When you take a long view, you see that innovations seem to appear at moments in history when the conditions are most conducive. The conditions are a need in the social community, and the existence of a suitable technology base. The innovation begins when someone proposes a new combination of existing technologies and components to meet the need. Timing is delicate and critical. Once the conditions are "ripe," several people may propose the same innovation around the same time. Many innovation proposals fail because of poor timing: there is too little interest in the social community or the technologies needed to make them work do not exist.