Experimental Open Thread (Now Closed)
A space for conversation near the end of Arc 2
Welcome to The Blackthorn Hedge. This first Sunday of the month I’d like to try an experiment as usual, and for this one – since I’ve been sending out a lot of long letters and Halloween has had many of us more occupied than usual – I’d like to try an open comments thread rather than another full letter.
Please treat this as an opportunity to ask a question, make a comment, or just bring up any topic you’d like to discuss in the comments, particularly anything related to a prior letter or note that I’ve written, but not necessarily. Anything in philosophy, political or economic history, natural science, or mathematics might work.
I usually say “I welcome all respectful comments, messages, and other engagement” at the end of my letter preambles and I’ll say it again now, but a few extra words might help. First, if you’d like to assert a position, please keep in mind my Assertion Hierarchy, and second, if you’d like to disagree with someone else’s position in a reply, please mind Paul Graham’s Disagreement Hierarchy. Please stick to words and phrases that the broad audience of readers here can understand without outrage or provocation, i.e., please minimize emetic speech, and please don’t feed pests.
I’ll feel free to delete comments that seem disrespectful of others or of the space; I’ll explain my decision after deletion for each of the first twenty deletions and for each individual’s first deletion. I might or might not give warnings and I may also block freely, though I don’t expect it to be an issue this time.
All that policy said, I’ve been very happy with the comments I’ve been getting on the last several letters! I hope an open thread is timely and that we’ll see some good discussion. The Notes side of Substack may make it redundant, but let’s run the experiment.
End of experiment update:
The experiment’s run its course, with an interesting result: this generated few comments, but a good number of personal messages. It looks like Notes doesn’t just replace these sorts of posts for my readers, but it also actively discourages them, like Something Awful once discouraged basic blog commenting for a lot of people it harassed 20 years ago. The discovery and availability of comments to Notes is “too good,” and people do not want to engage it. I’m glad to have learned that.



Open sub-thread 2: Is there any recent new natural science you’re excited about?
I’ve been interested to see continued progress on the “amplituhedron” formalism in particle physics, recent Quanta article connecting it to origami here: https://www.quantamagazine.org/origami-patterns-solve-a-major-physics-riddle-20251006/, and interstellar comet 3I/Atlas has been very surprising, some latest coverage here: https://www.scientificamerican.com/article/the-interplanetary-race-to-study-interstellar-comet-3i-atlas/
Open sub-thread 1: As I close out Arc 2 here, what are your thoughts on what I’ve been doing so far and what I should do next?
(Explanation of the arcs: https://blackthornhedge.substack.com/p/laying-the-hedge-arc-1)