Quantum mechanics has maintained over the years the reputation of being “the most obscure theory.” It works perfectly well, but nobody seems to know why. It has been argued that the difficulty in understanding quantum theory is our failed attempt to force onto it a wrong conceptual scheme, wanting at all costs to think about the objects of the theory as, precisely, objects, i.e., entities having continuously actual spatiotemporal properties. This too restrictive spatiotemporal scheme is most probably at the heart of the problem, as also underlined by the Einsteinian revolution. So, what could be an alternative? Many thinkers have suggested that we must surrender to the fact that our physical world is one of immanent powers and potencies. Aristotle did so ante quantum litteram, followed by scholars like Heisenberg, Primas, Shimony, Piron, Kastner, Kauffman, de Ronde, just to name a few, including the authors, who were both students of Piron in Geneva. However, if on the one hand a potentiality ontology puts the accent on the processes of change, responsible for the incessant shifts between actual and potential properties, on the other hand it does not tell what these changes are all about. In other words, the metaphysical question remains of identifying the nature of the bearer of these potencies, or potentialities, and of the entities that can actualize them. It is the purpose of the present article to emphasize that the above question has found a possible answer in the recent conceptuality interpretation of quantum mechanics, which we believe offers the missing ontology and metaphysics that can make the theory fully intelligible, and even intuitive. In doing so, we will also emphasize the importance of carefully distinguishing the different conceptual layers that are contained in its explanatory edifice, as only in this way one can properly understand, and fully appreciate, the explanatory power it offers, without promoting undue reductionisms and/or anthropomorphizations.

I studied physics at the University of Lausanne, in the eighties of last century, where I had the chance of learning quantum mechanics from Gérard Wanders and Dominique Rivier, two students of Ernst Stueckelberg, and from Jean-Jacques Loeffel, a student of Pauli. Later, I was assistant to Constantin Piron, in Geneva, for his famous course in quantum mechanics. Constantin was also a student of Stueckelberg, as well as of Josef Maria Jauch. I then went doing my doctoral thesis with Philippe-André Martin, a college friend of Piron and also a student of Jauch. In other words, I had the chance of learning quantum mechanics from people who received the highest possible level training into it, and who were truly interested and invested in understanding it, both mathematically and conceptually. When in more recent times I got in touch with Diederik Aerts, after quite a long time I had not practiced physics anymore, I believe it is only because I had such authoritative teachers, providing me with the right perspective and mental posture, that a fascinating and fruitful collaboration could develop.