I plan to explain not only what Logic is, but also unveil its importance and weight within the realm of Christian Apologetics. Along with explaining how the Christian and the atheist account for the existence of logic, I will also spell out what the laws of logic are and how to test the statements in an argument to determine whether it is true or false.

Logic consists of thinking, understanding, and forming perceptions conducted or assessed according to strict principles of validity. While being part science and part art, the goal of logic is to reach the truth by utilizing clear and effective thinking.

According to D.Q. McInerny in his book Being Logical, “logic is the very backbone of a true education, and yet it is seldom taught as such in American Schools. To [his] mind, logic is the missing piece of the American educational system, the subject that informs every other subject from English to history to science and [to] math.” In it’s most basic form, logic is the way that we can find fact, validity and truth.

For the Christian, logic not only comes in handy when trying to ascertain the truth from a specific study, but also in argument with those from others faiths, particularly atheism. Now do keep in mind that when I use the word argument I do not mean quarrel. These two words mean two entirely different things. What I mean by the word follows the definition which is ‘;a set of reasons given with the aim of persuading others that an action or idea is right or wrong.’ In short, arguing has the goal of getting to the truth, whereas quarreling has the goal of getting to the person. Now if we look in Bible in 1 Peter 3:15, we are reminded that when we give a reason for the hope that is within us, we are to do so with gentleness and respect, not with spite and hostility. So therefore it is not a quarrel or a fight we are looking for, but a discussion aimed at guiding our opponent or interlocutor to the truth of Jesus Christ and his sacrifice that he made for us on the cross.

Under the employment of science, philosophy and theology, logic can help you arrive at the proper conclusion that God not just might exist, but that he** must exist! In discussion with unbelievers, logic is one of the key tools that theologians, philosophers, and apologists use to rip their opponent’s arguments apart at the seams.

In trying my best to give a brief but thorough explanation of logic, I plan to cover what is commonly known as the First Principles or Laws of Logic.

First Principles (Laws of Logic)

In order for us to believe that Abraham Lincoln abolished slavery in 1863 by issuing the Emancipation Proclamation it has to first be given as a first principle that Abraham Lincoln even lived. Likewise, in order for Subrahmanyan Chandrasekhar to study the mass at which a star becomes a dense white dwarf instead of a black hole, the first principles of mathematics and the theory of relativity had to be a given.

Much like these examples, Logic also contains its own set of First Principles or Laws. They are the foundation and the root to how we arrive at all knowledge. While the three laws that I am about to introduce may sound very similar, their functions can be drastically different while in a discussion.

The Law of Identity Stated: A thing is what it is and is not what it is not. Example: An apple is an apple. An apple is not a banana, a dog, or a house.

The Law of Excluded Middle Stated: Between being and nonbeing there is no middle state. Example: The light in the house is on or off. There is no other option.

The Law of Non-Contradiction Stated: Something cannot both be and not be at the same time and in the same respect. Example: Two plus two equals four. Two plus two cannot equal four and six.

Following is a basic example that will go through each of the three laws to help tell the difference between them all:

  • (Law #1) I am a human being. I am not a giraffe, a zebra, or a gorilla. But I am a human being.
  • (Law #2) I am a human being. I am not part giraffe, zebra, or gorilla. I am completely a human being.
  • (Law #3) I am a human being. I am not also a giraffe, a zebra, or a gorilla. I am only a human being.

But imagine for example that you are a human being, but you are also part zebra (I said imagine). Then Law #2 would seem to defeat itself right? Wrong. If you are part human and part zebra, it would need to be stated in your argument, otherwise the statement “I am a human being” is false to begin with. In order for your argument to be sound, you would have to state that “I am part human being and part zebra,” and then the rest of argument would shape itself around that.

In argument (remember the definition), we can use these First Principles to decide whether or not the statements or arguments of our fellow interlocutor are true or false. This moves us towards our next topic of reasoning.


Reasoning is the power of the mind to think, understand, and form judgments by the process of  logic. It is how we arrive at what is right, possible, practical, or just plain common sense. Let’s try putting it this way; if First Principles (Laws of Logic) are the road on which we drive, and the truth is our destination, reasoning is the car we use to get there. By playing close attention to the road we are using (i.e., First Principles) we can know whether or not our car will ever reach its destination.

categories: apologetics, basics