Great food for thought, as always, Massimo. I agree with your positive view on human nature. However, your defense of Stoicism has some holes. The way I see it, the fundamental issue is that Stoicism asks us to devote our life to cultivate Virtue over anything else, including our own happiness. This is a tall order, so it needs a strong rational justification. And yet, even a clear definition of what is Virtue is lacking. In this article you offer three different definitions of Virtue and state that they are the same. But they are quite different.
First, you say that Virtue is “following nature”. It is not clear what “nature” means in this statement. From what you say, the ancient Stoics linked nature with Logos, the underlying rational force in the cosmos. Hence, following this kind of nature ties our action to an universal goal, much in the same way that monotheistic religions like Christianity put our lives at the service of God. As I explained in earlier comments to your writings, I am more sympathetic to the idea of Logos than you are. But if you and the modern Stoics discard it, then you are left with defining nature as human nature. I agree with you and Steven Pinker (in “The Blank Slate”) that there is a biological, innate human nature that makes us different from animals. However, in and by itself this human nature is not inherently good and therefore worthwhile to be followed. Something else is missing. Thus, even things like moral indignation (the origin of altruistic punishment) have been responsible for a lot of atrocities in human history, like witch hunts, burning of heretics and prosecution of homosexuals. I know that you are going to reply that such emotions need to be tempered by reason, but this leaves us at the starting point, because any reasoning has to be based on some fundamental values. If these values are Virtue, we are back at the beginning and the reasoning becomes circular.
Second, you say that “following nature” is the same as “following the facts”. I am all for science and abiding by evidence, but most scientific facts tell us nothing about how we should act. If anything, they would tell us to satisfy our needs and desires, which is identical to search happiness and not some ill-defined Virtue.
Third, you define Virtue as reason. This is not the same as “following (human) nature”, because rationality is only a small part of what makes us human. And it is not the same as “following the facts”, because facts are not inherently reasonable. By itself, reason does not provide us with goals. Only when we have defined these goals we can use reason to attain them.
So, ultimately, the modern formulation of Stoicism appears to be nihilistic. Meaning is defined as following Virtue but there is no satisfactory, or rational, definition of Virtue. Yes, we can work towards a greater social well-being, but how is this different from working towards our personal well-being? At the end, both things seem to be pointless in an Universe without Logos. We may as well work towards our personal happiness, or try to split our efforts between our own goals and the goals of our society. But this seems to be different from what Stoics are advocating.