The Eternal Doorman

What a great circuit that drives this thermal printer! Here's the Nixie Counter video: Subscribe to Curious Marc .

This is between two and three kilometres down in the Arctic ocean, ... Subscribe to Uppsala Universitet .

38:41 See Pupina Plomer on the Children of Llullaillaco . Subscribe to Pupina Plomer . 

See Doomsday: Friday, 13 November, A.D. 2026. At this date human population will approach infinity if it grows as it has grown in the last two millenia by Heinz von Foerster, Patricia M. Mora and Larry Amiot. Subscribe to Anton Petrov .

I was recently told that it's unreasonable to expect anybody to read more than 500 words on any subject. Is that true? I often read more than 500 words, especially of books. But if I have to explain what words like epistemology and ontology mean as well, then that doesn't leave many words left. The best part of this lecture of Searle's is at 23:24 . I get into detail, with some examples from the 80s explicitly citing Searle in this post:  John Searle's Chinese Room Argument . One way to save words is to leave it up to the reader to look things up themselves, but very often they don't do that, even when you provide links for them to click: I suppose that's because links just lead to more words! See Collaborative Mathematics . Subscribe to Philosophy Overdose . 

You can read notes on Martin-Löf's lecture given in Padua in 1980 here:  Giovanni Sambin's notes on Per Martin-Löf's Intuitionistic Type Theory . See Andy Pitts on Intensional Setoids  for more on Minimal Foundations.  My comment : 40:32 Thorsten "You only need the notion of a type... Then I can explain a proposition,..." I remember when you did that a few weeks ago , and you explained it, but did anybody actually understand your explanation? I know I didn't!  And a reply :  @CMDR_K3YN  The problem is more about how to interpret 'statements like "a predicate of booleans is a function from bool (Boole?) to prop" ' See also from 40:43 where it's a collection of all such functions. Then Giovanni says his his idea of foundations is from the ground up, starting with propositions and sets! I honestly don't know how anyone can have a sensible conversation on this basis! I thought the standard procedure was to establish a metalanguage fir...

See Rachel Phillips and Luisa the Scottish Geologist .  Subscribe to  GEO GIRL . You can learn about her Scottish geology expeditions: https://www.scottishgeologist.co.uk/   Subscribe to Luisa the Scottish Geologist .

They were Inca human sacrifices made in the late fifteenth century. See  Children of Llullaillaco . In 1999 the almost perfectly preserved remains of these three children were discovered near the summit of the volcano. Since 2007 they have been exhibited in a specially constructed museum in Salta, Argentina. Descendents of these people still maintain the beliefs in the mountain deities to whom these sacrifices were made, ... Subscribe to Pupina Plomer . 

You really need these in computer science, chemistry, biology, physics and every other subject, because the potential for abuse by corporate, military-industrial power structures is enormous. See  Brady Haran Interview with Hugo Duminil-Copin  and  Brady Haran interview with Terence Tao .  Subscribe to  SAIR . 

See https://msp.cis.strath.ac.uk/msp101.html  I wish I had read this description of it before, because now it makes a heck of a lot more sense!  The simply-typed lambda calculus (STLC) gives us a nice Curry-Howard correspondence with propositional logic by treating the function arrow of STLC as implication. From this we can compute proofs as programs. But a natural question is then: what about predicate logics instead of propositional? Martin-Löf Type Theory (or Intuitionistic Type Theory) is a type theory based on predicate logic, with type constructions representing existentially quantified variables (Sigma) and universally quantified variables (Pi). We can also construct inductively defined families - W-types - as well-founded trees. Note that Martin-Löf's original paper was inconsistent due to having the type-in-type paradox, and that he later introduced a predicative version with universe hierarchies. In this introduction, we assume knowledge of the STLC and natural-deduc...