Dreams of a Final Theory Quotes

“All logical arguments can be defeated by the simple refusal to reason logically”
― Steven Weinberg, Dreams of a Final Theory: The Search for The Fundamental Laws of Nature

“Once again I repeat: the aim pf physics at its most fundamental level is not just to describe the world but ti explain why it is the way it is.”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

“When you say anything controversial, you are likely to be blamed not so much for what you have said as for what people think that someone who has said what you said would also say.”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

“.....known as the anthropic principle, ehich states that the laws of nature should allow the existence of intelligent beings that can ask about the laws of nature.”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

“In its final form, the general theory of relativity was just a reinterpretation of the existing mathematics of curved spaces in terms of gravitation, together with a field equation that specified the curvature produced by any given amount of matter and energy. Remarkably, for the small densities and low velocities of the solar system, general relativity gave just the same results as Newton's theory of gravitation, with the two theories distinguished only by tiny effects like the precession of orbits and the deflection of light.”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

“The value today of philosophy to physics seems to me to be something like the value of early nation-states to their peoples. It is only a small exaggeration to say that, until the introduction of the post office, the chief service of nation-states was to protect their peoples from other nation-states. The insights of philosophers have occasionally benefited physicists, but generally in a negative fashion—by protecting them from the preconceptions of other philosophers.”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

“The theologian Paul Tillich once observed that among scientists only physicists seem capable of using the word "God" without embarrassment. Whatever one's religion or lack of it, it is an irresistible metaphor to speak of the final laws of nature in terms of the mind of God.”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

“energy of any sort generates gravitational fields and is in turn acted on by gravitational fields, so an energy filling all space could have important effects on the expansion of the universe.”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

“The idea of an anthropic principle began with the remark that the laws of nature seem surprisingly well suited to the existence of life. A famous example is provided by the synthesis of the elements. According to modern ideas, this synthesis began when the universe was about three minutes old (before then it was too hot for protons and neutrons to stick together in atomic nuclei) and was later continued in stars. It had originally been though that the elements were formed by adding one nuclear particle at a time to atomic nuclei, starting with the simplest element, hydrogen, whose nucleus consists of just one particle (a proton). But, although there was no trouble in building up helium nuclei, which contain four nuclear particles (two protons and two neutrons), there is no stable nucleus with five nuclear particles and hence no way to take the next step. The solution found eventually by Edwin Salpeter in 1952 is that two helium nuclei can come together in stars to form the unstable nucleus of the isotope beryllium 8, which occasionally before it has a chance to fission into two helium nuclei absorbs yet another helium nucleus and forms a nucleus of carbon. However, as emphasized in 1954 by Fred Hoyke, in order for this process to account for the observed cosmic abundance of carbon, there must be a state of the carbon nucleus that has an energy that gives it an anomalously large probability of being formed in the collison of a helium nucleus and a nucleus of beryllium 8. (Precisely such a state was subsequently found by experimenters working with Hoyle.) Once carbon is formed in stars, there is no obstacle to building up all the heavier elements, including those like oxygen and nitrogen that are necessary for known forms of life. But in order for this to work, the energy of this state of the carbon nucleus must be very close to the energy of a nucleus of beryllium 8 plus the energy of a helium nucleus. If the energy of this state of the carbon nucleus were too large or too small, then little carbon or heavier elements would be formed in stars, and with only hydrogen and helium there would be no way that life could arise. The energies of nuclear states depend in a complicated way on all the constants of physics, such as the masses and electric charges of the different types of elementary particles. It seems at first sight remarkable that these constants should take just the values that are needed to make it possible for carbon to be formed in this way.”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

“we think that all the forces of nature become united at something like the Planck energy, a million billion times larger than the highest energy reached in today's accelerators.”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

“At sufficiently high energy the force of gravitation between two typical elementary particles becomes as strong as any other force between them. The energy at which this happens is about a thousand million billion billion volts. This is known as the Planck energy.”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

“The apparent strengths of the forces in any field theory depend on two kinds of numerical parameter: the masses (if any) of the particles like W and Z particles that transmit the forces, and certain intrinsic strengths (also known as coupling constants) that characterize the likelihood for particles like photons or gluons or W and Z particles to be emitted and reabsorbed in particle reactions. The masses arise from spontaneous symmetry breaking, but the intrinsic strengths are numbers that appear in the underlying equation of the theory. Any symmetry that connects the strong with the weak and electromagnetic forces, even if spontaneously broken, would dictate that the intrinsic strengths of the electroweak and strong forces should (with suitable conventions for how they are defined) all be equal. The apparent differences between the strengths of the forces would have to be attributed to the spontaneous symmetry breaking that produces differences in the masses of the particles that transmit the forces, in much the same way that the differences between the electromagnetic and weak forces arise in the standard model from the fact that the electroweak symmetru breaking gives the W and Z particles very large masses, while the photon is left massless. But it is clear that the intrinsic strengths of the strong nuclear force and the electromagnetic force are not equal; the strong nuclear force, as its name suggests, is much stronger than the electromagnetic force, even though both of these forces are transmitted by massless particles, the gluons and photons.”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

“Plato and the neo-Platonists taught that the beauty we see in nature is a reflection of the beauty of the ultimate, the nous. For us, too, the beauty of present theories is an anticipation, a premonition, of the beauty of the final theory. And in any case, we would not accept any theory as final unless it were beautiful.”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

“The familiar Mercator projection used in maps of the earth gives a good idea of distances and directions near the equator, but produces horrible dostortions near the poles, with Greenland swelling to many times its actual size. In the same way, it is one sign of being in a gravitational field that there is no one freely falling frame of reference in which gravitational and inertial effects cancel everywhere.”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

“The fact that the force of gravity can be made to disappear for a brief time over a small region around any point in a gravitational field by adopting a suitable freely fallinf frame of reference is just like the property of curved surfaces, that we can make a map that despite the curvature of the surface correctly indicates distances and directions in the immediate neighborhood of any point we like. If the surface is curved, no one map will correctly indicate distances and directions everywhere; any map of a large region is a compromise, distorting distances and directions in one way or another.”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

“In general the fact that gravitational and inertial forces are both proportional to the mass of the body on which they act but depend on no other property of the body makes it possible at any point in any gravitational field to identify a "freely falling frame of reference" in which neither gravitational nor inertial forces are felt because they are in perfect balance for all bodies. When we do feel gravitational or inertial forces it is because we are not in a freely falling frame. For example, on the earth's surface freely falling bodies accelerate toward the center of the earth at 32 feet per second per second, and we feel a gravitational force unless we happen to be accelerating downward at the same rate. Einstein made a logical jump and guessed that gravitational and inertial forces were at bottom the same thing. He called this the principle of equivalence of gravitation and inertia, or the equivalence principle for short. According to this principle, any gravitational field is completely described by telling which frame of reference is freely falling at each point in space.”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

“We on earth do not feel either the gravitational field of the sun or the centrifugal force caused by the earth's motion around the sun because the two forces balance each other, but this balance would be spoiled if one force was proportional to the mass of the objects on which it acts and the other was not; some objects might then fall off the earth into the sun and others could be thrown off the earth into interstellar space.”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

“What one needs is a quantum mechanical model with a wave function that describes not only various systems under study but also something representing a conscious observer. With such a model, one would try to show that, as a result of repeated interactions of the observer with individual systems, the wave function of the combined system evolves with certainty to a final wave function, in which the observer has become convinced that the probabilities of the individual measurements are what are prescribed in the Copenhagen interpretation.”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

“What is surely impossible is that a theoretical physicist, given unlimited computing power, should deduce from the laws of physics that a certain complex structure is aware of its own existence.”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

“Using the standard model of elementary particles, we know how to follow the course of nuclear reactions in the standard "big bang" theory of the universe well enough to be able to calculate that the matter formed in the first few minutes of the universe was about three- quarters hydrogen and one-quarter helium, with only a trace of other elements, chiefly very light ones like lithium. This is the raw material out of which heavier elements were later formed in stars. Calculations of the subsequent course of nuclear reactions in stars show that the elements that are most abundantly produced are those whose nuclei are most tightly bound, and these elements include carbon, oxygen, and calcium. The stars dump this material into the interstellar medium in various ways, in stellar winds and supernova explosions, and it is out of this medium, rich in the constituents of chalk, that second-generation stars like the sun and their planets were formed. But this scenario still depends on a historical assumption-that there was a more-or-less homogenous big bang, with about ten billion photons for every quark. Efforts are being made to explain this assumption in various speculative cosmological theories, but these theories rest in turn on other historical assumptions.”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

“The principles of relativity and quantum mechanics are almost incompatible with each other and can coexist only in a limited class of theories. In the nonrelativistic quantum mechanics of the 1920s we could imagine almost any kind of force among electrons and nuclei, but as we shall see, this is not so in a relativistic theory: forces between particles can arise only from the exchange of other particles. Furthermore, all these particles are bundles of the energy, or quanta, of various sorts of fields. A field like an electric or magnetic field is a sort of stress in space, something like the various sorts of stress that are possible within a solid body, but a field is a stress in space itself. There is one type of field for each species of elementary particle; there is an electron field in the standard model, whose quanta are electrons; there is an electromagnetic field (consisting of electric and magnetic fields) , whose quanta are the photons; there is no field for atomic nuclei, or for particles (known as protons and neutrons) of which the nuclei are composed, but there are fields for various types of particles called quarks, out of which the proton and neutron are composed; and there are a few other fields I need not go into right now. The equations of a field theory like the standard model deal not with particles but with fields; the particles appear as manifestations of these fields. The reason that ordinary matter is composed of electrons, protons, and neutrons is simply that all the other massive particles are violently unstable. The standard model qualifies as an explanation because it is not merely what computer hackers call a kludge, an assortment of odds and ends thrown together in whatever way works. Rather, the structure of the standard model is largely fixed once one specifies the menu of fields that it should contain and the general principles (like the principles of relativity and quantum mechanics) that govern their interactions.”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

“The dream of a final theory inspires much of today’s work in high-energy physics, and though we do not know what the final laws might be or how many years will pass before they are discovered, already in today’s theories we think we are beginning to catch glimpses of the outlines of a final theory. The”
― Steven Weinberg, Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature