Major definitions of the schema include those of Bartlett, Craik, and Piaget. They focus the schema as a key template for information, but they eschew the Kantian idea of the schema as a key to the structuring of knowledge. Major present-day concepts of the schema are dependent on the "frame." The role of analogy put front and center by Kant is major in the advance of the schema concept to deal with the unknown and to project new ideas. Selz took on the problem of the schema's place and function relative to productive thinking.