Helgoland

by Carlo Rovelli

The mind does not enter into the equation. Special ‘observers’ have no real role to play in the theory. The central point is simpler: we cannot separate the properties of the objects from the objects interacting with them in order for these properties to be manifested in the first place. All of the (variable) properties of an object, in the final analysis, are such and exist only with respect to other objects. ‘Contextuality’ is the technical name that denotes this central aspect of quantum physics: things exist in a context. An isolated object, taken in itself, independent of every interaction, has no particular state. At most we can attribute to it a kind of probabilistic disposition107 to manifest itself in one way or another. But even this is only an anticipation of future phenomena, a reflection of phenomena past, and only and always relative to another object. The conclusion is revolutionary. It leaps beyond the idea that the world is made up of a substance that has attributes and forces us to think about everything in terms of relations.108 This, I believe, is what we have discovered about the world with quanta.