Four truths and eight practices, read as things to do rather than things to agree with — with the research stated at the strength it actually holds, which in this field is a good deal weaker than advertised.
Buddhism is not one thing. It is a family of living religions spanning two and a half millennia, with multiple canons, monastic orders, devotional practice, elaborate cosmology, and vigorous internal disagreement about nearly everything — including what the eight factors discussed here actually mean. This series uses one early textual stream, the discourses preserved in Pāli, and leaves the rest alone.
Two translation problems are worth knowing at the start, because the English is doing damage. The eight factors are conventionally translated as “right.” Sammā can also suggest proper, complete or fully developed, so “right” should not be heard merely as rule compliance — but neither should the ethical judgment be translated away, since the path is unmistakably normative. And they are not stages. They are conventionally grouped in three divisions and understood as mutually supporting, which is why the traditional image is a wheel rather than a staircase. These twelve essays are not levels.
What is missing is the frame: rebirth, karma across lifetimes, a monastic community, a teacher, and a goal that is not about feeling better. There is a serious argument, made from inside Buddhist communities, that secular adaptation takes the techniques, discards the ethics and the aim, and returns the remainder as a tool for tolerating conditions that should be changed. I think that argument is largely right, and this series is an instance of what it describes. Saying so is not an exemption.
On the research: this is the field with the most published evidence in the whole library and the most serious quality problems — small samples, weak controls, self-report, publication bias, much of it documented by contemplative researchers themselves. Quotations from the discourses follow Bhikkhu Sujato’s translations, cited by the standard sutta reference. Where the popular version of a finding outruns the finding, I say so in the essay rather than collecting the caveats here. Several well-known studies in this area have been substantially revised or reinterpreted by their own authors, and I have used the corrected versions.
One safety note. Intensive meditation is not uniformly benign, adverse effects are documented, and the practices here are separated from the teacher and community that would normally catch them. The seventh essay says more.
Read them in order if you want the argument — four truths, then eight practices. Or take whichever title describes your week.