‘Stoic’ ethics and reason (the position that reason is sovereign, is sovereign over the self, and is tested in living) is both reaffirmed and taken apart in the 16th and 17th Centuries. This can be seen in Montaigne and Descartes; Shakespeare’s plays and Cervantes’ Don Quixote. Descartes seems to parallel Cervantes in Discourse on Method, Part I when he refers to the fantastic stories that people may believe in enclosed in the world of books
But I believed I had already given enough time to languages and even to reading ancient books as well, and to their histories and stories. For talking with those from other ages is the same as travelling. It is good to know something about the customs of various people, so that we can judge our own more sensibly and do not think everything different from our own ways ridiculous and irrational, as those who have seen nothing are accustomed to do. But when one spends too much time travelling, one finally becomes a stranger in one's own country, and when one is too curious about things which went on in past ages, one usually lives in considerable ignorance about what goes on in this one. In addition, fables make us imagine several totally impossible events as possible, and the most faithful histories, even if they neither change nor increase the importance of things to make them more worth reading, at the very least almost always omit the most menial and less admirable circumstances, with the result that what's left in does not depict the truth. Hence, those who regulate their habits by the examples which they derive from these histories are prone to fall into the extravagances of the knights of our romances and to dream up projects which surpass their powers.
Descartes refers to the knights of romances and their influence on those who give too much importance to old fables and histories. Paying too much attention to such old books is like travelling away from our own country too much (this from Descartes who spent his life in the Netherlands, Bohemian and Sweden, rather than France). It is useful to travel so that we can compare customs, but if we travel too much we forget our on country and don’t belong anywhere. The reading of old books may take us away from the home of our own time. The interest in the value of comparing customs may come from Montaigne, though for Montaigne such knowledge comes from reading and writing at home, and sometimes from meeting people in France. The emphasis on journey into the past, and its dangers, marks a deep sense of the difference between past and present. A difference great enough that to be in a past time for too long is too become alienated from the present, and from our own mind.
Accidentally, or not, Descartes seem to describe the premiss of Don Quixote, the crazy poverty stricken minor aristocrat who reads so many books of chivalry, he thinks he is living in such a story full of magicians and giants. In this we see the breakdown of the ‘Stoic’ ideal of the sovereignty of reason, a sense that unreason is something pressing in on us, which is something Descartes deals with in the idea of the deceiving demon. With that thought, Descartes tries to push back into some deep core of the sovereign reason of the self, going well beyond the Stoic sense of self-regulation through reason. The defence of Stoic reason is just as much a recognition of its breakdown as a defence. Once reason is pushed back into this inner sphere of absolute rationality, it is losing its contact with the philosophy tested by how we live life. Descartes appeals to reason as an ethic of life, but that disappears in the purely internal struggle of mind to exclude deception.
Montaigne had already started this disintegration of ‘Stoic’ ethics and reason exploring itself. For Montaigne, reason does not just reflection on reason, or lead the will and the passions to a proper place under reason. Reason reflects on itself as something subjective and embedded in passions and will. The point becomes to understand the self as subjective self, and to understand others in their subjective selves better.