Article Category: Speechwriting

What is Logos and
Why is it Critical for Speakers?


Have you ever listened to a speaker and thought:

  • “I’m… so… lost.”
  • “How did he come to that conclusion?”
  • “Interesting theory, but it wouldn’t work for me.”
  • “No way! That number has to be wrong.”
  • “Nice slides, but I’ll stick with my own method.”

In all of these cases, the speaker probably suffered from poor logos. As a result, it’s doubtful that you adopted their central message or followed the call-to-action.

In this article of the Ethos, Pathos, and Logos series, we examine logos and the importance of conveying your message in a way that is both understandable and convincing to your audience.

Three Pillars of Public Speaking
  1. Ethos, Pathos, Logos - Introduction
  2. Ethos - Speaker Credibility
  3. Pathos - Emotional Connection
  4. Logos - Logical Argument

What is Logos?

Logos is the Greek root word from which the English logic is derived.

So, it isn’t surprising that, in speaking, logos is often equated with “logical reasoning” or “an argument based on reasoning”.

You might be thinking that logic is dry and boring. You might also be thinking that you want to be a dynamic and fun speaker, and so logical reasoning isn’t really that important to you.

While you may not get turned on by logical analysis, it is critical to your success. Before we can see why logos matters to you as a speaker, however, we need to define a few terms.

A (Very) Brief Tour of Logical Reasoning

Logical reasoning has two flavors:

  1. Deductive reasoning, and
  2. Inductive reasoning

Deductive Reasoning

Deductive reasoning consists of one or more deductive arguments. You generally start with one or more premises, and then derive a conclusion from them. Premises can be facts, claims, evidence, or a previously proven conclusion. The key is that in a deductive argument, if your premises are true, then your conclusion must be true.

For example, consider the following deductive argument:

  1. Audiences hate all boring things. (premise)
  2. Bullet-point slides are boring. (premise)
  3. Therefore, audiences hate bullet-point slides. (conclusion)

So, if audiences hate boring things (yes!) and if bullet-point slides are boring (yes!), then audiences must hate bullet-point slides.

Inductive Reasoning

Inductive reasoning is similar in that it consists of premises which lead to a conclusion. The difference is that the conclusion is not guaranteed to be true — we can only state it with some degree of confidence.

For example, consider the following inductive argument:

  1. All Six Minutes articles you have read in the past were insightful. (premise)
  2. This is a Six Minutes article. (premise)
  3. Therefore, this article is insightful. (conclusion)

Given these premises, it is reasonable to expect that this article will be insightful, but it cannot be stated with certainty based on those premises. It must be inferred.

Audiences and Logical Arguments

Your audience is applying deductive and inductive reasoning all the time.

Okay, so why is this important?  It’s important because your audience is applying deductive and inductive reasoning all the time. It happens subconsciously, but they are doing it before you start speaking, while you speak, and after you’ve finished.

Let’s consider an example.

Example Scenario: You are trying to convince your audience to try a new weight-loss diet.

  • You claim that the new diet reduces hunger. (premise A)
  • You claim that reducing hunger will reduce caloric intake. (premise B)
  • You claim that reducing caloric intake will cause weight loss. (premise C)
  • You conclude that the new diet will cause weight loss.
    (This is a sound, deductive conclusion which must be true if premises A, B, and C are true.)

What could your audience be thinking?

  • Every diet I have tried in the past has failed miserably. (premise D)
  • This new diet is like those failed diets. (premise E)
  • Therefore, this new diet will fail miserably.
    (This is a reasonable inductive conclusion drawn from premises D and E.)

Because their own conclusion is based on strong, emotional experiences (i.e. a failed diet is emotional), it has high pathos and probably trumps your conclusion. Since your audience has to resolve these conflicting conclusions, they will look to your arguments for flaws. Although your deductive conclusion is sound, they will doubt your premises:

  • “I’m always hungry when I am on a diet!” (counters premise A)
  • “But if my caloric intake drops, I won’t have enough energy to exercise, and I’ll gain weight!” (counters premise C)

Your success depends on your ability to simultaneously make your argument stronger and competing arguments weaker.

How can you be persuasive in this challenging scenario? Your success depends on your ability to simultaneously make your argument stronger and competing arguments weaker.

For example:

  • You can boost your argument by providing supporting facts, diet research, or even your personal success story with the new diet.
  • You also must show why this new diet is unlike all those past failed diets. If successful, you would significantly cast doubt on premise E, and their entire inductive argument.

Kill Two Birds with a Single Stone: Commonplaces

It may seem impossible to build a strong argument when you’ve got to compete against a lifetime of beliefs and premises that your audience has previously formed. You may wonder how you can persuade anyone of anything.

The answer: commonplaces.

Commonplaces are simply beliefs which are widely held. Commonplaces often represent “shared wisdom”, and come from many sources. For example:

  • Family members may agree that “eating dinner together every day keeps us strong”.
    • This commonplace would make it hard for you to convince them to join a club that meets in the dinner hour.
  • Organizations may have core values which include “communication is key to our success”.
    • This commonplace means that they are particularly receptive to ideas which promise to improve organizational communication.
  • Society at large generally believes that “freedom of speech is a good thing”.
    • This commonplace would be a good starting point to persuade members of your school board not to ban controversial classics from the school library.

There are two keys to using commonplaces in your speeches:

  1. Commonplaces can be used as (often unstated) premises in your speeches. You can use them just as you would use any other fact or claim.
  2. When your commonplaces are different from your audience’s commonplaces, use theirs, not yours!

A wonderful example of this second principle is provided by Jay Heinrichs in Thank you for Arguing, page 101:

Suppose you want to encourage students graduating from an elite private liberal arts college to enlist in the military. Use the audience’s commonplaces, not the military’s. Instead of “A strong nation is a peaceful nation,” say, “Our armed forces can use independent, critical thinkers.”

When you use your audience’s commonplaces as your premises, your arguments appear much, much stronger. You don’t have to convince them to adopt a completely new viewpoint; rather, you are simply encouraging them to take what they already believe (the commonplace) and apply it to a new scenario.

Okay, I’ll Use Commonplaces. Anything Else?

Unfortunately, there’s more to it than that. Using audience commonplaces is just one particularly strong technique.

In general, you can develop strong logos by following three general principles:

  1. Make it Understandable
    Whatever arguments you employ, they have to be easily understood by the audience before they can be persuasive.
  2. Make it Logical
    Make sure your arguments stand up under the deductive and inductive reasoning that your audience will be using. Make sure your premises don’t have holes in them, and have a strategy for addressing competing arguments which your audience already believes.
  3. Make it Real
    Premises which are based on concrete and specific facts and examples tend to be accepted quicker than premises which are abstract and general. The more easily your premises are accepted, the more easily your conclusions will be as well.
Three Pillars of Public Speaking
  1. Ethos, Pathos, Logos - Introduction
  2. Ethos - Speaker Credibility
  3. Pathos - Emotional Connection
  4. Logos - Logical Argument

Why is Logos Critical for Speakers?

Preconceptions are not easily pushed aside. If your presentation is hard to follow, or if your arguments are fairly weak, your audience will find it easy to dismiss your ideas.

Sound, logical arguments, on the other hand, are hard for your audience to ignore. When combined with good ethos and pathos, strong logos will cause all but the most stubborn audience members to give strong consideration to your ideas.

The Circular Relationship between Logos and Ethos

By demonstrating logos with strong, logical arguments, your audience will tend to see you as knowledgeable and prepared. This, in turn, raises your ethos (because, after all, only someone with pure intentions would work so hard to prepare such a convincing argument).

Similarly, speakers with high ethos tend to receive less opposition when they present logical arguments. Their facts and claims are more easily believed.

Work on both traits, and you will be much more persuasive.

How do you Establish Logos?

There are many specific ways to establish logos throughout your speech, and we’ve hinted at some of them already in this article.  We examine some of these methods in greater detail in the next article of this series.

This is one of many public speaking articles featured on Six Minutes.
Subscribe to Six Minutes for free to receive future articles.