I want to talk mostly about science and not technology, except I have some things to say about technology as well.
I start from the proposition that this past century has been a marvelous century for science. Let me just remind you of the four landmark discoveries of this century.
In 1905, Albert Einstein in Switzerland put forward his theory of special relativity. That marked the end of classical physics.
In 1915, Einstein again put forward his theory of general relativity, as it was called, although more correctly its a theory of gravitation which entirely dismisses the basis on which Newton, three centuries earlier, had accounted for gravitation.
In the first quarter of this century, a huge army of very bright young men worked out the theory of quantum mechanics. Quantum mechanics is the theory of the very small things that are the size of atoms or smaller. And quantum mechanics actually makes it possible for people to design computer chips that do the jobs that all the machines on our desks now do.
But historically it marked a turning point in the evolution of fundamental science because it was, by 1926, the paradoxical basis for revising classical ideas of what it is that makes particles move in this way or that way.
And then the fourth landmark came in 1953 with the discovery by Watson and Crick, two young men in Cambridge, England, that the structure of DNA accounts both for the mechanism of inheritance in plants and animals and for the way in which each cell in each living thing all through its history gets its instruction from the DNA it carries in the centre of its cell.
So, DNA constituted a complete change in the way we regard the world we live in.
To summarize: Einsteins two theories have given us a sense that the universe in which we live, that this whole structure, is evolving as a whole, not simply that the individual parts of it, the Earth, the solar system, our galaxy and so on are evolving separately.
It all hangs together in a way that we dont properly understand as yet.
Quantum mechanics, as Ive said, is the theory of the very small.
Dirac, one of the people who contributed to that change in our view and, perhaps in a way the most perceptive of them all, wrote in the introduction of his great book, The Principle of Quantum Mechanics, published in 1929:
"And so the whole of physics and chemistry have been reduced to applied mathematics."
Quantum mechanics in his view and in that of many scientists now working has provided us with the tools with which to account for all the objects we see in the world around us, big or small.
I should mention that Dirac withdrew this boastful sentence in the second edition of his book, which came out in 1931. But that doesnt invalidate the principle. Hed simply come across some difficulties he hadnt anticipated.
And, of course, the DNA business has turned biology into, shall we say, chemistry of a particularly intricate and complex kind.
It doesnt mean in either case that chemistry has been outlawed by quantum mechanics, or that biology has been made redundant by the DNA conversion of biological difficulties into statements in chemistry.
Its simply that in practice the level of understanding has been deepened. And progress in science, I would say, consists always of that.
We keep on asking the same questions. How was the universe built? How does life go on? Where is the mind? [These are] all questions asked quite cogently by Aristotle more than two and a half thousand years ago.
But we keep asking the questions in a more demanding way and we keep demanding more precise and specific answers. Thats progress in fundamental science.
Ive said nothing about technology so far. But on the theme that this has been a marvelous century for science, let me just remind you that in the first five years we saw the foundation of two of the now major industries in the world.
In 1903, Marconi sent the first radio signals across the Atlantic and thereby founded the communication industry.
And the Wright brothers flew the measured mile in North Carolina and founded the aircraft industry that we have and value for the freedom it gives us to travel.
So, science has helped to make us healthier and wealthier than our grandparents could have expected for us. And it has also, I assert, made us wiser, because we understand the world better.
I must warn you of something. Ive described the past century as if it were a kind of revolution in science. Its not that at all.
Science is a collective enterprise and the remarkable thing about the past 500 years of modern science since the time of the earliest astronomer, Copernicus, the man who put the Sun and not the Earth at the centre of the universe is that its continuity is remarkable.
Ill give you two examples.
Galileo in the 16th century was the man who first pointed out that a force and an acceleration are virtually indistinguishable. Einstein used that same principle in building his theory of gravitation, calling the principle the equivalence principle.
So, 300 years went by until Galileos insight found its first expression in modern theory.
Then, in 1948, Richard Feynman from the California Institute of Technology, produced a theory of how it is that electrons interact with the electromagnetic field-- the electricity and magnetism in which theyre immersed so as to behave in particular ways.
Feynman used a theory of how waves and particles interact, which was a thought put forward first in 1832, more than a century earlier, by an Irishman called W.D. Hamilton.
"If Ive seen farther than other people, its because Ive stood on the shoulders of giants."
All the modern giants in science have stood on the shoulders of other giants and have been unable to do their work, been unable to have their insights, without the help of other, earlier people.
I have another caveat to make at this point.
[In] the past few years there have been a number of people saying:
"Well, okay, science has been so successful this century that surely now all the basic principles have been discovered. Its simply from here on in a matter of filling in the details, filling in the gaps do a kind of stamp- collecting job to make sure that we understand every single detail of the world we live in."
Some people go further than that and say:
"Look, its not simply that science has come to an end in the sense of the discovery of radically new principles. Its also the case that science creates so many problems that it would be of great value for the world as a whole if there could be a moratorium on research, shall we say for 10 years, or a century or two centuries, so that society can catch up, give itself a chance to come to terms with the social and ethical problems that modern science has created."
I think both those views are false.
I plan to show you some of the ways in which science needs to develop. It has certainly not come to an end. And the need to do that missing science quickly is urgent, because of the practical problems which Ill come to at the end of my talk.
My message is really quite simple.
After 500 years, science is much nearer its beginning than its end and there is no prospect that science will ever run out of things to do, of not merely an interesting kind, but an important kind.
How do we tell; how can one guess what science remains to be done?
You can do it and this is what I tried to do in the book Elizabeth Dickson so kindly referred to. Make a catalogue of our ignorance. What do we not know? What do we know that we dont know about the world at present?
Ill give you a check list.
One thing we need is a new theory, a really fundamental theory in science that will ascribe to space, the space around us, some microscopic structure that will help us to account for the particles of matter that the people who work at accelerator plants around the world have discovered; the quarks and the electrons that appear to be the fundamental constituents of matter.
The trouble is, at present, that the theory of how these particles exist is incomplete. There is a very esoteric theory, called string theory, by which people suppose that a particle is not a tiny speck of matter with no dimensions, but just a point in space where there happens to be matter.
That view, the current view, doesnt work. So people have thought that perhaps particles consist of very microscopic strings, loops of some material, matter which can vibrate and the vibrations produce the different kinds of particles the quarks and the electrons that are supposed now to be fundamental.
The string theory is very complicated and has a particular obstacle, an intellectual obstacle. It supposes that the strings exist in 10 dimensions. But some of these dimensions are curled up so tightly that they cannot be observed, even by the most powerful accelerators.
Its a fanciful concept, youll say. Many people take it seriously. It cannot be dismissed. It may be the way f5t also require: lots of courage and imagination.