Physicists From The United Kingdom

"Since building a universal virtual-reality generator is physically possible, it must actually be built in some universes."

"It is possible to build a virtual-reality generator whose repertoire includes every possible environment."

"Think of all our knowledge-generating processes, our whole culture and civilization, and all the thought processes in the minds of every individual, and indeed the entire evolving biosphere as well, as being a gigantic computation. The whole thing is executing a self-motivated, self-generating computer program. More specifically it is, as I have mentioned, a virtual-reality program in the process of rendering, with ever-increasing accuracy, the whole of existence."

"Thus we can see that if we take solipsism seriously - if we assume that it is true and that all valid explanations must scrupulously conform to it - it self destructs. How exactly does solipsism, taken seriously, differ from its common-sense rival, realism? The difference is based on no more than a renaming scheme. Solipsism insists on referring to objectively different things (such as external reality and my unconscious mind, or introspection and scientific observation) by the same names. But then it has to introduce the distinction through explanations in terms of something like the 'outer part of myself'. But no such extra explanation would be necessary without its insistence on an inexplicable renaming scheme. Solipsism must also postulate the existence of an additional class of processes - invisible, inexplicable processes which give the mind the illusion of living in an external reality. The solipsist, who believes that nothing exists other than the contents of one mind, must also believe that that mind is a phenomenon of greater multiplicity than is normal supposed. It contains other-people-like thoughts, planet-like thoughts and laws-of-physics-like thoughts. These thoughts are real. They develop in a complex way (or pretend to), and they have enough autonomy to surprise, disappoint, enlighten or thwart other classes of thoughts which call themselves 'I'. Thus the solipsist's explanation of the world is in terms of interacting thoughts rather than interacting objects. But those thoughts are real, and interact according to the same rules that the realist says govern the interaction of objects. Thus solipsism, far from being a world view striped to its essentials, is actually just realism disguised and weighed down by additional baggage, introduced only to be explained away."

"Reality contains not only evidence, but also the means (such as our minds, and our artefacts) of understanding it. There are mathematical symbols in physical reality. The fact that it is we who put them there does not make them any less physical."

"The quantum theory of parallel universes is not the problem, it is the solution. It is not some troublesome, optional interpretation emerging from arcane theoretical considerations. It is the explanation—the only one that is tenable—of a remarkable and counter-intuitive reality."

"To say that prediction is the purpose of a scientific theory is to confuse means with ends. It is like saying that the purpose of a spaceship is to burn fuel. … Passing experimental tests is only one of many things a theory has to do to achieve the real purpose of science, which is to explain the world."

"A prediction, or any assertion, that cannot be defended might still be true, but an explanation that cannot be defended is not an explanation."

"The overwhelming majority of theories are rejected because they contain bad explanations, not because they fail experimental tests."

"I must confess it was very unexpected and I am very startled at my metamorphosis into a chemist."

"I came into the room which was half-dark and presently spotted Lord Kelvin in the audience, and realised that I was in for trouble at the last part of my speech dealing with the age of the Earth, where my views conflicted with his. To my relief, Kelvin fell fast asleep, but as I came to the important point, I saw the old bird sit up, open an eye and cock a baleful glance at me. Then a sudden inspiration came, and I said Lord Kelvin had limited the age of the Earth, provided no new source [of heat] was discovered. That prophetic utterance referred to what we are now considering tonight, radium! Behold! The old boy beamed upon me."

"When we have found how the nucleus of atoms is built up we shall have found the greatest secret of all — except life. We shall have found the basis of everything — of the earth we walk on, of the air we breathe, of the sunshine, of our physical body itself, of everything in the world, however great or however small — except life."

"Radioactivity is shown to be accompanied by chemical changes in which new types of matter are being continually produced. … The conclusion is drawn that these chemical changes must be sub-atomic in character."

"I know what the atom looks like!"

"An alleged scientific discovery has no merit unless it can be explained to a barmaid."

"Don't let me catch anyone talking about the Universe in my department."

"That which is not measurable is not science. — also attributed to Lord Kelvin"

"All science is either physics or stamp collecting."

"It is not in the nature of things for any one man to make a sudden violent discovery; science goes step by step, and every man depends on the work of his predecessors. When you hear of a sudden unexpected discovery—a bolt from the blue, as it were—you can always be sure that it has grown up by the influence of one man on another, and it is this mutual influence which makes the enormous possibility of scientific advance. Scientists are not dependent on the ideas of a single man, but on the combined wisdom of thousands of men, all thinking of the same problem, and each doing his little bit to add to the great structure of knowledge which is gradually being erected."

"It was almost as incredible as if you fired a 15-inch shell at a piece of tissue paper and it came back and hit you."

"We may in these processes obtain very great quantities of energy, but on the average we cannot hope to obtain energy for practical use in this way. The bombardment of the atom is a very poor and inefficient way of producing energy and anyone who is looking for a source of cheap power in the transformation of the atom, is talking pure moonshine... Some day the knowledge we may gain may be of practical value, but there is no indication of it yet."

"It is just as surprising as if a gunner fired a shell at a single sheet of paper and for some reason or other the projectile bounded back again."

"He seemed bored with his radio work. ...he had transmitted signals more than half a mile through Cambridge's stone builidings, and there was great interest in finding a way to use such signals in ship-to-shore communications... Some scientists, astonished at those demonstrations, believed that Rutherford's work in New Zealand and then at the Cavendish was actually ahead of the work being done by Guglielmo Marconi..."

"One can hardly speak of being friendly with a force of nature."

"Rutherford did not pretend to understand quantum mechanics, but he understood that the Gamow formula would give his accelerator a crucial advantage. Even particles accelerated at much lower energies... would be able to penetrate into nuclei. Rutherford invited Gamow to Cambridge in January 1929... [They] became firm friends and Gamow's insight gave Rutherford the impetus to go full steam ahead with the building of his accelerator."

"He died a year before the discovery of the fission of the uranium nucleus in Berlin in 1938, the discovery which turned nuclear physics into a big industry and a weapon of war."

"The switch from natural sources of particles to accelerators would start a new era in the history of science, the era of accelerator physics. ...The two men who actually built the first accelerator were John Cockcroft and Ernest Walton, graduate students working... under the supervision of Rutherford. ...For five years they struggled to create a technology of big machines in a laboratory of tabletop experiments, just as the Wright brothers had struggled to create a technology of flying machines in a bicycle shop ....In April of 1932, they had a machine that produced a steady stream of hydrogen nuclei with an energy of about half a million volts. ...Walton was... ready to do the experiment... to bombard a target made of the light metal lithium. The result was spectacular. The lithium nuclei were split in two and fell apart into pairs of helium nuclei. The helium nuclei came out with thirty times as much energy as the hydrogen nuclei going in. ...Rutherford happily spent the rest of the day serving as Walton's assistant... That day, the era of tabletop nuclear physics ended and the era of big machines and big projects began."

"Rutherford's discovery was the beginning of the science that came to be called nuclear physics. ...The projectiles that he used to explore the nucleus were particles produced in the disintegration of radium... discovered by Marie Curie in 1898. The particles are helium nuclei that are emitted at high speed when radium atoms decay...The twenty years between 1909 and 1929 were the era of tabletop nuclear physics. ...Small and simple experiments were sufficient to establish the basic laws of nuclear physics."

"In 2005, we had a couple of things going for us. First, of course, we knew how the experiment was supposed to come out. They had been out there in the blue. We also had faster, stronger, and more reliable equipment to pull vacuums, greatly reducing the results contaminated by the odd air molecule or hydrogen atom. But we, and the world, now know the deadly dangers of radioactivity. Rutherford used to toss bits of radioactive material in his pocket and then, before dinner, into the top drawer of his desk at home. ...If we tried to use what they used, we couldn't all be in this room... We couldn't be in the building."

"Rutherford's attitude to his own discoveries is illustrated by his response to a remark of one who was present at the moment of one of his great discoveries: "Rutherford, you are always on the crest of the wave." To which Rutherford responded: "I made the wave, didn't I?" Somehow from Rutherford's vantage point everything he said seems right, even including his remark, "I do not let my boys waste their time" when he was asked if he encouraged his students to study relativity! Rutherford was a happy warrior if ever there was one."

"The first point that arises is the atom. I was brought up to look at the atom as a nice hard fellow, red or grey in colour, according to taste. In order to explain the facts, however, the atom cannot be regarded as a sphere of material, but rather as a sort of wave motion of a peculiar kind. The theory of wave-mechanics, however bizarre it may appear... has the astonishing virtue that it works, and works in detail, so that it is now possible to understand and explain things which looked almost impossible in earlier days. One of the problems encountered is the relation between the electron, an atom and the radiation produced by them jointly; the new mechanics states the type of radiation emitted with correct numerical relations. When applied to the periodic table, a competent and laborious mathematician can predict the periodic law from first principles."

"I have broken the machine and touched the ghost of matter."

"If your experiment needs statistics, you ought to have done a better experiment."

"...Rutherford never spent more than £2500 a year on his research programme. He resisted suggestions that an industrial appeal might provide him with more money and he did not believe in the economic significance of any of the work he was doing. He used to boast that ‘we have no money, so we shall have to think’."

"We've got no money, so we've got to think."

"We're like children who always want to take apart watches to see how they work."