Skip to content

The Necessary-Sufficient Factor: Combating an Atheist Fallacy

By: Jonathan Harris

Last semester the Christian Fellowship held an event at Dutchess Community College promoting Ben Stein’s latest documentary, “Expelled-No Intelligence Allowed.” The point of the viewing was to inspire discussions between committed Darwinists and Theists whether they were part of the student body or faculty on campus. Of course an even bigger objective was to gain a hearing for the Gospel within this discussion as a Christian world-view was presented. During the post-film open-forum styled discussion, one of the staunch Darwinists who was present (and being extremely rude with his comments throughout the whole entire film I might add), decided to attack a particular point made in the film, that point being the Darwin-Hitler relationship. For those who haven’t seen the film, Ben Stein makes a connection between Darwin and Hitler, as do the experts he interviews. It is pointed out that Hitler thought he was progressing evolution through the mass murder of several million Jews. They were inferior, or so he thought, therefore society would evolve better without their presence. In Hitler’s mind, he was doing the world a favor. Anyway, this particular gentlemen had a problem with this depiction of Darwinism. He stated that, “Christians during the inquisition and crusades did their evil deeds in the name of religion, whereas Hitler did what he did in spite of his belief in Darwinism.” In other words, Darwin didn’t inspire Hitler to kill Jews, therefore the whole connection Ben Stein forwarded was without merit. Of course, there was much emotion associated with his response as he proceeded to blame Christians for the world’s ills. Besides the fact that his whole manner of argument was bait and switch (i.e. making a statement and then switching the subject to another attack before reconciling the first issue), there was an even bigger problem with his logic, and the logic of many atheists. It is called the Necessary-Sufficient factor. Let me give a brief illustration:


“In order to be in New York, you must be in the United States.”

It follows logically therefore that:

“If you’re not in the United States, you’re not in New York.”

However, it would be wrong to say,

“If your not in New York, you’re not in the United States.”

The logical term for the above fallacy is, “false contrapositive.” It confuses what’s necessary, and what’s sufficient in the relationship. It is necessary to be in the United States in order to be in New York, and it is sufficient to be in New York in order to claim that you’re in the United States, however, it’s wrong to say that it’s necessary to be in New York to be in the United States. Why? Because you could be in another state and still be in the U.S.. It doesn’t have to be New York. Akin to this simple example is the relationship between Darwin and Hitler:

Statement (made by Ben Stein):

“Since he believed evolution, Hitler thought his actions were justified”

We could also say:

“Hitler would not have thought his actions were justified, if he did not believe in evolution”

However, we couldn’t say:

“If he didn’t believe in evolution, Hitler would not have thought his actions justified.”

Why? Because, evolution was a sufficient reason for Hitler to kill, but not a necessary one. There may have been other reasons for Hitler to kill people, but evolution was a sufficient justification he employed. Not everyone who believes in evolution, will be a mass murderer. The Atheist loves to take a sufficient statement and make it necessary, or a necessary statement and make it sufficient. Let me give you another example:

Christian: “I do good things, because it pleases Christ.”
Atheist: “You don’t have to be a Christian to do good works, Atheists do them too.”

What the Atheist says may be true, but he confused the Christian’s statement that it is “sufficient” to be a Christian in order to do good works with what is “necessary to be a Christian…etc.”

Be on the lookout for little tricks like this. Professors and “skeptical” students will use them all the time.

Leave a Reply

Your email address will not be published. Required fields are marked *