“When we are no longer willing to die for the truth, there will be no truth anymore,” conservative German philosopher Peter Sloterdijk observed gloomily during a conversation with Slovenian philosopher-provocateur Slavoj Žižek in 2023, suggesting we might be living through the end of an era inaugurated by Socrates, “the first martyr for the European concept of truth.” Agnes Callard’s new book Open Socrates, which claims to make the case for a philosophical life, could not be more timely.