presently unknown. Yet, when I was much younger, I tried this equation guessing, and I have seen many students try this, but it is very easy to go off in wildly incorrect and impossible directions.

There could be no fairer destiny for any physical theory than that it should point the way to a more comprehensive theory in which it lives on as a limiting case.

Science predicts that many different kinds of universe will be spontaneously created out of nothing. It is a matter of chance which we are in.

Because the theory of quantum mechanics could explain all of chemistry and the various properties of substances, it was a tremendous success. But still there was the problem of the interaction of light and matter.