Helgoland by Rovelli, Erica (ebook reader below 3000 .txt) 📗

“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 disposition to manifest itself in one way or another.102 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.103

This, I believe, is what we have discovered about the world with quanta.

WITHOUT FOUNDATION? NĀGĀRJUNA

This way of understanding the central discovery of quantum mechanics is rooted in the original intuitions of Heisenberg and Bohr, but was formalized in the mid-1990s with the birth of the “relational interpretation of quantum mechanics.”104 The world of philosophy has reacted to this interpretation in various ways: different schools of thought have framed it in different philosophical terms.

Bas van Fraassen, one of the most brilliant contemporary philosophers, gave it an acute analysis within the framework of his “constructive empiricism.”105 Michel Bitbol gave it a neo-Kantian reading.106 François-Igor Pris read it in the perspective of contextual realism; Pierre Livet in terms of the ontology of processes.107 Mauro Dorato has inserted it into structural realism, according to which reality is made up of structures.108 Laura Candiotto has defended the same thesis.109 I do not intend to enter into the debate among different currents of contemporary philosophy. I only add here a few pointers, and tell a personal story.

The discovery that quantities we had thought of as absolute are, in fact, relative instead is a theme that runs throughout the history of physics. Beyond physics, relational thinking can be found in all the sciences. In biology, the characteristics of living systems are comprehensible in relation to their environment formed by other living beings. In chemistry, the properties of elements consist of the way in which they interact with other elements. In economics, we speak of economic relations. In psychology, the individual personality exists within a relational context. In these and many other cases, we understand things (organisms, chemicals, psychological life) through their being in relation to other things.

In the history of Western philosophy, there is a recurrent critique of the notion that “entities” are the foundation of reality. It can be found in widely different philosophical traditions, from the “Everything flows” of Heraclitus to the contemporary metaphysics of relations.110 Only in the past few years, books of philosophy have come out with titles such as Formal Approach to the Metaphysics of Perspectives and Viewpoint Relativism: A New Approach to Epistemological Relativism Based on the Concept of Points of View, to name just some most recent examples.111 In analytic philosophy, structural realism is based on the idea that relations come before objects.112 Michel Bitbol has written From inside the World: For a Philosophy and a Science of Relations.113 Laura Candiotto and Giacomo Pezzano have published a book with the title The Philosophy of Relations.114

But the idea itself is ancient. In the Western tradition, we can already find it in the later work of Plato. In the Sophist, Plato considers the fact that his atemporal Forms must be able to enter into relation with phenomenal reality to make sense, and ends up putting into the mouth of the central figure in his dialogue, the Stranger from Elea, a famous, completely relational (and not very Eleatic) definition of reality: “I say therefore that what by nature can act on another or suffer even the slightest action from another, however insignificant it is, and even if it happens only once, this alone can be truly real. I therefore propose this definition of being: that it is nothing if not action (δύναμις).”115 As is not uncommon, someone might be tempted to think that Plato has summed up in a phrase everything that there is to be said on the subject . . .

Even this very incomplete overview is sufficient to show how recurrent is the idea that the world is woven by relations and interactions more than by objects.

Take an object: this chair that I see in front of me. It is real and stands before me, objectively, no doubt about it. But what does it mean, exactly, that this whole is an object, an entity, a chair, real?

The notion of a chair is defined by its function: a piece of furniture designed for us to sit on. It presupposes human beings who sit down. It’s about the way we conceive of it.

This does not affect the fact that the chair exists right here, objectively. The object is still here, with its obvious physical characteristics of color, hardness and so on. But even these characteristics exist only in relation to us. Color comes from the encounter between the frequencies of light reflected from the surfaces of the chair and the particular receptors in human retinas. It is not about the chair: it is a story between light, retina and reflection. Most other animal species do not see colors as we do. The frequencies themselves emitted by the chair emerge only from the interaction between the dynamics of its atoms and the light that illuminates them.

The chair, still, is an object independent of its color. If I move it, it moves as a whole. Strictly speaking, not even this is completely true: this chair is made of a seat that rests on a frame, which rises when I pick it up. It is a set, an assemblage of pieces.

What is it that makes this assemblage of pieces a single object, a unit? Effectively, it is little more than the role that this combination of elements plays for us.

If we look for the chair in itself, independently of external relations, and especially of its relations to us, we struggle to find it.

There is nothing mysterious about