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Existential quantifier, used in logic to express existence

Existence is the state of having being or reality. It is often contrasted with essence, since one can understand the essential features of something without knowing whether it exists. Ontology studies existence and differentiates between singular existence of individual entities and general existence of concepts or universals. Entities present in space and time have concrete existence, in contrast to abstract entities, like numbers and sets. Other distinctions are between possible, contingent, and necessary existence and between physical and mental existence. Some philosophers talk of degrees of existence but the more common view is that an entity either exists or not, with no intermediary states. It is controversial whether existence can be understood as a property of individual objects and, if so, whether there are nonexistent objects. The concept of existence has a long history and played a role in the ancient period in pre-Socratic, Hindu, Buddhist, and Daoist philosophy. (Full article...)

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Cannonball

... that the Cannonball (pictured), a commuter train on the Long Island Rail Road, was once operated exclusively with parlor cars?
... that Piper Kelly secured her position as a competitor in speed climbing at the 2024 Olympics by reaching the final race at the 2023 Pan American Games, before winning the race?
... that a Bangladeshi government agency collected ৳6.5 billion (equivalent to US$150 million in 2023) from corruption suspects, but a court ruled it was illegal?
... that after Jamal Valizadeh was tortured in Iran, hid for six months, and escaped, he qualified to compete in the Olympics as a member of the Refugee Olympic Team?
... that the electoral victory of the Union for Democracy and Social Progress in 2018 led to DR Congo's first peaceful transition of power since its independence from Belgium in 1960?
... that in May 1983 British public health physician Spence Galbraith suggested withdrawing blood products made from blood donated in the U.S. after 1978?
... that Jack White released his sixth studio album unannounced by including unmarked vinyl copies of it with purchases made at Third Man Records stores?
... that Aniya Holder secured a spot at the 2024 Summer Olympics by winning a speed climbing competition, for which she had started training without even knowing that it was an Olympics qualifier?
... that the only known solution to the Erdős–Moser equation is 1 + 2 = 3?

In the news

Sheikh Hasina

Sheikh Hasina (pictured) resigns as the prime minister of Bangladesh and flees to India following anti-government protests.
Following a mass stabbing in Southport, far-right protesters riot across the United Kingdom.
The United States, Russia, and their respective allies agree to a prisoner exchange of 26 people.
Ismail Haniyeh, the political leader of Hamas, is assassinated in Tehran, Iran.

On this day

August 6

Street fighting during the Battle of Saint-Malo

1623 – After the death of Gregory XV, a papal conclave in Rome elected Maffeo Barberini as Pope Urban VIII.
1944 – World War II: Allied forces attacked German fortifications at Saint-Malo, France, beginning the Battle of Saint-Malo (pictured).
1979 – An earthquake struck along the Calaveras Fault near Coyote Lake, California, injuring sixteen people.
1997 – Korean Air Flight 801 crashed into a hill on approach to Antonio B. Won Pat International Airport in Guam, killing 228 of the 254 people aboard.
2011 – A series of riots broke out in several London boroughs and in cities and towns across England in response to the shooting of Mark Duggan by Metropolitan Police officers.

Ludwig Ross (d. 1859)
George Kenney (b. 1889)
Lucille Ball (b. 1911)
Edsger W. Dijkstra (d. 2002)

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Today's featured picture

ATLAS is the largest general-purpose particle detector experiment at the Large Hadron Collider (LHC), a particle accelerator at CERN (the European Organization for Nuclear Research) in Switzerland. The experiment is designed to take advantage of the unprecedented energy available at the LHC and observe phenomena that involve highly massive particles which were not observable using earlier lower-energy accelerators. ATLAS was one of the two LHC experiments involved in the discovery of the Higgs boson in July 2012. It was also designed to search for evidence of theories of particle physics beyond the Standard Model. This image shows the eight toroid magnet surrounding the calorimeter in the center.

Photograph credit: Maximilien Brice, CERN

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