In his Davos speech earlier this week, Canadian prime minister Mark Carney warned that the rules-based international order was fraying, replaced by a harsher logic where “the strong do what they can, and the weak suffer what they must.” This aphorism, he noted, belonged to the ancient Greek writer Thucydides, who asserted it his History of the Peloponnesian War.

In the history’s Melian dialogue, Thucydides imagines that the Athenians state they can take the island of Melos because “questions of justice apply only to those equal in power” and “the superior exact and the weak give up”. It’s often been assumed that Thucydides believed the true nature of the world is that “might makes right,” but in this piece, classics expert Neville Morley explains how that interpretation isn’t quite right.

Carney’s invocation of Thucydides was pointed. His talk of “great powers” and “hegemons” was clearly about the recent aggressive American foreign policy approach in Venezuela and territorial ambitions for Greenland. On The Conversation Weekly podcast, Greenland ice expert Paul Bierma explains what a lost US military base beneath the ice reveals about the island’s real strategic value.

Elsewhere on the site, we warn against AI’s impact on your ability to think and offer tips on how to claw some of the brain power back. We also explore the mystery and science behind why onions and chips keep washing up on England’s south coast.