“Ideas are constantly being generated, abandoned, and rediscovered. A good idea—a real breakthrough—will often go unnoticed at the time and may only later be understood as having provided the basis for a substantial advance in AI, perhaps when someone reinvents it at a more convenient time. Ideas are tried out, initially on simple problems to show that the basic intuitions are correct and then on harder problems to see how well they scale up. Often, an idea will fail by itself to provide a substantial improvement in capabilities, and it has to wait for another idea to come along so that the combination of the two can demonstrate value.”