Which principle emphasizes moving from simple ideas to complex ones?

Concept: Teaching is governed by a set of general principles, and each one controls a different dimension of classroom work: one controls the learner's drive, one controls the learner's participation, one controls retention over time, and one controls the order in which subject matter is presented. The principle that controls order requires the content to be graded — instruction begins with what is easy and already familiar and advances in small steps to what is harder and unfamiliar, so that no single step demands a jump the learner is not prepared for.

Application: The question asks for the principle that governs moving from simple ideas to complex ones. That is a statement about the order in which content is arranged — not about the learner’s drive, participation, or retention. The principle of progression is defined by exactly this graded ordering of subject matter, so it is the principle the question describes.

Contrast with the other principles named:

• Principle of motivation — arousing and sustaining the learner's interest and willingness to learn; it acts on the learner's drive and applies whatever order the content is in.

• Principle of revision — returning at intervals to material already taught so that it is retained; it acts on retention after teaching, not on the ordering of fresh content.

• Principle of activity — learning by doing, keeping the learner mentally and physically engaged; it acts on the learner's mode of participation, not on the ordering of content.

• Principle of progression — grading content by difficulty so that each step builds on the previous one; of the four, this is the only one that is about sequence.

Result: The principle that emphasizes moving from simple ideas to complex ones is the principle of progression, commonly stated as the teaching maxim “from simple to complex”.