Simplicity and beauty are the signs not of truth but of a well-constructed approximate model of a limited domain of phenomena.
Lee SmolinAny two particles in the universe attract each other through the gravitational interaction.
Lee SmolinJust like an ordinary guitar string, a fundamental string can vibrate in different modes. And it is these different modes of vibration of the string that are understood in string theory as being the different elementary particles.
Lee Smolin