We live in two worlds. The first and most obvious is the public world we all know. It contains the earth with its objects and animals, and the atmosphere and the heavens. We can generally agree on the things in it. In recent centuries a public science of this world has grown up. Anyone can make an observation, perform an experiment, set out a chain of reasoning, and publish the finding for others to examine or challenge. Many events in the physical world are repeatable and publishable; even those which are essentially unpredictable (e.g. nuclear decay in a radioactive atom) often obey publishable statistical laws. Such publications are typically made by specialized scientists, and few people deny the scientific view of the physical world that they have built up.