How to Build a Strong Argument, Part 2: Deductive Reasoning

If you are wondering how to get your foot in the door with potential clients or build agreement with your audience, deductive reasoning might be the tool you are looking for. We are in part 2 of a 3-part series on argumentation. On Monday, we examined Stephan Toulmin’s model of argument. Today, we’ll look at deductive reasoning, another method you can use to construct your case. Again, when we talk about argument, we simply mean the way we organize our thoughts to produce an effective message.

Deductive reasoning moves from large, general principles to smaller, specific cases. The scientific method makes use of deductive reasoning when it starts with a hypothesis that it seeks to test. Deduction is what I call a “funnel” argument. If we can get the audience to agree to a widely accepted principle, we have entered the funnel. We can then continue to narrow the argument, following patterns of observation, until we’ve reached our conclusion. Perhaps the most widely recognized form of deductive reasoning is found in the popular syllogism:

Premise: All men are mortal,
Premise: Socrates is a man,
Conclusion: Therefore, Socrates is mortal.

Lecturer and writer, Austin Cline explains further, “As you can see, if the premises are true (and they are), then it simply isn’t possible for the conclusion to be false. If you have a correctly formulated deductive argument and you accept the truth of the premises, then you must also accept the truth of the conclusion.”

Looking at the example above, you can see how starting with a generally accepted principle moves the audience into the funnel. In your own speaking, begin by using an appealing premise. Something like, “Everyone likes to get something for free, right?” or “We all want to invest our time and energy into something worthwhile.” When you begin with a general premise, you invite the audience on board. Then, work to progressively show how your ideas align with or further illustrate this premise.

Deductive reasoning also helps to establish what researchers call a “triple nod” or a “yes set.” For example, if a salesperson sees you wearing a particular team’s jersey and asks if you root for that team, you’ll probably say yes. She might follow that question up with a statement like “it sure is fun to root your team on, huh?” You’ll probably answer yes or at least nod in agreement with this second question. The salesperson then has you in the funnel for the third question, “Can you spare 2 minutes for me to show you a new product that I think will interest you?” Because you’ve already answered “yes” twice, you are much more likely to answer “yes” to the third question. While this example isn’t a deductive argument, it can show how a pattern of agreement, like the one build in deduction, can produce desirable outcomes. Outcomes like getting your audience to interact, connect, or even agree with you.

On Friday, we’ll post part 3 of our series on developing strong arguments where we’ll look at inductive reasoning. In the meantime, check out Presentation Mentor’s online presentation skills course. Why should you?

Premise: We all need skills to get better at communicating.
Premise: Presentation Mentor’s course teaches proven skills.
Conclusion: Presentation Mentor can help you get better at communicating.

The post How to Build a Strong Argument, Part 2: Deductive Reasoning appeared first on Presentation Mentor.

Older Post
Newer Post
Close (esc)


Looking for a presentation coach? Our Founder and CEO, Scott Schwertly, is currently offering 60 minute online consultations ($250/hr) via Skype where we can discuss the best ways to woo your audiences and wow your listeners. Sign up today!

Schedule an Appointment

Age verification

By clicking enter you are verifying that you are old enough to consume alcohol.


Shopping Cart

Your cart is currently empty.
Shop now