No ranked voting system can meet every ideal criterion once there are three or more choices

politicsWikipedia1951

No ranked voting system can meet every ideal criterion once there are three or more choices

the gist

Kenneth Arrow proved in 1951 that when there are more than two options, no ranked voting method can satisfy all the properties we would want from a fair group decision. One key property is independence of irrelevant alternatives: whether A beats B should not depend on some unrelated option C. The Marquis de Condorcet had earlier shown that majority rule can produce cycles, where A beats B, B beats C and C beats A. Arrow generalised that problem to every ranked system, including oligarchies and consensus procedures.

how it works

Ranked ballots only record which option each voter prefers to which. When three or more options are involved, these pairwise preferences can form loops, so no rule that turns them into one winner can also meet every fairness condition.

so what

The theorem explains why spoiler candidates appear in ranked elections no matter how the ballot is designed, so every voting system involves trade-offs. Arrow later conceded that rated systems, where voters give each candidate a separate score, escape his result because they use more information than rankings do. That is why score and approval voting are often discussed as alternatives.

has this happened before?

The same tension appears in Condorcet's 18th-century voting paradox, which Arrow generalised, and in modern debates over instant-runoff voting, where a candidate can lose after being ranked first by more voters. Each reform trades one desirable property for another.

Hampi was once one of the world's largest cities, until its Vijayanagara capital was destroyed in 1565

the gist

Hampi is a UNESCO World Heritage Site in Karnataka, India, with more than 1,600 surviving remains spread over 4,100 hectares. It was the capital of the Vijayanagara Empire from 1336 to 1565. Travellers from Persia and Portugal described it as a prosperous, wealthy and grand city with temples, markets and farms along the Tungabhadra River. By 1500 it was estimated to be the world's second-largest city after Beijing, and probably India's richest at the time. In 1565 a coalition of Muslim sultanates defeated the Vijayanagara Empire, its capital was conquered and destroyed, and the city was left in ruins. Hampi remains a religious centre, with the active Virupaksha Temple at its heart.

how it works

The city was built around a fortified core with temples, markets and water structures along the river, supplied by an extensive network of roads and waterworks. When the empire fell, the city was not rebuilt, so its stone monuments were left standing.

so what

Hampi shows how quickly a great city can vanish after a military defeat, and how a ruined capital can remain sacred. Its ruins give historians a view of medieval South Asia that few other sites can match.

fun fact

The name Hampi comes from Pampa, an old name for the Tungabhadra River.

From Wikipedia, the free encyclopedia · text CC BY-SA 4.0

Image: Wikimedia Commons

source: Wikipedia ↗

2 min

politicsshortCNA2:01

False allegations about Singapore’s hand in Indonesia’s markets and a made-up meeting

from CNA

CNA Verify has found close to 400 posts pushing falsehoods tying Singapore to Indonesia’s stock market rout and to a secret meeting that never took place. Together, they drew nearly 12 million views, and some were circulated by accounts that appeared to be working in concert, across multiple social media platforms.

Here’s how the disinformation campaign targeting Singapore was uncovered.

on YouTube: CNA ↗