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.


Three Roads to Quantum Gravity (2000)


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...

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...

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...

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...