We've all heard the charge that the Bible is full of contradictions. It seems easy to level the charge of "contradiction" at a passage or two that seem to be talking about the same thing, but don't match. However, a contradiction is a very specific thing, and many times people just don't understand what must happen in order for one statement to be considered a contradiction to another. Simply put, a contradiction means that someone is making a nonsense claim. They are saying something that cannot possibly be true. If a statement does have the ability to be true given additional information, then the statement isn't really a contradiction.
This may seem a little confusing, but let me clarify what I mean. Luckily this area has been very well travelled in the study of logic, so we have a solid foundation from where we can base our definition. The Law of Non-Contradiction is one of the Three Standard Laws of Thought that Professor Ed L. Miller notes that all rational thinking has at its basis. 1 These laws are so simple that they will seem self-evident, even to anyone who hasn't studies critical thinking or philosophy. In fact, Miller says that without these three laws thought and discourse would be impossible. Without them, "nothing we think or say makes any sense, not even this very sentence."
The first law is the Law of Identity, which simply means that a thing is equal to itself. If I have four children then it is true that I have four children. The Law of Identity is used to understand different terms that always refer to the same thing. For example, an unmarried man is a bachelor. Bachelors and unmarried males are different phrases that refer to the exact same property some men have, so any time I use the word bachelor, I can substitute "unmarried man" and it doesn't change them meaning at all. Another example is "God is divine". If we understand the word "divine" to mean pertaining to God, then the sentence just repeats itself; it says the same thing twice. This Law may seem pretty silly, but you'll see how important it is as we come to the next one.
The Second Law is the one that gets to the heart of what we're trying to understand: the Law of Non-Contradiction. The Law of Non-Contradiction says that a thing cannot be and not be at the same time and in the same respect. Using our example above, if it is true that I have four children, then it cannot be true that I do not have four children at the same time and in the same manner. Bachelors cannot be unmarried AND married at the same time. God cannot be both divine and not divine at the same time if we're using the word divine to mean the same thing.
You see, the Law of Non-Contradiction draws the line between true and false statements. Look at the statement "Jesus is God." It would make no sense to say "Jesus is God therefore Jesus cannot be divine." Because of the Law of Identity above, we can see that this statement is really speaking nonsense. Jesus either is God or He isn't. If He is God, then He's divine. He can't be both divine and not-divine at the same time.
The third law is known as the Law of Excluded Middle, and it simply means you have to choose a side. Jesus is either divine or he isn't. Since the Law of Non-Contradiction says he cannot be both then when you have two contradictory statements, you cannot hold to both claims. You must choose one and forfeit the other.
However, note that the Law of Non-Contradiction does specify that we must be talking about the same time and mean the same thing when we point to a claim as contradictory – and this is where most of our critics get into trouble. The claim must be talking about the same time and the same manner or respect. If I travel to New York and pick up a post card for my wife, I'll write on the back "I'm in New York!" and drop it in the mail box. If I fly home the next day, I'll beat that postcard to my home. When my wife does receive the card, she's not going to say "this is a contradiction – you're right here!" It isn't contradictory since the statement was written when I actually was in New York. Similarly, if I'm daydreaming about Tahiti while at my desk in Southern California, I may say "I'm not really here; I'm in Tahiti right now." Again, this isn't a contradiction since I'm using the words "not really here" to talk about a mental state, not a physical presence. So in order for something to be contradiction, it must hold to two opposing claims that mean the same thing at the same time.