Problem solving is done in two ways. The first is based on expertise or experience on addressing similar issues. The second is to resort to first principles, going back to ask the most fundamental questions regarding the problem on hand. In reality, actual problem solving includes a combination of both, but the balance may differ. Expertise or experienced based problem solving is typically more efficient but could become linear and in-imaginative. First principles problem solving is needed to address ambiguous and fluid issues but could take more time. A good problem solver can master both and knows under what conditions what ought to be the optimal balance between the two approaches ought to be. And, adjust along the way.