After you’ve established your credibility and built a foundation of trust during your speaking presentation, it’s time to move on to the logic of your argument. If you share a core belief with your audience (known as a commonplace or a shared belief), you can start with it and proceed from the general belief to the specific conclusion. This is deductive logic and most logicians consider it the most powerful argumentative form. If you don’t have a shared belief with the audience, however, you’ll need to start with specific cases and proceed to a general conclusion. This is inductive logic. With deductive logic, you start with a shared belief. With inductive logic, you end with a shared belief. Learn more in the video.