Quotes by Theoretical Physicists

Science is built of facts the way a house is built of bricks but an accumulation of facts is no more science than a pile of bricks is a house.
Henri Poincaré
In Einstein's equation, time is a river. It speeds up, meanders, and slows down. The new wrinkle is it can have whirlpools and fork into two rivers. So, if the river of time can be bent into a pretzel, create whirlpools and fork into two rivers, then time travel cannot be ruled out.
Michio Kaku
Thinking must never submit itself, neither to a dogma, nor to a party, nor to a passion, nor to an interest, nor to a preconceived idea, nor to whatever it may be, if not to facts themselves, because, for it, to submit would be to cease to be.
Jules Henri Poincaré
Mathematics has the inhuman quality of starlight, brilliant and sharp, but cold.
Hermann Weyl
Mathematics is the art of giving the same name to different things.
Henri Poincaré
A physicist, an engineer and a psychologist are called in as consultants to a dairy farm whose production has been below par. Each is given time to inspect the details of the operation before making a report.The first to be called is the engineer, who states: "The size of the stalls for the cattle should be decreased. Efficiency could be improved if the cows were more closely packed, with a net allotment of 275 cubic feet per cow. Also, the diameter of the milking tubes should be increased by 4 percent to allow for a greater average flow rate during the milking periods."The next to report is the psychologist, who proposes:"The inside of the barn should be painted green. This is a more mellow color than brown and should help induce greater milk flow. Also, more trees should be planted in the fields to add diversity to the scenery for the cattle during grazing, to reduce boredom."Finally, the physicist is called upon. He asks for a blackboard and then draws a circle. He begins: "Assume the cow is a sphere....
Lawrence M. Krauss
In some sense, gravity does not exist; what moves the planets and the stars is the distortion of space and time.
Michio Kaku
After that cancellation [of the Superconducting Super Collider in Texas, after $2 billion had been spent on it], we physicists learned that we have to sing for our supper. ... The Cold War is over. You can't simply say “Russia!” to Congress, and they whip out their checkbook and say, “How much?” We have to tell the people why this atom-smasher is going to benefit their lives.
Michio Kaku
There was a sense that the one true theory had been discovered. Nothing else was important or worth thinking about. Seminars devoted to string theory sprang up at many of the major universities and research institutes. At Harvard, the string theory seminar was called the Postmodern Physics seminar. This appellation was not meant ironically.
Lee Smolin
Physicists believe that the Gaussian law has been proved in mathematics while mathematicians think that it was experimentally established in physics.
Henri Poincaré
Some string theorists prefer to believe that string theory is too arcane to be understood by human beings, rather than consider the possibility that it might just be wrong.
Lee Smolin
Why is it that showers and even storms seem to come by chance, so that many people think it quite natural to pray for rain or fine weather, though they would consider it ridiculous to ask for an eclipse by prayer?
Henri Poincaré
I've told you two things : First, you're much more insignificant than you ever imagined and second, the future is miserable. But you should be happy, because we may live in a universe without purpose but that means the purpose in our lives is the purpose we create. And we should consider ourselves fortunate to have evolved in this place in the middle of nowhere and evolved a consciousness so we can understand the universe from the earliest moments of the big bang to the far future. So instead of being depressed, you should enjoy your brief moment in the sun.
Lawrence M. Krauss
The real bottleneck is software. Creating software can be done only the old-fashioned way. A human -sitting quietly in a chair with a pencil, paper and laptop- is going to have to write the codes... One can mass-produce hardware and increase it's power by piling on more and more chips, but you cannot mass-produce the brain.
Michio Kaku
These computer simulations try only to duplicate the interactions between the cortex and the thalamus. Huge chunks of the brain are therefore missing. Dr. [Dharmendra] Modha understands the enormity of his project. His ambitious research has allowed him to estimate what it would take to create a working model of the entire human brain, and not just a portion or a pale version of it, complete with all parts of the neocortex and connections to the senses. He envisions using not just a single Blue Gene computer [with over a hundred thousand processors and terabytes of RAM] but thousands of them, which would fill up not just a room but an entire city block. The energy consumption would be so great that you would need a thousand-megawatt nuclear power plant to generate all the electricity. And then, to cool off this monstrous computer so it wouldn't melt, you would need to divert a river and send it through the computer circuits.It is remarkable that a gigantic, city-size computer is required to simulate a piece of human tissue that weighs three pounds, fits inside your skull, raises your body temperature by only a few degrees, uses twenty watts of power, and needs only a few hamburgers to keep it going.
Michio Kaku
Nature creates curved lines while humans create straight lines.
Hideki Yukawa
Science and technology are the engines of prosperity. Of course, one is free to ignore science and technology, but only at your peril. The world does not stand still because you are reading a religious text. If you do not master the latest in science and technology, then your competitors will.
Michio Kaku
Consider now the Milky Way. Here also we see an innumerable dust, only the grains of this dust are no longer atoms but stars; these grains also move with great velocities, they act at a distance one upon another, but this action is so slight at great distances that their trajectories are rectilineal; nevertheless, from time to time, two of them may come near enough together to be deviated from their course, like a comet that passed too close to Jupiter. In a word, in the eyes of a giant, to whom our Suns were what our atoms are to us, the Milky Way would only look like a bubble of gas.
Henri Poincaré
Our Sun is not Earth’s true “mother.” Although many peoples of Earth have worshipped the Sun as a god that gave birth to Earth, this is only partially correct. Although Earth was originally created from the Sun (as part of the ecliptic plane of debris and dust that circulated around the Sun 4.5 billion years ago), our Sun is barely hot enough to fuse hydrogen to helium.This means that our true “mother” sun was actually an unnamed star or collection of stars that died billions of years ago in a supernova, which then seeded nearby nebulae with the higher elements beyond iron that make up our body. Literally, our bodies are made of stardust, from stars that died billions of years ago.
Michio Kaku
The philosophers make still another objection: "What you gain in rigour," they say, "you lose in objectivity. You can rise toward your logical ideal only by cutting the bonds which attach you to reality. Your science is infallible, but it can only remain so by imprisoning itself in an ivory tower and renouncing all relation with the external world. From this seclusion it must go out when it would attempt the slightest application.
Henri Poincaré
Pure analysis puts at our disposal a multitude of procedures whose infallibility it guarantees; it opens to us a thousand different ways on which we can embark in all confidence; we are assured of meeting there no obstacles; but of all these ways, which will lead us most promptly to our goal? Who shall tell us which to choose? We need a faculty which makes us see the end from afar, and intuition is this faculty. It is necessary to the explorer for choosing his route; it is not less so to the one following his trail who wants to know why he chose it.
Henri Poincaré
The saddest thing about these imagined deathbed conversions is that, even if they were real, they could hardly be seen as victories for Christ. They are stories in which the final pain of a fatal disease, or the fear of imminent death and eternal punishment, is identified as the factor necessary for otherwise rational people to believe in the supernatural.If mental torture is required to effect a conversion, what does that say about the reliability of the fundamental premises of Christianity to begin with? Evangelicals would be better advised to concentrate on converting the living. Converting the deceased suggests only that they can't convince those who can argue back. They should let the dead rest in peace.
Lawrence M. Krauss
A universe without purpose should neither depress us nor suggest that our lives are purposeless. Through an awe-inspiring cosmic history we find ourselves on this remote planet in a remote corner of the universe, endowed with intelligence and self-awareness. We should not despair, but should humbly rejoice in making the most of these gifts, and celebrate our brief moment in the sun.
Lawrence M. Krauss
From the age of 13, I was attracted to physics and mathematics. My interest in these subjects derived mostly from popular science books that I read avidly. Early on I was fascinated by theoretical physics and determined to become a theoretical physicist. I had no real idea what that meant, but it seemed incredibly exciting to spend one's life attempting to find the secrets of the universe by using one's mind.
David Gross
If the universe doesn't care about us and if we're an accident in a remote corner of the universe, in some sense it makes us more precious. The meaning in our lives is provided by us; we provide our own meaning.
Lawrence M. Krauss
The universe is a symphony of strings. And the "Mind of God," which Einstein wrote eloquently about, is cosmic music resonating throughout hyperspace.
Michio Kaku
Inflation is continuous and eternal, with big bangs happening all the time, with universes sprouting from other universes. In this picture, universes can “bud” off into other universes, creating a “multiverse.” In this theory, spontaneous breaking may occur anywhere within our universe, allowing an entire universe to bud off our universe. It also means that our own universe might have budded from a previous universe. In the chaotic inflationary model, the multiverse is eternal, even if individual universes are not. Some universes may have a very large Omega, in which case they immediately vanish into a big crunch after their big bang. Some universes only have a tiny Omega and expand forever. Eventually, the multiverse becomes dominated by those universes that inflate by a huge amount.In retrospect, the idea of parallel universes is forced upon us.
Michio Kaku
In science fiction, telepaths often communicate across language barriers, since thoughts are considered to be universal. However, this might not be true. Emotions and feelings may well be nonverbal and universal, so that one could telepathically send them to anyone, but rational thinking is so closely tied to language that it is very unlikely that complex thoughts could be sent across language barriers. Words will still be sent telepathically in their original language.
Michio Kaku
We need to live our experience as it is and with our eyes open. The universe is the way it is, whether we like it or not.
Lawrence M. Krauss
How is it that there are so many minds that are incapable of understanding mathematics? ... the skeleton of our understanding, ... and actually they are the majority. ... We have here a problem that is not easy of solution, but yet must engage the attention of all who wish to devote themselves to education.
Henri Poincaré
Something as superfluous as "play" is also an essential feature of our consciousness. If you ask children why they like to play, they will say, "Because it's fun." But that invites the next question: What is fun? Actually, when children play, they are often trying to reenact complex human interactions in simplified form. Human society is extremely sophisticated, much too involved for the developing brains of young children, so children run simplified simulations of adult society, playing games such as doctor, cops and robber, and school. Each game is a model that allows children to experiment with a small segment of adult behavior and then run simulations into the future. (Similarly, when adults engage in play, such as a game of poker, the brain constantly creates a model of what cards the various players possess, and then projects that model into the future, using previous data about people's personality, ability to bluff, etc. The key to games like chess, cards, and gambling is the ability to simulate the future. Animals, which live largely in the present, are not as good at games as humans are, especially if they involve planning. Infant mammals do engage in a form of play, but this is more for exercise, testing one another, practicing future battles, and establishing the coming social pecking order rather than simulating the future.)
Michio Kaku
More often than you might think, teaching science is inseparable from teaching doubt.
Lawrence M. Krauss
The one thing that I want every single child to have experienced at some point in their life, as part of their education, is to have some idea they hold to be true, and at the very basis of their being, proved to be wrong.Because that opens your mind to the realization that the world is different than you thought it would be, and you have to begin to open your mind to the possibilities of existence.And opening your mind frees you, it doesn't constrain you. It makes the world more wonderful, more exciting, and more worth living in.
Lawrence M. Krauss
It would take a civilization far more advanced than ours, unbelievably advanced, to begin to manipulate negative energy to create gateways to the past. But if you could obtain large quantities of negative energy—and that's a big “IF”—then you could create a time machine that apparently obeys Einstein's equation and perhaps the laws of quantum theory.
Michio Kaku
If we wish to foresee the future of mathematics, our proper course is to study the history and present condition of the science.
Henri Poincaré
Reality is complicated. There is no justification for all of the hasty conclusions.
Hideki Yukawa
It from bit. It’s an unorthodox theory, which starts with the assumption that information is at the root of all existence. When we look at the moon, a galaxy, or an atom, their essence, he claims, is in the information stored within them. But this information sprang into existence when the universe observed itself. He draws a circular diagram, representing the history of the universe. At the beginning of the universe, it sprang into being because it was observed. This means that “it” (matter in the universe) sprang into existence when information (“bit”) of the universe was observed. He calls this the “participatory universe”—the idea that the universe adapts to us in the same way that we adapt to the universe, that our very presence makes the universe possible.
Michio Kaku
To resolve the discrepancy between waves of probability and our commonsense notion of existence, Bohr and Heisenberg assumed that after a measurement is made by an outside observer, the wave function magically “collapses,” and the electron falls into a definitestate—that is, after looking at the tree, we see that it is truly standing. In other words, the process of observation determines the final state of the electron. Observation is vital to existence.
Michio Kaku
Before an observation is made, an object exists in all possible states simultaneously. To determine which state the object is in, we have to make an observation, which “collapses” the wave function, and the object goes into a definite state. The act of observation destroys the wave function, and the object now assumesa definite reality.
Michio Kaku
But if I make an observation, what is to determine which state I am in? This means that someone else has to observe me to collapse my wave function.
Michio Kaku
The Greeks made Space the subject-matter of a science of supreme simplicity and certainty. Out of it grew, in the mind of classical antiquity, the idea of pure science. Geometry became one of the most powerful expressions of that sovereignty of the intellect that inspired the thought of those times. At a later epoch, when the intellectual despotism of the Church, which had been maintained through the Middle Ages, had crumbled, and a wave of scepticism threatened to sweep away all that had seemed most fixed, those who believed in Truth clung to Geometry as to a rock, and it was the highest ideal of every scientist to carry on his science 'more geometrico.
Hermann Weyl
Maybe somewhere telepaths walked the Earth, but I wasn't one of them. In the process, I began to realize that the wondrous exploits of telepaths were probably impossible--at least without outside assistance. But in the years that followed, I also slowly learned another lesson: to fathom the greatest secrets in the universe, one did not need telepathic or superhuman abilities. One just had to have an open, determined, and curious mind. In particular, in order to understand whether the fantastic devices of science fiction are possible, you have to immerse yourself in advanced physics. To understand the precise point when the possible becomes the impossible, you have to appreciate and understand the laws of physics.
Michio Kaku
We should try to leave the world a better place than when we entered it. As individuals, we can make a difference, whether it is to probe the secrets of Nature, to clean up the environment and work for peace and social justice, or to nurture the inquisitive, vibrant spirit of the young by being a mentor and a guide.
Michio Kaku
I have concluded that we are in a world made by rules created by an intelligence. Believe me, everything that we call chance today won’t make sense anymore. To me it is clear that we exist in a plan which is governed by rules that were created, shaped by a universal intelligence and not by chance.
Michio Kaku
With mathematics we stand precisely at that intersection of bondage and freedom that is the essence of the human itself.
Hermann Weyl
[I]n science we have to be particularly cautious about 'why' questions. When we ask, 'Why?' we usually mean 'How?' If we can answer the latter, that generally suffices for our purposes. For example, we might ask: 'Why is the Earth 93 million miles from the Sun?' but what we really probably mean is, 'How is the Earth 93 million miles from the Sun?' That is, we are interested in what physical processes led to the Earth ending up in its present position. 'Why' implicitly suggests purpose, and when we try to understand the solar system in scientific terms, we do not generally ascribe purpose to it.
Lawrence M. Krauss
The handsome and the beautiful may earn the admiration of society, but all the wondrous inventions of the future are a by-product of the unsung, anonymous scientists.
Michio Kaku
It's hard to imagine a more extraordinary claim than that some hidden intelligence created a universe of more than a hundred billion galaxies, each containing more than a hundred billion stars, and then waited more than 13.7 billion years until a planet in a remote corner of a single galaxy evolved an atmosphere sufficiently oxygenated to support life, only to then reveal his existence to an assortment of violent tribal groups before disappearing again.
Lawrence M. Krauss
My work has always tried to unite the True with the Beautiful and when I had to choose one or the other, I usually chose the Beautiful.
Hermann Weyl
(The string is extremely tiny, at the Planck length of 10 ^-33 cm, a billion billion times smaller than a proton, so all subatomic particles appear pointlike.)If we were to pluck this string, the vibration would change; the electron might turn into a neutrino. Pluck it again and it might turn into a quark. In fact, if you plucked it hard enough, it could turn into any of the known subatomic particles.Strings can interact by splitting and rejoining, thus creating the interactions we see among electrons and protons in atoms. In this way, through string theory, we can reproduce all the laws of atomic and nuclear physics. The "melodies" that can be written on strings correspond to the laws of chemistry. The universe can now be viewed as a vast symphony of strings.
Michio Kaku
For most people, the central questions of existence ultimately come down to transcendental ones: Why is there a universe at all? Why are we here?Whatever presumptions one might bring to the question "Why?," if we understand the "how" better, "why" will come into sharper focus.
Lawrence M. Krauss
The universe has a much greater imagination than we do, which is why the real story of the universe is far more interesting than any of the fairy tales we have invented to describe it.
Lawrence M. Krauss
Now, almost one hundred years later, it is difficult to fully appreciate how much our picture of the universe has changed in the span of a single human lifetime. As far as the scientific community in 1917 was concerned, the universe was static and eternal, and consisted of a one single galaxy, our Milky Way, surrounded by vast, infinite, dark, and empty space. This is, after all, what you would guess by looking up at the night sky with your eyes, or with a small telescope, and at the time there was little reason to suspect otherwise.
Lawrence M. Krauss
Metaphysical speculation is independent of the physical validity of the Big Bang itself and is irrelevant to our understanding of it.
Lawrence M. Krauss
[On the practical applications of particle physics research with the Large Hadron Collider.]Sometimes the public says, 'What's in it for Numero Uno? Am I going to get better television reception? Am I going to get better Internet reception?' Well, in some sense, yeah. ... All the wonders of quantum physics were learned basically from looking at atom-smasher technology. ... But let me let you in on a secret: We physicists are not driven to do this because of better color television. ... That's a spin-off. We do this because we want to understand our role and our place in the universe.
Michio Kaku
‎By 2100, our destiny is to become like the gods we once worshipped and feared. But our tools will not be magic wands and potions but the science of computers, nanotechnology, artificial intelligence, biotechnology, and most of all, the quantum theory.
Michio Kaku
One possibility is: God is nothing but the power of the universe to organize itself.
Lee Smolin
In 5 billion years, the expansion of the universe will have progressed to the point where all other galaxies will have receded beyond detection. Indeed, they will be receding faster than the speed of light, so detection will be impossible. Future civilizations will discover science and all its laws, and never know about other galaxies or the cosmic background radiation. They will inevitably come to the wrong conclusion about the universe......We live in a special time, the only time, where we can observationally verify that we live in a special time.
Lawrence M. Krauss
It is often stated that of all the theories proposed in this century, the silliest is quantum theory. In fact, some say that the only thing that quantum theory has going for it is that it is unquestionably correct.
Michio Kaku
The handsome and the beautiful may earn the admiration of society, but all the wondrous inventions of the future are a by-product of the unsung, anonymous scientists.
Michio Kaku