If there were something that truly moves you, it would be curiosity and the desire to know new things, Worlds, and experience.

Curiosity is born with you and it stays throughout your entire life: the moment that you feel that there is nothing that motivates you to keep learning, you have a problem.

Old age starts where curiosity ends!

We associate youth with vitality and the desire to enjoy the World without limits.

We associate old age with contentment with life and the loss of appetite to discover more about the things around us …

Children have a desire to know extremes. They are filled with an energy that moves them to question everything, to want everything, and to touch everything.

They are growing, and they want to know where they are and what it is that life has to offer them.

It is in this exact way that we have also learned to maintain our constant curiosity, the kind that moves us and leads us to overcome challenges.

It is that which makes us feel young, makes us feel more like children.

The World is strange. The whole universe is very strange, but you see when you look at the details and you find out that the rules of the game are very simple – the mechanical rules by which you can figure out exactly what is going to happen when the situation is simple. It is like a chess game.

If you are in a corner with only a few pieces involved, you can work out exactly what is going to happen, and you can always do that when there are only a few pieces.

And yet in the real game there are so many pieces that you can’t figure out what is going to happen – so there is a kind of hierarchy of different complexities.

It is hard to believe. It is incredible! In fact, most people don’t believe that the behavior of, say, me is the result of lots and lots of atoms all obeying very simple rules and evolving into such a creature that a billion years of life has produced.

There is such a lot in the World. There is so much distance between the fundamental rules and the final phenomena that it is almost unbelievable that the final variety of phenomena can come from such a steady operation of such simple rules.

Do you have to build the most complex scaffolding to find out the simple rules? But it is not complicated. It is just a lot of it. And if you start at the beginning, which nobody wants to do – I mean, you come in to me now for an interview, and you ask me about the latest discoveries that are made.

Nobody ever asks about a simple, ordinary phenomenon in the street. What about those colors? We could have a nice interview, and I could explain all about the colors, butterfly wings, the whole big deal.

But you don’t care about that. You want the big final result, and it is going to be complicated because I am at the end of 400 years of a very effective method of finding things out about the World.

It has to do with curiosity. It has to do with people wondering what makes something do something. And then to discover, if you try to get answers, that they are related to each other – that things that make the wind make the waves, that the motion of water is like the motion of air is like the motion of sand.

The fact that things have common features. It turns out more and more universal. What we are looking for is how everything works. What makes everything work.

But it is curiosity as to where we are, what we are. It is very much more exciting to discover that we are on a ball, half of us sticking upside down and spinning around in space. It is a mysterious force which holds us on. It’s going around a great big glob of gas that is fed by a fire that is completely different from any fire that we can make, but now we can make that fire – nuclear fire.

That is a much more exciting story to many people than the tales that other people used to make up about the universe – that we were living on the back of a turtle or something like that. They were wonderful stories, but the truth is so much more remarkable.

So what’s the pleasure in physics for me is that it is revealed that the truth is so remarkable, so amazing, and I have this disease – like many other people who have studied far enough to begin to understand a little of how things work.

They are fascinated by it, and this fascination drives them on to such an extent that they have been able to convince governments and so on to keep supporting them in this investigation.