Where grammar is the input and base knowledge of who, what, where, when, and logic is the processing and understanding developed to arrive at why, rhetoric is the output and wisdom of out actions: the how.
Rhetoric is the art of communication. It is the culmination of the arts of inventing and combining symbols and the art of thinking. You communicate about the things perceived, what they mean, and why they are important (or not).
Logic is the art of arts, but rhetoric is the master art to effectively communicate with foundation of grammar and higher order thinking of logic.
Ultimately, this is what it's all about. Communication about what is in existence. Reality. Truth.
You can also communicate about ideas, imagination, things that might be, are things that are just pure fantasy and don't actually exist and never will.
And you can also take the dark path and use your communication skills to manipulate, deceive and convince people of unreal things. People can live in an unreality that they think is real. They can live in falsehood and think it's truth.
This is where rhetoric is a negative manifestation that has been riled against by philosophers of ancient times. When you just want to win in an argument, you employ rhetoric to merely convince someone with cunning linguistic arts. Sophistry is what is was referred to as.
You may know its false, or not, but you just want get people to buy waht you're selling regardless of whether its true or not.
