The Dunbar hypothesis isn't a limit on group size. It argues that an individual can maintain only some 100-200 regular social contacts. Yet if, as the article suggests, a Twitter user stabilizes at a maximum of 150-200 regularly-maintained contacts, they're using up most, if not all, of their Dunbar-space on Twitter alone. So does this mean that people with 150-200 regular Twitter contacts must lose their pre-Twitter real-world regular contacts, or that their pre-Twitter contacts must become Twitter contacts? That seems a bit much to assume without evidence.

I suppose further research will explore how the real-world-and-non-Twitter social life of the twitterati changes as they near their Dunbar limit on Twitter. Perhaps, as the article boldly suggests, "social networks [do] not change human social capabilities" (Conclusions, 7) and the Dunbar limit is indeed resistant to technological circumvention. But this article doesn't make that clear. By not examining the full social space of its subjects, the study does not actually address the possibility that Twitter has increased the number of regular contacts - of all types - that an individual can maintain.

The new glass-and-robots Mansueto Library, with its capacity for 3.5 million books, is right next to the older Regenstein Library, which still has roughly 4 million books in open stacks. Within a five minute walk of these two libraries is the Crerar Science Library with some 1.3 million books in open stacks. The two older "open-stacks" libraries, built in the 70s and 80s, aren't going away anytime soon. The majority of the University of Chicago's collection will therefore continue to be easily browsable by students and faculty alike for decades to come.

The new library will house rarely consulted books and the tens, if not hundreds, of thousands of serial volumes in the University's collection - journals and pamphlets which have already been digitized and need only rarely be consulted directly. The Mansueto is therefore more like a stylish reading room on top of a warehouse of rarely-consulted books - remote storage with five-minute retrieval times. http://news.lib.uchicago.edu/blog/2011/05/16/mansueto-library-celebrates-books-in-digital-era/

The new building is right next door to the old building, and will be used to store rarely accessed books. The old building is still in use, and holds several million volumes.

Not a single instance? What do you do for a living? Do those in your profession ever interpret a difficult or unclear piece of writing? Do they judge subtexts, written or verbal? Does your profession have a history? Do members of your profession allocate finite resources in society at large? Do they face government certification? Are they subject to government legislation?

I hope you'd agree that your opinions about what's useful for your profession, and what's useful for your sister's profession, shouldn't be taken as the standard for all professions. Some professions don't use literature, history, politics, or music overtly, or frequently. But you're overreaching to assert that because you don't use them, and because you think your sister doesn't use them, that they're mere "enrichments" for everybody.

I'm afraid not. A militia and an army were very different notions in 18th-century Britain and the colonies. A militia was composed of the mass of the adult male population which received semiprofessional training once or twice a year. They were rarely "well-regulated," which meant well-organized or well-trained in the arts of war. An army was a professional force of soldiers, paid, maintained, and trained by the state.

See the 1789 debate on the Second Amendment where there were clear distinctions made between standing armies paid and directed by the state and militias composed of the mass of the people. http://www.constitution.org/mil/militia_debate_1789.htm

In the hundred years of debate from the 1680s to 1800 about the necessity of a standing army in peacetime, it was the army that was the agent of government tyranny, not the militia.

You're right than the Second Amendment needs to be read in context, but the claim that a standing army was or was thought of as a well-regulated militia doesn't fit that context.

There is a clear distinction between a militia and a standing army in late-17th through late-18th political discussion both in Britain and in its colonies. There are dozens, if not hundreds, of pamphlets from this hundred-year span which debate the wisdom of the creation and maintenance of a standing army in times of peace. This debate was almost uniformly cast as choice between (1) reliance upon a militia for peacetime security and (2) peacetime maintenance of a standing army alongside the militia. To claim that a standing army was referred to or thought of as any sort of militia, and, in particular, that the phrase "a well regulated militia" refers to a standing army, is inconsistent with this longstanding tradition of 18th-century political debate.

See, for example, the discussion at http://www.constitution.org/mil/militia_debate_1789.htm, which makes clear that contemporaries involved in the debate on the Second Amendment distinguished sharply between a militia and a standing army. To quote the Virginia Convention: "That the people have a right to keep and bear arms; that a well regulated Militia composed of the body of the people trained to arms is the proper, natural and safe defence of a free State. That standing armies in time of peace are dangerous to liberty, and therefore ought to be avoided, as far as the circumstances and protection of the Community will admit..."