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Second-order logic explained in plain English (lambda-the-ultimate.org)
57 points by shawndumas on June 12, 2015 | hide | past | favorite | 16 comments


It avoids mathematical formulas, okay, but that doesn't make it plain English. I read the first sentence at least three times and I am still not absolutely sure that I didn't miss something and it says something (slightly) different then I think.

I then only read a couple of sentences every couple of pages and the impression I got was that it is essentially as technical as any axiomatic definition just without the clarity and compactness of mathematical formulas.


Shouldn't this be pointing to the paper being discussed?

https://www.academia.edu/11975482/Second-order_logic_explain...


If you would like to download the paper without having to sign up to academia.edu, the abstract and a download link can be found here: "http://philpapers.org/rec/CORSL-3".


Your link seems to be broken (due to a trailing %22). This one works: http://philpapers.org/rec/CORSL-3


Sorry. I've put links inside double quotes before, but this is the first time the second double quote has been tacked onto the link.


Thank you (to you and konz (https://news.ycombinator.com/item?id=9705512 ))! I've been wanting to read this, but not enough either to sign up at academia.edu or to read it through that site (I like to read in Preview or on paper). Coming from math, where the arXiv is deservedly the gold standard, I've never understood why other disciplines use these terrible aggregators.


Yeah. Shitty blogspam posts need to die die die.


LtU is hardly shitty blogspam. Commenters there are mostly PL researchers and the discussion is usually highly technical and gives better context to papers.


I agree; but, unfortunately, at the moment, the discussion to which I was looking forward seems mostly to be the usual contribution from Hewitt (http://lambda-the-ultimate.org/node/5170#comment-86211 and, more generally, http://lambda-the-ultimate.org/user/8437/track ), who likes to explain why every endeavour except his ActorScript is foolish and misplaced.


I don't care about the reputation of the site in general. My heuristic is as follows: is this link providing any editorial context for some original source? If the answer is no, I classify the link as blogspam.

This link right here is shitty blogspam. It deserves zero clicks.


Dunno, there are some blogs which are quite reputable and often you will find interesting comments on their site. I wouldn't paint it as black and white.


Maybe I'm being picky, but I interpreted the title to mean "explained in [less that 75 pages of] plain English".

Attention span... draining... strength... procrastination fading... closing... tab


15 pages. The document excerpt starts from page 61.


> No matter what human action you consider, if everyone does it to everyone doing it to them, then everyone has it done to them by everyone to whom they do it

I'm finding this incredibly hard to parse, yet feel like the point should be quite simple, and the paper seems to get harder from there.

> if every given proposition bears it to every proposition bearing it to the given proposition, then every given proposition is borne it by every proposition the given proposition bears it to.

I don't want to knock someone's efforts at this, but perhaps this is only a "plain english explanation" to someone who already understands the topic at hand?

In all, it reminds me of "the missile knows where it is": https://www.youtube.com/watch?v=bZe5J8SVCYQ


Try substituting a particular action like "hit." It becomes easier to imagine:

> If everyone hits everyone who hits them, then everyone is hit by everyone whom they hit.

Or: "If everyone hits back, then everyone gets hit back."

The other example is the same, but with propositions instead of people and "bearing" instead of hitting/unspecified human actions.


Thanks, that is clearer.




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