Peter Singer, often called the world's most influential philosopher, is turning 80, and he's returned home to Melbourne too, after almost 25 years as a professor of bioethics at Princeton University.
Singer's practical ethics has had a huge impact and caused controversy across issues as diverse as the rights of animals, voluntary euthanasia and abortion, freedom of speech, and our moral obligation to help those living in extreme poverty.
Given all that's happened in Singer's world and in the wider world, it seemed like a good time to ask him to reflect on his life and work, and about the issues of today, from Trump to anti-Semitism and the limits of free speech.
Today's conversation is hosted by Good Weekend senior writer Gay Alcorn.