Guide to Critical Thinking

1.3 What Is Logic?
Having dispelled some common misconceptions, we can now occupy ourselves with a funda-
mental question for this book: What is logic? A first attempt to define logic might be to say 
that it is the study of the methods and principles of good reasoning. This definition implies 
that there are certain principles at work in good reasoning and that certain methods have 
been developed to encourage it. It is important to clarify that these principles and methods 
are not a matter of opinion. They apply to someone in your hometown as much as to someone 
in the smallest village on the other side of the world. Furthermore, they are as suitable today 
as they were 200 or 2,000 years ago.
This definition is a good place to start, but it leaves open the questions of what we mean 
by “good reasoning” and what makes some reasoning good relative to others. Although it is 
admittedly difficult to cram answers to all possible questions into a pithy statement, defini-
tions should attempt to be more specific. In this book, we shall employ the following defini-
tion: Logic is the study of arguments that serve as tools for arriving at warranted judgments. 
Notice that this definition states how logic can be of service to you now, in your daily routine, 
and in whatever occupation you hold. To understand how this is the case, let us unpack this 
definition a bit.
The Study of Arguments
This definition of logic does not explain 
that there are principles at work in 
good reasoning or that these princi-
ples are not necessarily informed by 
experience: The meaning of the word 
argument in logic does the job. Argu-
ment has a very technical meaning in 
logic, and for this reason, Chapter 2 is 
dedicated entirely to the definition of 
arguments—what they are, what they 
are not, what they consist of, and what 
makes them good. Later in this chap-
ter, we will survey other meanings for 
the word argument outside of logic.
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