A person commits the fallacy of bifurcation when he or she claims that there are only two mutually exclusive possibilities—when, in fact, there is a third option. For this reason the fallacy is also known as the either-or fallacy and the false dilemma.
A facetious example is this:
“Either the traffic light is red, or it is green.”
This is obviously fallacious, since the light could be yellow.1
A more realistic example is this:
“Either you have faith or you are rational.”
This commits the fallacy of bifurcation, since there is a third possibility: we can have faith and be rational. In fact, faith is essential in order to have rationality (e.g., to make sense of laws of logic).2
“Either the universe operates in a law-like fashion, or God is constantly performing miracles.”
This is also fallacious because a third possibility exists: the universe operates in a law-like fashion most of the time, and God occasionally performs a miracle.
Sometimes the origins debate is framed as “faith vs. reason,” “science or religion,” or the “Bible vs. science.” These are all false dilemmas. Faith and reason are not contrary. They go well together (since all reasoning presupposes a type of faith).3
Likewise, science and religion (the Christian religion to be specific) are not mutually exclusive. In fact, it is the Christian system that makes sense of science and the uniformity of nature. Likewise the debate should never be framed as “the Bible vs. science,” since the procedures of science are fully compatible with the Bible. In fact, science is based on the biblical worldview; science requires predictability in nature, which is only made possible by the fact that God upholds the universe in a consistent way that is congenial to human understanding. Such predictability just wouldn’t make sense in a “chance” universe.
The fallacy of bifurcation may be more difficult to spot when the person merely implies that only two options exist, rather than explicitly stating this.
“I could never live by faith because I am a rational person.”
This sentence tacitly presents us with only two options: either faith, or rationality. But, as we’ve mentioned before, these are not exclusive. A rational person must have some degree of faith. So, the Christian takes the third, unmentioned option: faith and rationality.4
“The Bible teaches that ‘in Christ all things hold together.’ But we now know that the forces of gravity and electromagnetism are what hold the universe together.”
This is an example of the fallacy of bifurcation because the critic has implicitly assumed that either (1) God holds the universe together, or (2) gravity and electromagnetism do. However, these are not exclusive. “Gravity” and “electromagnetism” are simply the names we give to the way in which God holds the universe together. Laws of nature are not a replacement for God’s power. Rather, they are an example of God’s power.5
“You must not really believe that God is going to answer your request for healing; otherwise you would not have gone to the doctor.”
The implicit false dilemma here is that either the doctor will help the person or God will. But why can’t it be both? God can use human actions as part of the means by which He accomplishes His will.
On the other hand, in some situations there really are only two options; and it is not fallacious to say so. “Either my car is in the garage, or it is not the case that my car is in the garage” commits no fallacy.6 When Jesus states, “He who is not with Me is against Me” (Matthew 12:30, NAS), He has not committed any fallacy because God is in a position to tell us that there is no third (“neutral”) option. (An attempt to be neutral toward God is sinful and, therefore, non-neutral.)7 The key to spotting fallacies of bifurcation is to watch for cases when only two options are presented (either explicitly or implicitly) and to consider carefully whether or not there is a third possibility.