Graham Westbrook. In 1950, Ayer attended the founding meeting of the Congress for Cultural Freedom in West Berlin, though he later said he went only because of the offer of a "free trip". He gave a speech on why John Stuart Mill's conceptions of liberty and freedom were still valid in the 20th century. Together with the historian Hugh Trevor-Roper, Ayer fought against Arthur Koestler and Franz Borkenau, arguing that they were far too dogmatic and extreme in their anti-communism, in fact proposing illiberal measures in the defense of liberty. Adding to the tension was the location in West Berlin, together with the fact that the Korean War began on 25 June 1950, the fourth day of the congress, giving a feeling that the world was on the brink of war. From 1959 to his retirement in 1978, Ayer held the Wykeham Chair, Professor of Logic at Oxford. He was knighted in 1970. After his retirement, Ayer taught or lectured several times in the United States, including as a visiting professor at Bard College in 1987. At a party that same year held by fashion designer Fernando Sanchez, Ayer confronted Mike Tyson, who was forcing himself upon the then little-known model Naomi Campbell. When Ayer demanded that Tyson stop, Tyson reportedly asked, "Do you know who the fuck I am? I'm the heavyweight champion of the world", to which Ayer replied, "And I am the former Wykeham Professor of Logic. We are both preeminent in our field. I suggest that we talk about this like rational men". Ayer and Tyson then began to talk, allowing Campbell to slip out. Ayer was also involved in politics, including anti-Vietnam War activism, supporting the Labour Party (and later the Social Democratic Party), chairing the Campaign Against Racial Discrimination in Sport, and serving as president of the Homosexual Law Reform Society. In 1988, a year before his death, Ayer wrote an article titled "What I saw when I was dead", describing an unusual near-death experience. Of the experience, he first said that it "slightly weakened my conviction that my genuine death ... will be the end of me, though I continue to hope that it will be." A few weeks later, he revised this, saying, "what I should have said is that my experiences have weakened, not my belief that there is no life after death, but my inflexible attitude towards that belief". Ayer