Logic: What Is It?

Christianity is not primarily an experiential religion but a propositional religion. Don’t get me wrong; it does involve experience. But it is founded on propositional truth. God is a Trinity. Jesus is Lord. Christ was raised from the dead. God saves by grace. Christ is coming back. All these propositions (and many more!) show how much our faith is founded on whether certain claims are true in reality. With all this in mind we are ready to ask, “What is logic?”

Zach Lee, Logic for Christians, kindle loc. 101

Logic is about argumentation. It is about saying something true and then using reasons to prove that it is true.

Zach Lee, Logic for Christians, kindle loc. 124

Logic is based on “logical axioms”, which are foundational and necessary, without which we cannot build any propositional truth. These must be true in order for us to make sense of any reasoning. Knowing these are important for Christians and God-honoring propositions since God cannot contradict Himself. Here are the Laws of Logic:

• Logical Absolutes 1. The Law of Identity
  • A is A – Whatever is, is. Whatever is not, is not. (Lee, 20)
  • Something that exists has a specific nature. A human being is human being and not a rock.
• Logical Absolutes 2. Law of Non-Contradiction
  • A cannot be non-A at the same time. Something cannot both be and not be at the same time in the same way. (Lee, 20)
  • “I am here speaking to you at this moment” and “I am not here speaking to you at this moment” cannot both be true at the same.
• Logical Absolutes 3. The Law of Excluded Middle
  • Either A is true or ~A is true, both cannot be true which would violate Law #2 (law of non-contradiction)
  • Everything must either be or not be. (Lee, 20)
  • “Socrates is mortal or Socrates is not mortal”
  • One of these propositions are true but not both.
  • “Socrates is mortal” is either true or false.
  • “God exists” is either true or false.

According to Tony Costa, Logical Absolutes Logical Absolutes are absolutely true, not subjectively true depending on preference or situation. Otherwise, they would not be absolute. If logical absolutes are not absolute, then no rational discourse can occur since one can argue irrationally and violate the laws of logic.

• Logical Absolutes are Transcendent. Logical Absolutes are not dependent on space. They do not stop being true dependent on location.
• Logical absolutes are not dependent on time. They are universal and unchanging. They do not stop being true dependent on time. They were true 5000 years ago and will be true 5000 years from now. If they are not true then, they cannot be true now.
• Logical Absolutes Logical absolutes are not dependent on people, they are not the product of human thinking. They are not made from human convention. They are discovered not invented or created. People’s minds are different. What one person considers to be absolute may not be what another considers to be absolute. People often contradict each other. Therefore, logical absolutes cannot be the product of human, contradictory minds.
• Logical laws do not cease to exist when people die. They are eternal. Logical absolutes are not dependent on the material world. They are not contingent.
• Logical absolutes are not found in atoms, motion, heat, under rocks, etc. Logical absolutes cannot be photographed, observed, frozen, weighed, or measured. They are not subject to the scientific method. Logical absolutes have no physical properties.

These are true whether you believe them or not. You can believe something to be true but not necessarily be true. Beliefs change, truth does not change, it is immutable.

They exist in the mind.

No one can logically say that they do not believe in the absolute truth or even the laws of logic. According to Zach Lee, “If you really didn’t believe in absolute truth, you surely could not make a case for it. As soon as you use any words, arguments, or sentences, you are showing that you implicitly believe in absolute truth.” (Kindle loc. 212)

The Ultimate Source of Logical Absolutes

Logical absolutes do not have material qualities, they are not dependent on time, space, or matter, including people, they are not subjective.

This law is founded upon Him who says “I AM” (Exodus 3:14). The law of identity in speech. The very source of identity is God Himself, the Great I AM, which literally means, “He who is.”

Without God, there can be no being. Because God is being.

Since they existed before human minds, they must find their source in an Infinite Mind → the Triune God. Since they are unchanging, immaterial, and eternal, they are founded upon the Truth, which is Jesus Christ Himself, who is the same yesterday, today, and forever.

Logical absolutes and truths exist because God exists. All truth is God’s truth because it is part of God’s very nature. Logic is God’s attribute.

Rationality cannot be derived from the irrational.

To God be the glory!

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These are based on our notes on the Logic class by Dr. Tony Costa.

Reference: Lee, Z. (2021). Logic for Christians: critical thinking for the people of God. Lucid Books.

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