Lords of Brain

This is a philosophical perspective to logical argument concerning common fallacies contained in the argument.

I have previously made clear the elements of an argument:  the premise, evidence, and conclusion.  Along with these I explored the necessary and sufficient conditions of the premise and how the evidence presented must be independent from and supportive of the conclusion.  I further presented some common fallacies of logical argument that used (or mis-used) these points.

When creating an argument, it is very important that you explore and understand these fallacies so that you do not commit their mistakes.  However, there are as many fallacies in logical arguments as there are actual arguments.  In this paper, I shall concentrate on some of the lesser fallacies.  Lesser in this case meaning apart from those presented in Part 1 of this series . . .  they are just as fallacious as those presented in Part 1, but are somewhat less obvious to spot.

Black or white fallacy:  This fallacy occurs when one attempts to resolve an argument into only two choices (black or white; good or evil; true or false) when other choices may exist.  A good example of this is a debate on religion.  “If Wilhelm is not Christian then he must be atheist.”  If one resolves the argument to these two choices, then you have ignored other religions:  Buddhism, Muslim, Hindu, and hundreds of other religious philosophies that exist in the world.  There is often more than one alternative to any argument and care must be taken to include them all.  Note that the black or white fallacy can be committed any time the number of alternatives given are less than the actual number of alternatives that exist:  three instead of four, or nine instead of twelve.

Ad hominem:  Taken from Latin (which means “to the man”), ad hominem fallacies take attention away from the evidence and directs it to the source of the evidence (or the character of the person presenting it) in an attempt to discredit the validity of the evidence.  If Garth were to make a staement that refutes a portion of the Bible, an ad hominem fallacy would be committed if on were to say, “Garth is ignorant of the subject since he is not a Christian.”  This works only if all non-Christians are ignorant of the Bible, which is not a valid assumption.  When evidence is presented in any argument, we must disassociate the evidence from the source.  The evidence may be valid, even if the source is not.  If the evidence is invalid it should fail (or succeed) on its own merit.

Sometimes the background of a source can justify his evidence.  The opinion of a professor of physics, for example, can lend credence to an argument that supports Einstein’s special theory of relativity.  The professor of physics very likely has detailed knowledge on the subject and advertising his status as a professor of physics would help in furthering the argument in favor of special theory.  However, making claims on his character, (that he is a democrat or a non-Christian) which are irrelevant to the subject would be committing the ad hominem fallacy.

Fallacy of Origin:  Similar to the ad hominem fallacy, the fallacy of origin attempts to discredit the origin of a practice or belief without taking into consideration its current role.  “Soft Drink A was originally created as a ‘snake oil’ tonic by a charlatan.”  This could be evidence in support of Soft Drink B; however, it fails to take into account the evolution of Soft Drink A into a palatable beverage.  Similarly, some of our medical knowledge stems from the result of biological testing performed during the holocaust in Germany, yet in today’s role, it saves many thousands of lives each year.  When examining such arguments we must focus on its role now, not its origins.  Again, if the evidence is unsound, then it will fail of its own accord.

Fallacy by exaggeration:  Exaggeration may occur in an argument in one of two forms, the first exaggerates the premise of an argument; the second exaggerates the conclusion.  During an argument, an opponent may exaggerate the original conclusion so that in may more easily be attacked.  This is a fallacy more easily represented by example.  A candidate for political office could make a statement in favor of raising taxes on tobacco and alcohol.  His rival may then attack him with a counter statement, “My opponent is in favor of raising taxes.”  By raising the stakes from raising taxes on tobacco and alcohol to all taxes, he has committed an Exaggeration fallacy.

The second form of fallacy by exaggeration distorts the conclusion in such a way as to suggest that the consequences of a particular view or action will result in future negative actions.  “If we support Policy X, then Y will result.”  It should be understood here that Y is generally undesirable.  If one can offer evidence that Y will, in fact, occur, then we have avoided this type of fallacy by exaggeration.  The key point to remember here is that unsubstantiated allegations result in this type of exaggeration.

This is a philosophical perspective to logical argument concerning the premise, evidence, and conclusion.

In logical argument a premise must exist.  A premise can be expressed as: “If A, then B.”  The premise expresses the logical relationship between the theory (A) and the assumption (B).  The philosopher is not concerned with the cause and effect so much as the logical chain of events between theory and assumption.  We call this logical chain of events, conditions.

The two primary conditions that exist in philosophical argument are necessary conditions and sufficient conditions.  Let’s explore the differences between the two.

If the assumption relies on the theory, then the theory is a necessary condition.  In other words, if A must exist in order for B to exist, then A is a necessary condition.  For example:  If I have an orange, I must peel it before I can eat it.  Therefore, peeling the orange is a necessary condition for me to eat the orange.  However, just because you have a necessary condition, it does not follow that B must occur.  I have peeled the orange and supplied the necessary condition, but I do not have to eat the orange.

This takes us nicely into the sufficient condition.  If the assumption (B) must follow the theory (A), then A is said to be a sufficient condition.  For example:  If I strike a match, then (given the presence of oxygen) the match will burn.  We can see that striking the match is a sufficient condition.

It follows that a sufficient condition is also a necessary condition; however, necessary conditions (by themselves) are not sufficient conditions.

We have now established the elements of a premise.   We can now use this premise to offer evidence in support of a conclusion.  It is important that evidence given must be independent from and supportive of the conclusion.

Suppose one wants to argue in favor of capital punishment.  One could construct the premise, “If a person is convicted of murder, he should be executed.”  Evidence could be given as:  “Capital punishment would prevent future murders from the convicted criminal, and is an effective deterrent against would-be criminals.”  At this point, we are not as concerned with the validity of that claim as we are with it being independent from and supportive of the conclusion (in the case, the enactment of the death penalty).  In this argument, we have established premise, evidence and conclusion.

The evidence is independent from the conclusion; which is to say, the conclusion does not have to exist for the evidence to be true.  It would be quite another thing if we offered the evidence to be, “Executions are a deterrent because we have capital punishment laws.”

The evidence also supports the conclusion.  If we can accept the evidence as truth, then it would follow that we could accept the conclusion as truth.

Now, we can begin to look at some common logical fallacies in argument.

Circular argument:  A circular argument presents evidence that is not independent of the conclusion.  “Capital punishment should be required of all murderers because they should be executed.”  In this case the evidence is essentially the same as the conclusion, and there is no independence.

Consider the following, “Carl is telling the truth because James says he is, and James believes him because Carl told him the truth.”  The conclusion, “Carl is telling the truth,” depends on the evidence, “James says he is.”  The problem is that the evidence relies on a second premise, the conclusion of which requires Carl to be telling the truth, which is the original conclusion.  Again, the conclusion depends on itself and is a circular argument.

Begging the question:  When evidence is presented in support of a conclusion that rules out any other possibility, it is said to be begging the question.  Carl could make the claim, “all Americans believe in capital punishment.”  Wayne could present the argument that James, an American, does not support capital punishment.  Carl might claim, “Then James is clearly not an American.”  Carl has redefined “American” so that his original conclusion is true, and has committed the fallacy of begging the question.

Non Sequitur:  From the Latin, “does not follow,” the non sequitur is used to describe a premise whose evidence (while being independent from) does not support its conclusion.

Sometimes evidence does not support the conclusion because there is no relation between the two:  “Carl is telling the truth because he is a democrat.”  Being a democrat offers no relation to Carl’s honesty (despite what a republican may claim) and cannot be used to support that conclusion.

In other non sequiturs, the evidence may support the conclusion, but only secondarily or, in actuality, supports a slightly different conclusion.  “Lowering taxes would be beneficial to Americans because it would allow them to keep more of their income.”  The evidence would seem to support the conclusion (of lowering taxes); however, it makes no statement of other social concerns, which may arise as a result of lowering taxes (fewer prisons, lower wages in public schools, reduced maintenance on public roads, etc.).

Any time a sufficient condition is required for the evidence to support a conclusion, a non sequitur occurs when only a necessary condition is given.

Look for Part 2 (coming soon) in which we explore even more logical fallacies of argument.