
There is no fixed, eternal frame to the universe to define what may or may not exist.
Lee Smolin 
We show that some known classical results have particularly simple derivations within the Ashtekar formalism. These include Witten's positive energy theorem...
Lee Smolin

It is absurd in general relativity to speak of a universe in which nothing happens.
Lee Smolin 
From the beginning of physics, there have been those who imagined they would be the last generation to face the unknown. Physics has always seemed to its practitioners to be almost complete. This complacency is shattered only during revolutions, when honest people are forced to admit that they don't know the basics.
Lee Smolin 
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 
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.' â€¦interconnected, in that everything interacts with everything else.
Lee Smolin 
Neither space nor time has any existence outside the system of evolving relationships that comprises the universe. Physicists refer to this feature of general relativity as background independence.
Lee Smolin 
The first principle of cosmology must be 'There is nothing outside the universe'. This is not to exclude religion or mysticism... But if it is knowledge that we desire... we need to seek answers to questions about the things we can see... only things that exist in the universe.
Lee Smolin

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 
There is nothing beyond the world except what we see, no background to it except its particular history.
Lee Smolin 
There are unfortunately not a few good professional physicists who still think about the world as if space and time had an absolute meaning.
Lee Smolin 
The landscape problem and the problem of background independence are closely linked. The latter is the only route the former has to experimental confirmation.
Lee Smolin 
The relational picture of space and time has implications that are as radical as those of natural selection, not only for science but for our perspective on who we are and how we came to exist in this evolving universe of relations.
Lee Smolin 
Since the 1950s, the key equation of quantum gravity has been called the WheelerDeWitt equation. Bryce DeWitt and John Wheeler wrote it down, but in all the time since then, no one had been able to solve it. We found we could solve it exactly, and in fact we found an infinite number of exact solutions.
Lee Smolin

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 
Spacetime... turns out to be discrete, described by a structure called spin foam.
Lee Smolin 
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 
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 
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 
Time is described only in terms of change in the network of relationships that describes space.
Lee Smolin

I was joined by Carlo Rovelli, and we were able to make a fullfledged quantum theory of gravity... This became loop quantum gravity.
Lee Smolin 
One of the evident facts about the world is the stability of empty spacetime. 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 
We detect light and particles that have traveled billions of light years on their way across the universe to us. During the billions of years of travel, very small effects due to quantum gravity can be amplified to the point that we can detect them.
Lee Smolin 
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