Enthusiasm is followed by disappointment and even depression, and then by renewed enthusiasm.

So the old Copenhagen interpretation needs to be generalized, needs to be replaced by something that can be used for the whole universe, and can be used also in cases where there is plenty of individuality and history.

Planets are too dim to be detected with existing equipment, far away, except in these very special circumstances where they're seen by their gravitational effect.

You know, there was a time, just before I started to study physical science, when astronomers thought that systems such as we have here in the solar system required a rare triple collision of stars.

If we look at the way the universe behaves, quantum mechanics gives us fundamental, unavoidable indeterminacy, so that alternative histories of the universe can be assigned probability.

Now, what that means is that there is fundamental indeterminacy from quantum mechanics, but besides that there are other sources of effective indeterminacy.

But when researchers at Bell Labs discovered that static tends to come from particular places in the sky, the whole field of radio astronomy opened up.

As a theoretical physicist, I feel at once proud and humble at the thought of the illustrious figures that have preceded me here to receive the greatest of all honors in science, the Nobel prize.

Hugh Everett's work has been described by many people in terms of many worlds, the idea being that every one of the various alternative histories, branching histories, is assigned some sort of reality.

Sometimes the probabilities are very close to certainties, but they're never really certainties.

Our planet doesn't seem to be the result of anything very special.

I have been interested in phenomena involving complexity, diversity and evolution since I was a young boy.

When you think you're listening to several conversations at once, they tell me, you may really simply be time sharing - that is, listening a little bit to this one, a little bit to that one.

For me, the study of these laws is inseparable from a love of Nature in all its manifestations.

Enthusiasm is followed by disappointment and even depression, and then by renewed enthusiasm.

I do not keep up with the details of particle physics.

I think also of my colleagues in elementary particle theory in many lands, and feel that in some measure I am here as a representative of our small, informal, international fraternity.

I am frequently astonished that it so often results in correct predictions of experimental results.

The chaos can act as a magnifier of quantum fluctuations so that they can produce sizable effects in the world around us. But we know that that can happen often.

But I don't actually adopt the point of view that our subjective impression of free will, which is a kind of indeterminacy behavior, comes from quantum mechanical indeterminacy.

We are driven by the usual insatiable curiosity of the scientist, and our work is a delightful game.

What I try to do in the book is to trace the chain of relationships running from elementary particles, fundamental building blocks of matter everywhere in the universe, such as quarks, all the way to complex entities, and in particular complex adaptive system like jaguars.

In fact any experiment that measures a quantum effect is one in which the quantum effect is aligned with the behavior of some heavy, macroscopic object; that's how we measure it.

If someone says that he can think or talk about quantum physics without becoming dizzy, that shows only that he has not understood anything whatever about it.

Well, I don't like to get involved in these philosophical issues very much.

Of course the word chaos is used in rather a vague sense by a lot of writers, but in physics it means a particular phenomenon, namely that in a nonlinear system the outcome is often indefinitely, arbitrarily sensitive to tiny changes in the initial condition.

Examples one finds in the philosophical literature are somebody who's seen the trial of a child of theirs, where they're being proved guilty of some crime that would drive the parent into a depression, maybe a suicidal depression.

Although I was not aware of it at the time, the experience of growing up during the Great Depression was to have a profound impact on my intellectual and professional career.

We had a booming stock market in 1929 and then went into the world's greatest depression. We have a booming stock market in 1999. Will the bubble somehow burst, and then we enter depression? Well, some things are not different.

In a strange way, I had fallen in love with my depression.

When I was in Philadelphia during the Depression in 1930 or '31, I got a very sad job as a night watchman in a garage. The cars in the garage had been abandoned by their owners, since they had lost their jobs and couldn't keep up the payments.

It is so often true that whether a person carries with him an atmosphere of gloom and depression or one of confidence and courage depends on his individual outlook.

This is what I am. I have periods of enormous self-destructive depression, where I go completely off my trolley and lose all sight of reality and reason.

Coming down off crack is like the worst depression. The worst.

Because its hard to realize now that that was the end of the great depression, you know. All of a sudden all of this is in front of me and I'm solvent, you know. I'm making some money and I know where my next meal is coming from, and I have a new pair of shoes and that's it.

So people have been hurting and I understand that. And it doesn't give them comfort or solace for me to tell them, you know, but for me, we would be in a worldwide depression.

You largely constructed your depression. It wasn't given to you. Therefore, you can deconstruct it.

The Great War proved how confused the world is. Depression is proving it again.

Good humor is a tonic for mind and body. It is the best antidote for anxiety and depression. It is a business asset. It attracts and keeps friends. It lightens human burdens. It is the direct route to serenity and contentment.

But with the slow menace of a glacier, depression came on. No one had any measure of its progress; no one had any plan for stopping it. Everyone tried to get out of its way.

As far as I was concerned, the Depression was an ill wind that blew some good. If it hadn't occurred, my parents would have given me my college education. As it was, I had to scrabble for it.

I prize the Depression, for instance, because I learned the value of things in the Depression that a way people who don't have to worry about such things never learned to prize it really, I believe.

At a time when going to college has never been more important, it's never been more expensive, and our nation's families haven't been in this kind of financial duress since the great depression. And so what we have is just sort of a miraculous opportunity simply by stopping the subsidy to banks when we already have the risk of loans. We can plow those savings into our students. And we can make college dramatically more affordable, tens of billions of dollars over the next decade.

Depression is when you have lots of love, but no one's taking.

Depression scares people off. It makes me laugh that it has that kind of effect.

The miserable failures of capitalist economies in the Great Depression were root causes of worldwide social and political disasters.

Depression, as far as I'm concerned, is just a waste of time.

I just think my body can't handle it any more. I did try a little drink a while back, and I was actually physically ill. I went into an immediate depression, and felt awful, just dreadful. So that's it. I'm over it now.

I felt very strongly the whole social impact of that depression, you know, and I felt very strongly about the efforts that this Resettlement Administration was trying to accomplish; resettling people, helping them, and so on.