Logic in spoken English: Deductive

Are you familiar with logic in English? Using logic well will help you convince people of your opinion and score more highly in speaking tests.  

This is a quick guide to a common type known as deductive logic. That means we start with a major premise, add a minor premise, then draw a logical conclusion based on them. 

Here is perhaps the most famous example: 

Major premise: All humans are mortal.
Minor premise: Socrates is human.
Conclusion: Socrates is mortal.

You can also follow this line of reasoning for many other topics: 

Major premise: Cities with good food are great to live in.
Minor premise: Portland has good food.
Conclusion: Therefore, Portland is a great city to live in. 

It's useful to put aside the message and just think about it like math: A = Band C = A, so C = B.

Put another way:

A) good food = Bgreat cityand

C) Portland = Agood foodso

C) Portland = Bgreat city

This is simple, but a lot of students miss it when they are speaking. For instance: 

My hometown is a great place to live.
There is a lot of really good food there. 

That example is not a finished logical argument. It's missing a step.

Here is that argument, done logically: 

[Claim] My hometown is a great place to live.
 I think (A) good food makes for a (B) great place to live. 
(C) My hometown has a lot of (A) really good food. 
Therefore, (C) my hometown is a (B) great place to live. 

Although that was a logical answer, it's a bit weird in spoken English. It needs detailed evidence. Here's the same logic with some detail, in spoken English. It still sounds a bit weird, but it's an improvement.

I'm from Portland, Oregon. It's a great place. First of all, when I think about places to live, good food is the most important. We eat every day, hopefully three times a day, and we should enjoy that time! Portland has the best food. There are so many great restaurants. The ingredients are local and fresh, and the flavors are a mix of different cultures, like Mexican, Chinese, American, and more. It's all done so well. You have to go and taste it for yourself. So, since good food makes for a good place, and Portland has the best food—obviously, it's a good place to live!  

If you want to convince people of your opinion and get a high score in your next speaking test, then practice making your logic plain and clear.

Try it now. Here's a question to help you start:

What do you recommend visitors eat in your hometown?

Think about what is important for visitors. Think about what makes for good food. Then use deductive reasoning in your answer.


Here is a list of resources to help you communicate logically:

If you have any questions or would like to practice this skill, you can ask your teacher in your next English class.