Scientists themselves are of surprisingly little help. They find it difficult to talk of what they do because they tend to assume detailed knowledge is required for generalities to be understood. They find it hard to grasp the concept of the meaning of their work, assuming this to be a debate that takes place at a lower level than the specialized discussions with their colleagues. When they do generalize, - or "popularize" as it is usually called with a noticeable degree of contempt - they tend to reveal a startling philosophical naiveté.