Grammar provides the Who, What, Where and When of a topic or subject. Grammar is the learning of terms and definitions or facts, and how a thing is organized. What needs to be learned first, second, etc. It provides the primary or first-order knowledge of a subject. This stage is dominated by the 5 senses and memorization. It provides the answer to, How to Observe.
Logic provides the answer to Why. It is understanding the truths vs fallacies of a subject. It is the practice of non-contradictory thinking. This is the time when one must take in all the information that has been learned and make it their own. The content of a subject learned in the Grammar Stage must taken as pieces and reconstructed into the whole of the subject. Only then will the subject matter be understood. Learning to understand failure is a major step in this phase. Failure is not personal, it provides the knowledge that something was false.
The art of communication. To know and understand something is very different than being able to deliver the idea to someone else. Understanding something so well and having the ability to break it into pieces and present it to others is the goal of this phase. Rhetoric proves the mastery of the first two stages.