Helgoland

The same – it soon becomes clear – is true of Göttingen matrix mechanics: the mathematics gives predictions that are probabilistic, not exact. Quantum theory, just as much in Heisenberg’s version as in Schrödinger’s, predicts probability, and not certainty.

In the first decades of the twentieth century, it is the whole of European culture that no longer thinks we can represent the world in a simple and complete way. The anthropologist Lévi-Strauss understands that to study a culture is to change it; Freud understands that doctors cannot evaluate patients’ minds without affecting them. In Italy, betwee

Is it possible that a fact might be real with respect to you and not real with respect to me? Quantum theory, I believe, is the discovery that the answer is yes. Facts that are real with respect to an object are not necessarily so with respect to another.fn1 A property may be real with respect to a stone, and not real with respect to another stone.

Since measuring P alters X, measuring X first and then P gives different results than measuring P and then X. Hence in mathematics ‘first X and then P’ is necessarily different from ‘first P and then X’.77 This is precisely the property that characterizes matrices: order counts.78 Remember the single new equation introduced by quantum theory? XP –

The central thesis of Nāgārjuna’s book is simply that there is nothing that exists in itself, independently from something else.

Every time that something solid is put into doubt or dismantled, something else opens up and allows us to see further than we could before. Watching what appeared to be as solid as rock melt into air makes lighter, it seems to me, the transitory and bittersweet flowing of our lives.

What I see, in other words, is not a reproduction of the external world. It is what I expect, corrected by what I can grasp. The relevant input is not that which confirms what we already know, but that which contradicts our expectations.

The ‘anti-metaphysical’ spirit that Mach promoted is an attitude of openness: we should not seek to teach the world how it should be. Let’s listen to the world instead, in order to learn from it how to think about it.

At the heart of the ‘relational’ interpretation of quantum theory is the idea that the theory does not describe the way in which quantum objects manifest themselves to us (or to special entities that do something special called ‘observing’). It describes how every physical object manifests itself to any other physical object. How any physical entit