> Why as an “anti-dogmatist” should Sextus be unable to identify that some things are absurd or impossible? <

Well, because to say that something is absurd or impossible, particularly when concerned with non-evident matters, strikes me as eminently dogmatic.

> Aren’t we in the everyday course of life able to identify some things as impossible? <

Are we? Can we exclude that we are hallucinating, or that we are suffering from a brain injury that alters our perception of reality and ability to reason?

> Would it not be more productive to investigate rules for daily life? <

Certainly. But is it necessary to make statements about what is possible or impossible? What good does it do?

> my wife, Mary Braun, is a fan of Stoicism and has written several articles on it <

Didn’t realize she is your wife! Yes, I read that article.

> So much of what people find valuable in Stoicism is the spiritual exercises. I think these are wonderful; however, almost none of them depend upon Stoic dogma. <

I don’t think that’s the only thing at all. People find Stoicism attractive because it provides them with an internally coherent and actionable system of belief. What you are saying is similar to claiming that there is no value in Buddhism because people can meditate without embracing the four noble truths.

> I think it would be better for you to say why you think conversations in that group are unsatisfactory rather than me taking us off into a tangent on Epictetus <

I wouldn’t make a general statement about conversations in that group. However, I have encountered very dogmatic, even intolerant individuals in the group. Does Stoicism make them so? More likely they have always been like that and Stoicism is yet another outlet for their dogmatism and intolerance.

This, of course, is an empirical matter, but the sort of preliminary data collected over the years by Tim LeBon seem to indicate that practicing Stoicism has a beneficial, not deleterious effect.

> What you are suggesting as your project sounds to me to be eclectic, not skeptic. It just borrows stuff from other schools, providing little on its own. <

I see Skepticism as a philosophical attitude, not a philosophy. So it is obviously conducive to eclecticism, a la Cicero. As for offering something new, that’s not a requirement, I think. Picking and choosing in novel ways is in itself new, even if none of the individual elements are. Stoicism also started eclectic, and very few ideas are entirely new to it, many are borrowed from Plato, the Cynics, the Megarians, and so forth.

But if you are looking for something new / modern to add to ancient Academic Skepticism, then for instance consider the possibility that the qualitative notion pithanon may be made quantitative and rigorous by adopting modern Bayesian epistemology. Which has very practical applications.

> Aren’t many of the popular books on Hellenistic philosophy implicitly pitched to such skeptics already? <

No, I don’t think so. I’ve known plenty of people within the scientific skepticism community for decades, and I don’t recall once anyone mentioning Hellenism, Cicero, Carneades, and so forth. But they should!

> Have you looked much into what Karl Popper had to say about the ancient Greek philosophers? <

Yes, but years ago, I should take a fresh look. Of course, Popper’s criterion of falsifiability did not hold up to scrutiny…