According to the Roman stoic philosopher Epictetus, "Some things are up to us and others are not.  Up to us are opinion, impulse, desire, aversion, and, in a word, whatever is in our action.  Not up to are body, property, reputation, office, and, in a word, whatever is not our own action."

Epictetus' advise was to care for those things that are up to us, and to not worry about those that are not.  We can, according to Epictetus, manage our own opinions, but not those of others.  While we cannot avoid old age, sickness, and death, those inevitable conditions of the body, we can control our minds, and choose what we can accept and what we can't.

This teaching, in my opinion, accepts the duality of mind and body - the body is a physical thing, outside our control and subject to the forces of nature, while the mind, although dependent on the body for sustenance, is non-physical, within our control, and subject only to the forces of our own reasoning.

I've been a student of Zen long enough to instantly become suspicious the instant I sense a dualistic concept.  The brain is an organ of the body, and functioning as designed by nature it squirts out thoughts in the same way that the stomach, say, squirts out digestive juices. According to the Buddha, our thoughts, our reasoning, our very minds, are nothing more than these secretions of the brain, and are not separate from the body.  The Buddha, then, would have questioned Epictetus about how if our bodies were outside of our own control, how our opinions, impulse, desire, and aversions could be considered within our control, as they are merely products of our out-of-control bodies.

Epictetus seems to rely on the Platonic model of reason, that uniquely human ability to judge and discern our thoughts, as the driver of our emotions, desires, and aversions.  Plato used the metaphor of emotion as a chariot and reason as the horse driving the chariot.  We look at the data, make a rational decision on the best course of action, and then act accordingly.

Later philosophers (e.g., David Hume) and psychologists (notably Freud) challenged this model.  Our subconscious minds have their own desires and aversions, and our faculty of reason merely looks for excuses and rationales to support and defend the a priori decisions our subconscious had already made before we were even aware of it.

In this model, the subconscious mind is like an elephant, going wherever it wants based on its own desires and attractions, and the rational mind is like a monkey on top, pretending to steer but really just finding reasons and arguments to defend what the elephant is going to do anyway.  Reason does not drive our decisions - reason is used to justify our subconscious choices.  The intuitive, emotional elephant drives the thinking of the rational monkey, not the other way around.  In other words, we make an intuitive decision and then look for data and logic to support it.

Epictetus maintained that we can use logic and reason to determine what is within our control and what isn't and then act accordingly, and that our lives would be better if we didn't try to influence what we can't control and instead tended to only those things that we can, but later philosophy and science showed that  Epictetus' teachings are just another tool that the rational monkey can use to justify the actions of the intuitive elephant. 

This, however, is not a refutation or a dismissal of Epictetus - all ethics, philosophy and morality are just tools in the monkey's toolkit, and Epictetus helpfully shows us how to accept things with which it may be difficult to live.  It is not a shortcoming of the wrench that driving a car cross-country won't allow us to escape the limitations of our own life, but if you want to maintain and repair your automobile, Epictetus provides us some handy tools for the job.