Thanks for your interesting reference to Timothée Parrique's thesis. I'll certainly read parts of his 700 pages, as the index shows it addresses some of the thorny issues.
In short, it looks like he too comes with a redefinition: "a normative theory of degrowth as de-economisation".
De-economisation, so using smarter values, other than monetary evaluations (economy), as fundamental values to guide society. Change the rules (values), change the game (society plays), change the results (more sustainability)...nothing very new about that insight, nor to disagree about.
Over the last century, thousands have written on this topic, some more eloquently than others. Christian Felber's 2010 "Gemeinwohl-Ökonomie" (Economy for the Common Good) is one of the best versions I've come across, bought, read and now support by being a member of www.ecogood.org/.
That still leaves the linguistic issue on the table.
You state: "The suggested societal /economic /environmental changes gathered under the banner ‘Degrowth’ are very diverse and intertwined. They are not covered by a short linguistic analysis of the word itself.". In short: it can mean all sorts of things and we are not going to use linguistic analysis to pinpoint it down to a clear and useful definition.....
That is where we differ fundamentally. As an engineer, I know that precise definitions form the foundations of everything that is built upon it. Mistakes lead to death. The same applies to the social science named Economy. Only there, deaths are over time, are far less visible and extremely few economists bother to equate correctly in QALY's.
Faulty definitions lead to useless results.
It's sad to see thousands waste their time using purposely opaque, politically inspired ambiguous terminology (like “degrowth”) instead of building a solid house together. The eco-movements always have had the hopeless habit of propelling prophets, all wanting to reinvent the wheel by themselves (Hinckel, Trebeck, Parrique, Raworth, etc, etc, etc) instead of collaborating towards a solid body of science-based decision-making. Hence the importance of finding the most useful definition of human progress, and my contribution to that vital discussion:
“Human progress can be defined as our ability to create and maintain high levels of future uncertainty“
In plain English, for example, if I burn fossil fuel today to fly on a holiday to Bali then there is nothing to show for it after the fact. Used up, its energy is converted into entropy. There are now fewer choices left and no future uncertainty was created with it. Yet that same fuel could also be used to build and operate a quantum computer. Useful today for solving the equations at hand and it creates a tremendous amount of uncertainty (compound impacts) for generations to come.
Uncertainty is, I believe, a useful principle to help guide society to make much wiser choices. It also prevents dogmatism as not all fossil fuel burning is a priori bad, some perhaps even good if you use far more intelligent metrics.
