his love of truth

Derek Parfit, with an unexpected near-short-story parked right at the top of his acknowledgements in Reasons and Persons:

Seventeen years ago, I drove to Andalusia with Gareth Evans. I hoped to become a philosopher, and as we drove through France I put to him my fledgling ideas. His merciless criticisms made me despair. Before we reached Spain, hope returned. I saw that he was almost as critical of his own ideas. Like many others, I owe much to the intensity of his love of truth, and his extraordinary vitality. I record this debt first because he died when he was 34.