Notes on the first of Five Canons of Rhetoric: Inventio
Inventio is roughly translated into "invention." That is, the foundation of rhetoric is in the creativity of the argument that is presented in a speech. Some people have a natural ability for creating moving speeches. For the rest of us, there is hope. Inventio is a skill that can be developed with practice and awareness.
A speaker can develop the technical skill: that means that the speaker builds her arguments upon the foundation of already accepted ideas. These accepted ideas are drawn from law, primary sources, eye witness accounts, etc.
A speaker can also develop artistic skill: that means that the speaker builds his own argument upon the foundation of reason or emotion.
Whenever the speaker builds an argument, the foundation is critical. The technical foundation requires research to find facts and already accepted beliefs. The speaker then argues passionately for the audience to heed what is factual. This speaker is well read in the content of the speech.
These skills are developed by learning to appeal to reason and emotion.
To appeal to emotion, the speaker must convince the audience that she is trustworthy. This most often comes from identifying with the audience's needs. Once connected to the audience, the speaker offers solutions to satisfy the needs of the audience.
To appeal to reason is a little more complex. The speaker can use either deductive reasoning or inductive reasoning. These are explained below.
Deductive reasoning is used when the speaker starts with some single premise or statement. He then builds his argument on that statement.
Inductive reasoning is used when the speaker starts with a series of ideas or facts and draws a conclusion from those ideas.
