The Stoic motto is to live in agreement with nature. It’s common to sum up the motto as, “live rationally and virtuously.” That’s basically what it means. But there’s more to it. The foundation of Stoic morality isn’t mere reason but reason and love, a form of rational love. In fact that is what virtue is, a love taken to its logical conclusion, philanthropy (love of man).
One could argue the Stoics were both moral sentimentalists and moral rationalists. Think back to the Stoic Hierocles. Hierocles made the observation that in the course of our development, if everything goes right, we begin with self-love, then we love our family, then we love our community, and finally we love all of humanity. Humans begin with moral sentiment when they’re in infancy and then develop philanthropy later in life. Philanthropy is what virtue basically is. Living in agreement with nature is to love everyone. We have a rationally guided system of moral development.
If this is nature and it progresses in this fashion, shouldn’t we just go with the flow? Doesn’t sound like one needs to put much effort into life if one will become virtuous eventually. Nature just ain’t that simple. To follow nature in the Stoic sense, one must combat some external forces that halt this natural development.
This is where Newtonian physics enters the picture. Sir Isaac Newton was able to describe falling bodies under influence of a net force by removing combative features in nature such as air resistance. In a vacuum, everything will fall to Earth, despite varying masses, at exactly 9.8 meters per second per second. When a cannon ball is shot from a cannon, one can pretty much ignore air resistance and predict where it will fall based on angle of trajectory. Only if one drops a feather is it difficult to ignore air resistance.
I think the whole principle of ignoring external factors is what the ancient Stoics meant by following nature. The Stoics meant to imagine how humans would develop if one were to assume things go well. Similar to how in Newtonian mechanics, one would remove resistance, in Stoicism one conceptually removes abuse from parents, removes influence from a materialistic society, and removes all the resistances of the world that can and will halt development. By conceptually removing these “resistances,” one can focus on the physics (nature) of how humans can grow from self-love to love of humanity. The problem is one has to deal with these resistances, just as physicists have to deal with air resistance, so the ancient Stoics created mental strategies to get humans back on track. NASA deals with many of the complications with space but NASA does have the luck that space is a vacuum. In a vacuum, Newton’s laws work perfectly. In air, not so much. The Stoics knew that to follow nature, meant to create a vacuum in one’s passions. A vacuum in one’s passions meant to be free from the influence of externals. If one could minimize the influence of external events on one’s well-being, then one could truly follow nature. One can truly follow nature just as NASA can easily predict where probes will go in a vacuum.