2. Have you ever listened to a speaker or read
something and thought…
3.
4.
5. • Premise 1: All the articles I have read in The New York Times have been
informative.
• Premise 2: I am currently reading an article in The New York Times.
• Conclusion: Therefore, this article will be informative.
Inductive Reasoning
6. • Premise 1: All men are mortal.
• Premise 2: Jack is a man.
• Conclusion: Jack is mortal.
Deductive Reasoning
7. Chef Ming Tsai claims:
• Premise 1: It cuts like a razor.
• Premise 2: The food slides right off.
• Premise 3: It will save you money.
Conclusion: Because it cuts like a razor, the food slides off and you will
save money, you need to purchase this knife.
Aero Knife
8. • Premise 1: Every one of these tools I’ve bought from an infomercial has
not lived up to its hype.
• Premise 2: This product is just like the others I have purchased.
• Conclusion: This product will not live up to its hype either.
HOWEVER…
“I’m… so… lost.”
“How did he come to that conclusion?”
“Interesting theory, but it wouldn’t work for or apply to me.”
“No way! That statistics has to be wrong.”
“Nice presentation, but I’ll stick with my own method.”
Then, in each case, you were questioning the “Logos” portion of the rhetorical triangle. As you can see from this illustration, logos includes the hard data used in crafting any cogent argument. We will speak more about the “ethos” and “pathos” portion of this triangle in the weeks to come.
The word logos is Greek, and if forms the basis of the English word “logic.” So it isn’t a stretch to think of logos as the logical reasoning upon which you build an argument. You don’t want to fall into the potential problems associated with logical fallacies, which you studied in Week 1.
There are two branches of logical reasoning: Inductive and deductive. Using inductive reasoning, one uses premises, or statements that are accepted as true, to lead to a conclusion, but the conclusion may or MAY NOT be true. 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.
So, then, what is deductive reasoning? In a deductive argument, one begins with premises that IF TRUE, must yield a true conclusion. You can easily see how this differs from inference. Additionally, deductive reasoning moves from a general statement to a specific statement. Inductive reasoning does just the opposite.
Let’s see how deductive reasoning is used in this infomercial: http://www.youtube.com/watch?v=dkp7NzFy8EQ
What am I thinking while I watch this? This is a reasonable INDUCTIVE conclusion. Because this conclusion is one based upon high pathos, or emotion, it will probably trump the sales pitch, and I will not purchase the knife. So, you can see that you must consider your audience in building your arguments. How are they likely to respond? How can you refute them with strong logos-based evidence?
And just to look back, logos includes the arguments, benefits, facts, figures, data, statistics, scientific findings, etc. that support your argument.
So you can see that logos is an important part of persuasive argument, but makes up only 1/3 of the rhetorical triangle. Stay tuned for next week’s discussion of ethos.