When you recall three instances of patent boutiques failing to handle litigation as well as do general litigation firms, inductive reasoning lets you conclude to use generalist litigation firms. When you know already that Ivy League graduates who clerked for the Supreme Court are smart, you use deductive reasoning when you hire one quickly. These forms of reasoning are common and commonly understood.
Less commonly, creative lawyers rely on a third type of reasoning: abductive reasoning, the logic of what might be. According to Fast Company, Oct. 2006 at 56, this is a form of intuitive, whole-brain creativity (See my post of Oct. 29, 2006 on ambivalency’s boost to creativity.).