There have been considerable distractions ���

So I have had less time and inclination for logical matters in the last couple of weeks. And much less patience too. I did, for example, look at a recent Cambridge Elements on logic; but it struck me as really very badly written. I also, for example, found myself struggling though a couple of recent papers by an author I have admired; again, this ex-editor of Analysis would never have let them pass in their current state. No names, no pack drill: but rather depressing, actually.

But mainly, when I have been in a logical mood, I have been re-reading Luca Incurvati���s excellent Conceptions of Set and the Foundations of Mathematics (CUP, 2020). I did have it in mind to rework some old blog posts on Luca���s book. But the more I re-read those posts, and the more I re-read some of the rich surrounding literature, the more embarrassingly thin (and occasionally misguided) my efforts seemed. Also rather depressing, in a different way! So I will abandon that plan and just repeat the Study Guide���s warm recommendation for Luca���s book.

Let me also recommend again a set-theoretic trilogy that I have just re-read. This is perhaps the most important recent work on the idea of the cumulative hierarchy of sets, Tim Button���s tour de force on what he calls Level Theory (bringing, it seems, to their ideal form set theories due to Scott, Montague, Derrick, and Potter ��� the first paper, Level Theory Part I, is key). I have been trying to write some introductory notes on this, to make the pivotal concepts Tim defines (potentiation, history, level etc.) strike us as even more compellingly natural: but this is proving a bit more troublesome than I hoped ��� reflecting on me, rather than Tim���s achievement, I am sure.

��� Must do better if I can, when I feel less distracted!