Logic Miniseries: Part 1 – The Laws of Logic

Have you ever defended your faith?  If not faith, a controversial topic (e.g. gun laws, abortion, death penalty, etc.)?  More than likely, you have (at least I hope you have at this point in your life).  However, do you think you provided a cogent (clear, logical) and persuasive argument?  Were you ever able to convince someone of your argument and convert them (so to speak) to your view?  Chances are, probably not.  Why?  Because many of us cannot provide a sound, logical argument.  If we knew how fallacious most of our arguments are, our jaws would drop to the floor.  However, fear not! I’m going to help you recognize the common fallacies unbelievers make in day-to-day debate and conversation when it comes to defending our Hope.  Stay with me, though!  Many people see logic, and hightail it in the other direction.  I will make it as painless as possible.  To do so, I’m going to use real world examples from unbelievers like this one:

“You Christians are absolutely nuts; nay, delusional and uneducated, and therefore cannotsocial-1206614_640 be trusted.  The Bible is so dishonest; how can you believe that nonsense?  Everyone knows that science and God cannot coexist.  You either believe in God or you believe in science, it’s that simple!  You Christians deny evolution, but I can see evolution happening every day.  Additionally, evolution is true because science says it’s true.  The only reason you even believe in God is because you were born into a Christian family.  How can you possibly believe something written thousands of years ago written by seemingly primitive people who had little to no clue what science was?  Lastly, the vast majority of scientists don’t even believe God, god, or gods exist.”

If you’ve been a follower of Christ for a while (or maybe even a newer follower), you’ve more than likely come across dialogue such as this.  Can you pick out the logical fallacies?  No?  Don’t worry!  All it takes is a little bit of patience and practice, and you’ll be fine.  This is the first part of the logic miniseries.  I’m not exactly sure yet how many parts there will be (I’ll have to go back and edit at the conclusion of the miniseries), however, I’ll be sure not to overwhelm you with too much information at one time.

idea-1026394_640So, what exactly is logic?  Simply put, logic is a proper or reasonable (or rational) way of thinking about or understanding something.1  There are two types of logic; informal and formal.  Informal logic (also known as every day or ordinary language logic) is an attempt to develop a logic that can assess and analyze the arguments that occur in natural language discourse.2  Formal logic is the abstract study of propositions, statements, or assertively used sentences and deductive arguments.3  If you’re ready to click to another page or throw something out the window at this point, please don’t.  I’ll cover informal and formal logic in later posts.  Now that you’ve (hopefully) taken a deep breath, let’s take the first baby step toward the laws of logic.

The laws of logic govern both reality and thought.  One must presuppose the laws of logic to even make sense of them.  This is something that can only be accounted for with the biblical God.  Why?  Because God is logical (as I will demonstrate shortly), which has been revealed to us as part of His nature.  We were all created in God’s image (Gen 1:27), therefore it is reasonable to assume that we have some of His attributes; thus, it’s no surprise that we’re able to reason logically.  There are three fundamental laws of logic that help us make sense of reality:  the law of identity, the law of noncontradiction, and the law of excluded middle.

Law of Identity – P is P

Simply put, if any statement is true, then it is true.  For example, if it is snowing outside and I say, “it’s snowing outside;” then the statement is true.  In other words, P is the same as itself and different from everything else.  Thus, everything is itself and not something else.

Here’s an example of the law of identity from Matthew 22:21:  “Render therefore unto Caesar the things which are Caesar’s and unto God the things that are God’s.” In other words, God is God and Caesar is Caesar.

Law of Noncontradiction – P is not both P and non-Prubiks-cube-311595_640

Simply stated, a statement cannot be both true and false at the same time.  For example, if I’m holding an apple, I cannot drop and not drop the same apple in the same instance.

Here are some examples of the law of noncontradiction in scripture:

1 John 2:21:  “I have not written to you because you do not know the truth, but because you do know it, and because no lie is of the truth.”

2 Timothy 2:13:  “If we are faithless, He remains faithful, for He cannot deny Himself.”

Titus 1:2:  “…in the hope of eternal life, which God, who cannot lie, promised long ages ago,…”

Law of Excluded Middle – Either P or non-P

Either something is true or false, there’s no other option.  For example, if I were to say, “it is snowing;” it is either snowing, or it is not.

Here are some examples of the law of excluded middle from scripture:

Matthew 24:35:  “Heaven and earth will pass away, but my words will not pass away.”

Matthew 12:30:  “Whoever is not with me is against me, and whoever does not gather with me scatters.”

Now that the appropriate logistical foundation has been established, can you think of other scripture (not addressed in the aforementioned examples) that fit into one of the laws of logic?  If so, which ones?

Does it make a little more sense now on how we’re able to reason?  It may seem so obvious and a bit silly, however, we often take logic for granted (among other things).  While reading through scripture, pay attention to Jesus’ dialogue with the Pharisees and even when He was tempted by Satan.  He reasons with them perfectly!  Moreover, pay close attention to Paul in his letters to the churches and how he’s able to reason with them.  It’s quite amazing (as only our Lord knows how to be!).

As we move forward, you will slowly but surely begin to discern flaws in arguments from unbelievers in their attempt to defend their worldview.  Remember though, with any/every encounter we have as believers, we must converse with gentleness and respect (1 Peter 3:15).



1  http://www.merriam-webster.com/dictionary/logic

2  http://plato.stanford.edu/entries/logic-informal/

3  http://www.britannica.com/topic/formal-logic

Other Sources:

Wallace. J.W. (2013). Is God Real? Evidence from the Laws of Logic. Retrieved from http://coldcasechristianity.com/2014/is-god-real-evidence-from-the-laws-of-logic/

Encyclopedia Britannica. (2015). Laws of thought. Retrieved from http://www.britannica.com/EBchecked/topic/593494/laws-of-thought

Johnson, P. (1995). The Law of Contradiction. Retrieved from http://www.spurgeon.org/~phil/articles/lawofcon.htm

Moreland, J.P. (2015).  What are the Three Laws of Logic? Retrieved from https://arcapologetics.org/objections/three-laws-logic/


Author:  Brian Kurkjian, Ed.D




4 thoughts on “Logic Miniseries: Part 1 – The Laws of Logic

  1. Like your approach. Don’t worry about acceptance you are on the correct track..
    All logic must maintain a balance…. Pro11:1; John 8:32.. I find the logic of math or analysis is similar to the logic of scripture, both with the same creator. I believe this what some of the great mathematicians/scientists/philosophers were telling us.

    Keep up the good work


    • I appreciate your kind words and glad you enjoyed the post. By the Grace of God I hope to continue this much needed topic as long as I am able 🙂


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