I thank you very much indeed for the compliment you are paying me in inviting me to give the James Scott Lecture. It is always an honour to be asked to give a lecture which is, as the nursery-man would say, a “named variety”, and in addition I welcome this invitation from a Society of which I am proud to be an Honorary Fellow.

Your lecturer is invited to talk about “fundamental concepts of Natural Philosophy” and I confess that this set me quite a task. It is one thing to talk about some special branch of research in which one is interested; it is quite another to review in a broad way some general feature of science. It asks for a philosophical approach, and I am not only a poor philosopher but also in a country where philosophy seems to flourish on the native soil. I hope therefore that you will receive what I have to say indulgently.