Short Little Lessons in Logic: The Science of Logic

Date

July 30, 2018

author

Lesson 1: The Science of Logic

What you’ll learn in this lesson:

How logic forms the basis of correct reasoning

How it is used and what makes it practical

The topic areas of logic

What is logic?

Logic, put simply, is the study of the rules of right reasoning. While the study of formal logic may not be something many people have done, most people use logic every day, many times a day without realizing it. The ‘rules’ of logic were developed from a study of the way the human mind organizes ideas and this study has developed patterns of reasoning that became formalized over time. By studying logic, you can improve the way you organize your thoughts and logic can give you the power to analyze the way others have organized their thoughts so you can determine which ideas are good and which ideas are not so good. This is the first lesson in a series that will teach out how to do just that!

What do you mean by ‘right’ reasoning?

Some people when they read the definition above get a little defensive and ask, "Who is to say what the "right’ rules are? Isn’t logic just something that people created and if so, who is to say what is right and wrong about the way we think?" These are good questions!

Logic attempts to describe when the ideas we have are related to one other in a way that makes sense or are reasonable. Most of us have talked to someone or listened to a politician or philosopher who tried to get us to believe something new. At the end of their speech, we might scratch our heads and wonder how and if the idea they want us to believe relates to the ideas they used to convince us. "That doesn’t follow!" you might say in response. What you’ve figured out is that the person isn’t reasoning properly. Here’s an example:

Suppose a person tries to convince you that the earth is flat. He might give you the following argument:

If I look out across a large, flat surface of land or water and it appears flat, then the earth is flat
I’m looking across the Pacific Ocean to the horizon and it appears flat
Therefore the earth is flat!

The third sentence (called the conclusion — something we’ll talk about in future lessons) doesn’t seem to follow from the evidence given in the first two sentences. In fact one of the sentences is false and so attempting to draw the conclusion, sentence 3, from sentences 1 and 2 just doesn’t work. Here’s another example:

Suppose a friend wants to convince you to go to college because you can make better money if you do. In order to convince you, she presents the following argument:

If a person goes to college, then she will make good money
Maria is making good money
Therefore, Maria must have gone to college

This sounds pretty convincing, right? You might even agree that all the sentences are true. But if you look more closely, perhaps you can see that something has gone wrong. Even if we agree that sentences 1, 2, and 3 are true (let’s assume they are for now), it doesn’t seem we can get to the conclusion from the reasons cited in the first two sentences. Couldn’t it be true that a person can make good money without going to college? All the first sentence tells us is that college is one way to make good money. It doesn’t tells us that going to college is the only way to do it. But that’s what this person is claiming in the second and third sentences. So the relationship between the first sentence and the two that follow aren’t correct. Something has gone wrong.

Don’t worry if you didn’t follow all that. We’ll look more closely at what is going on and how you can learn to analyze arguments like these in later lessons. For now, I’m only trying to illustrate what we mean by ‘right’ vs. ‘wrong’ or ‘correct’ vs. ‘incorrect’ reasoning. Just as mathematics provides us with the rules for properly relating numbers (3 + 5 = 8 is ‘right’ and 3 + 5 = 77 is ‘wrong’) logic helps us figure out when ideas are in the right relationship to one another. This also helps us see how logic was more discovered than invented. The idea is that the human mind works in a specific way to organize ideas and logic is the discovery that un-covered that organization.

Other areas of logic

So logic is the science that analyzes how ideas relate to one another and, as we mentioned, this analysis is typically done on what are called arguments (this is a formal term used in logic and we’ll look at how these are constructed in an upcoming lesson). But logic studies other things as well and we’ll take a look at each of these in turn. For now, here is a list of the things you’ll learn how to analyze as you learn to use the tools of logic:

Logic studies the rules for correct reasoning—something we looked at above. While the rules are important, they’re only a part of what is involved in analyzing arguments.
Logic also looks at forms of improper reasoning called ‘fallacies.’
Finally, logic studies what are called ‘truth values.’ The rules provide us with the form an argument should take—the relationship. Truth value is the study of whether the ideas actually are true or not.

These are just some of the things you will learn about in a formal study of logic. The discipline is vast and this series will cover the basics. If you take a college-level course, you can go even deeper into the study and learn much more. The foundation you’ll get in this series will give you enough tools so you can analyze and construct your own arguments.