The unrivaled bestseller in the field of logic and argumentation
Required Reading for the Law Aptitude Test (LEET) and the Public Service Aptitude Test (PSAT)
A comprehensively revised and expanded edition commemorating the 20th anniversary has been published!

The easiest and most accurate explanation of logic, "Logic is My Power," which has been an unrivaled bestseller for 20 years, has returned with a new look.
This book is a must-read for students preparing for the Law Aptitude Test (LEET) and the Public Service Aptitude Test (PSAT), and serves as another textbook for high school students preparing for essay tests and college students who want to develop their logical thinking skills. As a logic textbook that has been loved by countless readers for the past 20 years, it contains even more abundant examples and explanations.


Even though times have changed, the need for logical thinking remains.
No, it became more urgent.
In modern society, where countless values ​​and perspectives coexist, and with the advancement of technology, communication has become much easier, but proper communication is actually becoming more difficult.
As we become accustomed to the convenience of algorithms, it becomes easier to become trapped in a narrow perspective.
In these chaotic times, the power of logic is necessary to maintain direction, maintain one's own thoughts, and effectively listen to and communicate with others.


"Logic is My Power" emphasizes "practical" logic that can be applied directly in real life.
Therefore, in this comprehensively revised and expanded edition, various examples in the book have been revised and supplemented to suit modern times.
It is particularly noteworthy that the number of logic practice problems has increased significantly.
Because logical thinking is a skill rather than knowledge, it cannot be limited to simply learning the concepts and methods of logic.
We need to see many good examples of logical thinking and practice and put it into practice sufficiently.
Accordingly, the amount of practice problems has been greatly increased.
As you read the book and practice one by one, you will find that your logical power will grow significantly.

To summarize, logical thinking begins with finding and asking the reasons for a certain claim.
If you don't just say "that's it" and just give a reason or basis for something, you are already thinking logically.
But if we're going to do it, we should think more logically.
To do so, you must base your argument on appropriate reasons, not on emotions or reasons that are contrary to the facts.
So what exactly is a good reason? That's what this book is about.

--- p.26

To think logically, you must have an open mind and a critical attitude.
Ultimately, thinking logically is first a matter of our attitude and posture, and the ability and skills to think logically are secondary issues.
So, if you want to become a logical person right now, listen carefully to what the other person is saying.

--- p.34

Argumentation is not a destructive task of overthrowing the opponent, but a constructive task of working together to find the best conclusion.
Of course, you should not view your opponent in the debate as someone to be subdued, but as a partner.
To do that, you must first provide the other party with sufficient information and allow them to make decisions freely.
Since the purpose of argument is not to win but to find the best solution, deliberately hiding information that is advantageous to the other party is fatal and ultimately unhelpful to me.

--- p.68

Applying the principle of compassionate interpretation when making arguments does not mean you have to be a good person.
This is for the practical purpose of saving unnecessary time.
Even if we interpret Hyung-seok's argument as the first one, if Hyung-seok were a rational person, he would immediately respond that that was not his original intention.
If you were merciful from the beginning, this process would not have been necessary.

--- p.72

The new logic emerged from the question of how to develop the ability to think logically and critically in everyday life.
Therefore, studying informal logic means practicing how to think logically.
This book aims to introduce the practice method and content and to help with practice.
Rather than taking on the role of an exercise physiology professor studying the physical changes of runners, you take on the role of a trainer who trains runners.

--- p.84

For anyone who wants to think rationally and logically, it is really important to examine whether those abstractions are truly relevant to the topic being discussed.
In particular, the abstractions that a person has—such as being from a certain region, Korean, or female—are not abstractions that he or she has chosen through his or her own efforts, so judging others, whether positively or negatively, based on such abstractions is not only illogical but also unethical.

--- p.117

In fact, much of the ability to think logically, including finding premises and conclusions, often depends on knowledge or interest in the field rather than solely on analytical and logical abilities.
If you feel you lack logical thinking skills, it's often because you don't have the specialized knowledge necessary to solve problems, or because the problems are too abstract or outside your interests to properly grasp them.

--- p.176

However, in order to evaluate an argument, you must have a clear understanding of what the argument is trying to claim and what basis it provides for that claim.
It would be absurd to accept or reject the other person's argument without fully understanding it.
[Omitted] The primary goal of argument analysis is understanding, not refutation.
First, you need to find out what conclusion the person making the argument is trying to argue, and then you need to find the premises presented to support that conclusion to make the other person's argument as reasonable as possible.

--- pp.215-216

Evaluating an argument means checking whether the premises of the other party's argument can be accepted and whether the relationship between the premises and the conclusion is correct. However, many people evaluate the conclusion right away when evaluating an argument.
As I just said, whether or not you accept the conclusion itself is not the criterion for evaluating an argument.
Yet, when people hear an argument they don't agree with, they simply disagree without examining the basis for the argument or the relationship between the basis and the argument.
Likewise, you simply agree with any argument you agree with.

--- p.248

He said that the reason we argue is to try to convince others of a somewhat surprising conclusion that they do not take for granted, based on assumptions that are taken for granted.
Soon, the premise must be more certain than the conclusion.
This way, the listener can rationally accept the conclusion from the premises.

--- p.289

What on earth does the age of the person making the argument, where they're from, or what school they graduated from have to do with whether their argument is right or wrong? Yet, in our country, when an argument gets stuck, people blurt out, "How old are you?" or "You went to a crappy school..."

--- pp.335-336

We believe that the critic's moral standing and past conduct are relevant to the content of our criticism, and so we attack each other in that way.
However, logic textbooks teach that in this case, one commits the fallacy of the long-wave fallacy.
So, when we criticize, can we never bring up the other person's moral standing or past actions? And if so, in what cases?

--- pp.340-341