I've recently found more than a few Stoics arguing against new ideas by saying, "that's not what Epictetus/Aurelius/Seneca said...so there." I assume these Stoics are all vegetarians.
[Musonius Rufus] often talked in a very forceful manner about food, on the grounds that food was not an insignificant topic and that what one eats has significant consequences. In particular, he thought that mastering one’s appetites for food and drink was the beginning of and basis for self-control.Musinous Rufus: Lectures and Sayings
The great Stoic teacher Musonius Rufus, claims that we should be lacto-vegetarians. In fact, he wants us all to be raw food vegetarians! Musonius had a variety of reasons to back up his claims. Our food choices are directly relate to our self-control. Our nature demands nutrition, but does not require pleasure. Also, meat makes people dim-witted. So, since Musonius was not only a headmaster of the ancient Stoic school but none other than the teacher of Epictetus, obviously all modern Stoics must become raw food lacto-vegetarians.
Nope. We don't have to adopt that practice. Modern Stoics can, and should, look into the reasoning Musonius Rufus lays out concerning food choices, but we can come to our own conclusions concerning what is appropriate to eat. And why can we do this? Is it because the subject of food is outside the scope of meaningful Stoic practice? No. Not in the least. Musonius is not just laying out ancient Roman nutritional advice. He is adamant that how we eat is a matter of virtue. It is not incidental. How we eat is just as important to wrestle with as whether or not we accept the Stoic concept of divinity, or the Stoic conception of the mind. The reason modern Stoics can disregard Musonius' point of view (or accept it) is because we are equal in authority to him, if we are equal to the task of thinking as a Stoic.
I do not bind myself to some particular one of the Stoic masters. I too have a right to form an opinion.
Stoicism has not come to us from anything greater than the human mind. The ancient writings we have available consist of some class notes, letters to friends, a journal, and explanations that were written down by rival schools in order to refute them. None of our fore-thinkers were holy men and what they wrote wasn't gospel. Some had original minds and others were simply repeating what they were taught, but all of them were regular people who happened to subscribe to a similar point of view. At times, "similar" might be considered a stretch.
Epictetus does not seem to be as adamant as his teacher was, concerning the subject of food. There's no record of him denying people the enjoyment of a perfectly cooked steak. Not to say he didn't believe in a proper diet. Chapter 46 of the Enchiridion mentions that we should not, "...talk about how persons ought to eat, but eat as you ought." So there is a right way to eat. For Epictetus, the Stoic diet was one of self-control and social grace.
...at a feast, to choose the largest share is very suitable to the bodily appetite, but utterly inconsistent with the social spirit of an entertainment.
Enchiridion Ch 36
Epictetus taught his students to be disciplined concerning food. The scene he usually set was a banquet where all the delicacies of Roman society would be available to choose from. Epictetus didn't ask that we avoid meat, he wanted us to avoid gluttony. He wanted us to take into account the social nature of a party, and understand that the food is there to share, not to gorge upon. This approach to food was similar to the approach to life that Epictetus advocated; act with discipline and take the good of others into account. Once you look past the specifics of Musonius's dietary advice, you find a similar message at the core of his teachings, "...since these and other mistakes are connected with food, the person who wishes to be self-controlled must free himself of all of them and be subject to none. One way to become accustomed to this is to practice choosing food not for pleasure but for nourishment, not to please his palate but to strengthen his body." He saw food as a daily means of testing our willpower. Will we eat wisely, or will we eat Twinkies?
My point is not to dwell on food, though I find the subject interesting. My point is that Stoics can, and do, hold different opinions. Even two Stoics as well respected as Musonius Rufus and Epictetus held divergent opinions and emphasized different aspects of the philosophy. These men were contemporaries and the entire philosophical school was handed from one to the other, yet their teachings still varied. We should expect that modern Stoics will approach the philosophy in a way that the ancients did not anticipate. In fact, with the quantity and quality of information we moderns have, we should be improving Stoicism instead of resting on the snippets of past thoughts that happened to make it to the present day. Of course, Stoicism can't incorporate just any belief whatsoever. If someone claimed that emotions are the best and sole guide to good living they couldn't claim that Stoicism backs them up. There are core ideas in our philosophy that truly matter. You can see that as Musonius and Epictetus approach food. One man is really specific about the Stoic diet, the other seems to have a wider view, but both are concerned with moral virtue and mental and physical well-being.
Quoting ancient philosophers is a great way to point out a long-standing argument, or emphasis a Stoic point of view, but the words of these men don't end our discussions. It frankly isn't Stoic to appeal to authority. The ancients are dead. We are here and alive. Stoicism, if it has any value, is a living philosophy. We are its philosophers. We have the right to an opinion. Stoicism has held up pretty well since 300 B.C.E. and we aren't going to break it with our poking and prodding. But we do know more about humanity and the universe than the ancient Greeks and Romans. We have the responsibility to incorporate that knowledge into the philosophy. For those of us who take up Stoicism as our way of life, the canon isn't closed. Do not accept what the ancients said without argument. Instead, improve their arguments. Build a more effective Stoicism. We're proof that Stoicism isn't done yet, so don't let others act like its last useful thought was written down in a scroll.