The difference between the cook and the chef. While these verbs are often used interchangeably, there is an important nuance. The chef is a trailblazer, the person who invents recipes, he knows the raw ingredients and how to combine them. The cook, who reasons by analogy, uses a recipe, he creates something, perhaps with slight variations, that’s already been created. The difference between reasoning by first principles and reasoning by analogy is like the difference between being a chef and being a cook. If the cook lost the recipe, he’d be screwed. The chef, on the other hand, understands the flavour profiles and combinations at such a fundamental levels that he doesn’t even use a recipe. He has real knowledge as opposed to know-how.