Lee Smolin: Theory

“Combine general relativity and quantum theory into a single theory that can claim to be the complete theory of nature. This is called the problem of quantum gravity.”

Lee Smolin

The Trouble With Physics: The Rise of String Theory, The Fall of a Science, and What Comes Next (2007)

Nature , Problem

“The positive energy theorem was for half a century or more an open challenge to relativists. Many attempts were made to prove flat spacetime was stable, but none completely succeeded completely until a majestic tour de force of geometric reasoning of Shoen and Yau. This was followed two years later by a proof of Witten, which was as elegant as it was short. It is this proof of Witten’s that we take as a template here for the quantum theory.”

Lee Smolin

"Positive energy in quantum gravity" arXiv (Jun 10, 2014)

“Quantum theory can be described as a new kind of language to be used in a dialogue between us and the systems we study with our instruments. …It tells us nothing about what the world would be like in our absence.”

Lee Smolin

The Trouble With Physics: The Rise of String Theory, The Fall of a Science, and What Comes Next (2007)

World , Study

“Some of the effects predicted by the theory [of loop quantum gravity] appear to be in conflict with one of the principles of Einstein's special theory of relativity… that the speed of light is a universal constant. …Photons of higher energy travel slightly slower than low-energy photons. …the principle of [general] relativity is preserved but Einstein's special theory of relativity requires modification. …A photon can have an energy-dependent speed without violating the principle of [general] relativity!”

Lee Smolin

"Loop Quantum Gravity," The New Humanists: Science at the Edge (2003)

Travel , Light , Universe , Appearance

“Many of the founders of quantum mechanics, including Einstein, Erwin Schrödinger, and Louis de Broglie… were realists. For them quantum theory… was not a complete theory, because it did not provide a picture of reality absent our interaction with it. On the other side were Niels Bohr, Werner Heisenberg, and many others. Rather than being appalled, they embraced this new way of doing science.”

Lee Smolin

The Trouble With Physics: The Rise of String Theory, The Fall of a Science, and What Comes Next (2007)

Way , Reality , Science

“Relativity and… quantum… remain incomplete…. the main reason each is incomplete is the existence of the other. The mind calls for a third theory to unify all of physics, and for a simple reason. Nature is… "unified." …interconnected, in that everything interacts with everything else.”

Lee Smolin

The Trouble With Physics: The Rise of String Theory, The Fall of a Science, and What Comes Next (2007)

Nature

“We have known since the middle of the nineteenth century that the world is not composed only of particles. …the world is also composed of fields. …General relativity is a theory of… the gravitational field. …Because there are three sets of field lines, the gravitational field defines a network of relationships having to do with how the… lines link with one another. …This is why we call relativity a relational theory.”

Lee Smolin book Three Roads to Quantum Gravity

Three Roads to Quantum Gravity (2000)

World

“One of the evident facts about the world is the stability of empty space-time. In classical general relativity we can explain this as a consequence of the positive energy theorem… the positive energy theorem must extend in some suitable form to any viable quantum theory of gravity.”

Lee Smolin

"Positive energy in quantum gravity" arXiv (Jun 10, 2014)

World , Time

“I was joined by Carlo Rovelli, and we were able to make a full-fledged quantum theory of gravity… This became loop quantum gravity.”

Lee Smolin

"Loop Quantum Gravity," The New Humanists: Science at the Edge (2003)

“Many of us believed in the possibility of a principled explanation for the laws of nature. We hoped to discover a short list of principles, which could be realized in a unique theory, which would retrodict the standard model and uniquely predict the physics to be discovered beyond it. The shocking implication of the results of Strominger reported in 1986 was that it was not to be, at least within the confines of string theory. …String theory offered more, however… It offered the promise of a setting in which the different perturbative string theories are realized as expansions around solutions of a still more fundamental theory. …That more fundamental theory would have to be background independent…”

Lee Smolin

"A perspective on the landscape problem" arXiv (Feb 15, 2012)

Law , Hope , Nature

“There is a smallest unit of space. Its minimum value is given by the cube of the Planck length… If you take a volume of space and measure it to a very fine precision… It has to fall into some discrete series of numbers, just like the energy of an electron in an atom. …we can calculate the discrete areas and volumes from the theory.”

Lee Smolin

"Loop Quantum Gravity," The New Humanists: Science at the Edge (2003)

“In both quantum theory and general relativity, we encounter predictions of physically sensible quantities becoming infinite. This is likely the way that nature punishes impudent theorists who dare to break her unity. …If infinities are signs of missing unification, a unified theory will have none. It will be what we call a finite theory.”

Lee Smolin

The Trouble With Physics: The Rise of String Theory, The Fall of a Science, and What Comes Next (2007)

Way , Nature

“In quantum theory, distance is inverse to energy, because you need particles of very high energy to probe very short distances. The inverse of the Planck energy is the Planck length.”

Lee Smolin

"Loop Quantum Gravity," The New Humanists: Science at the Edge (2003)

“In string theory one studies strings moving in a fixed classical spacetime. …what we call a background-dependent approach. …One of the fundamental discoveries of Einstein is that there is no fixed background. The very geometry of space and time is a dynamical system that evolves in time. The experimental observations that energy leaks from binary pulsars in the form of gravitational waves—at the rate predicted by general relativity to the… accuracy of eleven decimal places—tell us that there is no more a fixed background of spacetime geometry than there are fixed crystal spheres holding the planets up.”

Lee Smolin

"Loop Quantum Gravity," The New Humanists: Science at the Edge (2003)

Study , Time , Dependency

“I believe that the main lesson of relativity and quantum theory is that the world is nothing but an evolving network of relationships.”

Lee Smolin book Three Roads to Quantum Gravity

Three Roads to Quantum Gravity (2000)

World

“Since the 1960s, particle theory had been split into two groups: those following the atomism of the quark theory and those who had followed the anti-atomism of that had led from the bootstrap program to the string theory. What happened in 1984 was that it was realised that string theory could combine and satisfy the aspirations of both approaches to fundamental physics. Thus, the community of gauge theorists, driven by the failure of the proton decay experiments to search for new ideas that could unify physics, all of a sudden encountered their old friends, the string theorists, in the middle of what might be called a desert of disappointed expectations.”

Lee Smolin book The Life of the Cosmos

The Life of the Cosmos (1997)

Disappointment , Search , Communication , Idea

“In the theory of electric fields it is assumed that points have meaning. …Physicists using general relativity… cannot speak of a point, except by naming some features of the field lines that will uniquely distinguish that point. …the network of relationships evolve with time… constantly changing.”

Lee Smolin book Three Roads to Quantum Gravity

Three Roads to Quantum Gravity (2000)

Change , Time

“Unfortunately, so far… a truly background independent formulation of string theory has not been achieved… [It is] often called the search for M theory…”

Lee Smolin

"A perspective on the landscape problem" arXiv (Feb 15, 2012)

Search

“String theory seems to be incompatible with a world in which a cosmological constant has a positive sign, which is what the observations indicate.”

Lee Smolin

"Loop Quantum Gravity," The New Humanists: Science at the Edge (2003)

World

“While most people… were seeking to modify the principles of either relativity or quantum theory, we surprised ourselves (and many other people) by succeeding in putting them together without modifying their principles.”

Lee Smolin

"Loop Quantum Gravity," The New Humanists: Science at the Edge (2003)

People