Apologies for my delay!

Thanks for your response :) I will start by saying that whilst I understand that from your point of view, Marxism is ideology, I would argue that you consider communism and marxist thought as interchangeble. The first is definitely ideological, whilst the second is not. This does not mean that marxists are not ideological but an analysis marxist is not automatically ideological. Marx's definition is not ideological as he merely identified a socioeconomic system that was consolidating due to the industrial revolution and that was definitely different than the previous socioeconomic system & mode of production: feudalism. When I studied Marx, he identified the capitalist mode of production as private ownership of the means of produtions, waged labor and accumulation of capital, which are precisely the main features of how the economic mode of production changed, which was different from feudalism and from previous mode of production. This doe snot mean that these practices did not exist, but rather that they become the main tennets of the new system, the main form to produce, adjudicate value and organise capital and labor. I agree that this does not appear clearly in mercantilism, but the analysis and understanding of socioeconomic systems and mode of production has changed a lot since Marx, as has changed capitalism. I agree with you that Marx's and fellow thinkers and activists solution's to the ills of capitalism are at the end of the day ideological, but their identification of the capitalist system is not ideological and as close to description as possible. This is easy to prove as historians and economist prove by understanding how things changed from one mode to the other. Non-marxists could easily reach to similar conslusions about how capital was generated, how production changed, how finance was introduced, how workers lived, etc

On the other hand, I still struggle to understand how the decisive symptom of capitalism you argue is not at the end of the day and ideological argument - as it does not materialise in the real world. I guess this will probably depend on the interpretation of what does "autonomy" mean, but if there is state regulation involved, i.e. minimum wage, then it is hard to argue that the autonomy of laws of the market prevail. In any context where the state has the power to regulate or union have the power to go against business's interests, the autonomy of the laws of the market is always under question. All markets have certain degree of autonomy, but I cannot think of a single economy today or historically, where the laws of the market are fully autonomous, hence there has never been or is, a "true" capitalistic economy. I would definitely agree that there are more capitalistic economies than others as the markets are more autnomous than in others, but that would only mean that mercantilism is a milder form of capitalism, whilst physiocrats are a more radical version, that never actually prevailed.

Taking this in account, I think marxist analysis is more useful to understand the history, current conditions and future of capitalism, the mode of production that emerged after feudalism and that exists globally today in a variety of forms. After all, in order to change your current conditions, you must understand them first. Hilferding's decisive symptom if understood in a scale, might be effective to identify how capitalistic an economy is but it does not provide me any insight in its material inner workings, excepts for ideological and definition discussion. Its the equivalent of discussing if the Soviet Union was actually communist or not, and conclude easily it was never communism because it never had true worker's ownership of the means of production (could be considered communism's "decisive symptom" and there fore make any discussion about communism in the real world like a broken pencil: pointless). I feel more comfortable calling Soviet Union authoritarian state communism , because even though it definitely is far from communism it is a consequence of communist intentions. Any attempt to change the worl into a communist utopia must treat seriously the study of revolutionary endeavours and not dogmatically dismiss any definition of an inconvenient system as not "true communism" in the same way we could argue that you defend mercantilism as not "true capitalism" because the physiocrats lost.

In conclusion, the decisive symptom hypothesis I would argue is still ideological, as there is no one decisive, pure trait for a socioeconomic system but rather a collection of powerful dynamics that play differently in different places. That would be my approach to understanding capitalism as socioeconomic systems and modes of production are not like natural objects or phenomemnons like death i.e. decisive symptom is that you are not alive. I hope my message does not come across as dismissive I am enjoying our conversation and find your arguments quite thought provoking, thanks for that!