50 Teaching Minds know where to look to find a faulty part. Experts also know that an engine is misfiring in the first place. What causes what is the real issue in the comprehension of any given domain. We learn to do diagnosis, and to understand what causes what, consciously. This is knowledge that can be taught to us by experts, but it needs to be taught as part of the process of diagnosis. If you have a goal (understanding what is broken or has gone awry is a very typical goal), then it is much easier to acquire information that helps in the pursuit of that goal than it is to acquire that same information with- out that goal. To learn diagnosis, one must practice more and more complex cases in one area of knowledge. 2. Planning: Learning to plan; needs analysis; conscious and subconscious understanding of what goals are satisfied by what plans; use of conscious case- based planning People plan constantly. Often their plans aren’t very complicated. Let’s have lunch is a plan, after all. Sometimes they make much more complex plans. A football coach makes plans to fool the defense. They are called plays. A general makes battlefield plans. A businessperson writes business plans. An architect draws up architectural plans. All these more complex plans have a lot in common with the let’s have lunch plan. Namely, they have been used before or something quite similar has been used before. People rarely make plans from scratch. When they do, they find the process very difficult and often make many errors. Learning to plan, therefore, has two components: being able to create a plan from scratch (which almost never actually happens) and being able to modify an existing plan for new purposes. The first one is important to learn how to do, but it is the latter ability that makes one proficient at planning. Planning from first principles is actually quite difficult. Normally people just modify an old plan. Last week we had steak; this week let’s try lamb chops. This doesn’t