Let me begin this discussion by pointing out that good writing doesn’t simply depend on the richness and persuasiveness of ideas nor on grammatical correctness, but also on our skill in setting thoughts in parallel. By parallel, of course, I mean the clear and orderly positioning of identical syntactical elements in a sentence. Indeed, the basic principle for parallelism is that to ensure clarity and avoid needless distraction, all grammatical elements of the ideas set in a series in a sentence or statement should have the same form and structure.