LESSONS IN LOGIC: What Do We Mean By ‘Argument?’

Have you ever found yourself in a debate with someone who suddenly accuses you of not answering their argument?  Or maybe they claim you haven’t made an argument.  Would you know how to handle either of these situations?  Better yet, would you know how to determine whether or not the person making these claims knows what they are asking you?  Truth is, very few of us know what we mean when we say ‘argument,’ and with good reason.  It is a complicated subject.  For example: there are three basic types of arguments, with slightly different rules governing how each one works.  However, all three types of arguments has a few things in common, and this post proposes to explain the basics so that — if you ever encounter either of the situations I just described — you will be better prepared to deal with it.

First, when most people think of the word, ‘argument,’ they think of a heated exchange between two or more individuals.  Well, this is not the type of argument we will be discussing.  It may be better if we refer to the topic at hand as ‘formal,’ ‘logical‘ or ‘persuasive‘ arguments.  Whatever term we use, we are discussing an argument that is actually constructed for the purpose of persuading others to accept an assertion or conclusion.  It can also be made to defend a position.  And, in all cases, it conforms to a set of general rules that govern how they are constructed and evaluated.

Now that we have that part out of the way, we need to be aware of the fact that there are two main divisions of ‘argument.’  They are usually referred to as ‘formal arguments,’ and ‘informal arguments.‘  Formal arguments consist of either deductive or inductive reasoning.  They are governed by a very strict, highly structured set of rules.  Fortunately, they are usually only found in more scholarly settings.  The average person seldom encounters such arguments.  Informal arguments are much more common and can be either deductive or inductive in nature.  Informal arguments are still governed by the same rules as formal arguments, but the application of those rules is much less structured.  The most common place the average person encounters informal arguments is in persuasive essays, such as those we find in editorial pages and even on blogs such as this one.  In fact, persuasive writing is based on informal argumentation.

Before we continue, let us recap what we have so far.  We are dealing with logical arguments, not heated exchanges.  Logical arguments are designed to make and defend a claim.  They can be formal or informal.  Formal arguments can be inductive or deductive and are highly structured.  Informal arguments can also be deductive or inductive, but are much less structured.  Either way, bot forms of argument are governed by the rules of logic.  Once we understand these basic points, we are ready to look at the basic parts of an argument:


Now, let’s cover these parts in a little more detail:

THESIS — this is the thing our argument is meant to prove or defend.  It includes ‘qualifiers.’  Qualifiers are a set of statements that describe the particular aspects or conditions under which our claim/assertion is true.

EVIDENCE — this is a list of facts, figures or other materials we are using to support or defend our thesis.

LOGICAL CONNECTION — this is where we explain the reasoning between our evidence and our thesis.  It is where we connect the dots for the reader to follow.

CONSIDERATION OF OPPOSING VIEWS — this is where we acknowledge the strongest arguments against our thesis, and we describe those counter arguments  faithfully.  We do not try to twist or weaken them.

REFUTATION — this is where we then explain why these counter arguments should not be accepted and why our thesis should prevail.

Remember that our argument can be deductive or inductive.  Deductive arguments are the strongest.  If your reasoning is solid, a deductive argument can seldom be defeated (in logical terms, a defeated argument is said to have been ‘broken’).

A ‘deductive‘ argument is one in which the evidence naturally follows and inevitably leads to the conclusion of our thesis.  In short, A leads to B leads to C and if they are all true, then the conclusion must be true — period!  A classic example is:

My pond is full of water.

All fish in my pond are wet.

Bill is a fish in my pond.

Therefore, Bill is wet.

If it is true that all fish in my pond are wet, and it is true that Bill is a fish in my pond, then Bill must be wet — period!

An ‘inductive‘ argument is based on the likelihood of the conclusion of our thesis being true based on the strength of our supporting evidence.  An example of an inductive argument would be:

The sun came up today.

The sun came up yesterday.

The sun has come up for the last 3,000 years.

Therefore, the sun will come up tomorrow.

There is no way to ‘prove’ (i.e. the ability to ascertain the truth with 100% confidence) the sun will come up tomorrow.  All we can do is evaluate the claim that it will come up tomorrow based on the strength of the evidence provided.  In this case, we have created a strong inductive argument, but it is not as strong as our deductive argument.

Now that we know how a formal argument is constructed, we need to know a little bit about how to evaluate it.  Before we accept the thesis of any argument, we should check to make sure it is ‘sound,’ ‘valid‘ and ‘rational.’

VALID — for simplicity’s sake, ‘valid’ means that, if our evidence is true, then our conclusion has to be true.  Our first argument is valid because, if the evidence is true, then it absolutely must be true that Bill is wet.

SOUND — to be sound, an argument first has to be valid.  This means the conclusion has to be true if the evidence is true.  But — in this case — the evidence has to be — in fact — true. This can be a little more difficult to understand, so let’s look at this issue in more detail.

Going back to Bill, the fish, you will notice that I was very careful in constructing that argument.  If my pond is full of water, then all fish in it are wet, and if Bill is a fish in my pond, he has to be wet — period!  This means my argument is valid.  However, if there actually is water in my pond (and there actually is — I can see it as I write this), then my argument is also sound — because all my evidence is factually true.  But what if there was no water in my pond?  In that case, my evidence would not be true, therefore, my argument would not be ‘sound.’

Again, there is more to this.  It does get complicated, but we are just trying to cover the basics here.  Therefore, when you are trying to evaluate an actual argument, start by asking yourself these questions:

Is it valid?  If all the evidence is true, does it mean the thesis/conclusion has to be true?

If it sound?  Is all the evidence actually true?

This leaves us with one last point we need to cover about how to evaluate an argument.  We need to check to make sure it is ‘rational:’

RATIONAL — again, for the sake of simplicity, this is where we check to make sure there are no fallacies in an argument.  Fallacies are mistakes in the rules of logic, and any thesis or conclusion based on such a mistake is defined as ‘irrational‘ (i.e. not rational).

But we also have to check to make sure the conclusion is believable.  It is possible to make an argument that is valid and sound and has no logical mistakes, yet it can still be considered to be irrational.  And example would be:

Marvin the Martian has a ray gun.

Marvin the Martian is trying to shoot Bugs Bunny with his ray gun.

Therefore, Bugs Bunny should hide.

In the world of Loony Tunes, there is a Marvin the Martian.  He does have a ray gun.  He has wanted to shoot Bugs Bunny.  Bugs Bunny did try to hide.  Therefore, this argument is valid and sound.  There are no mistakes in the reasoning here, but that does not mean this argument is rational.  Why?  Because the world of Loony Tunes is imaginary: it does not exist in the real world, and things that do not exist in the real world are — by definition — irrational.

Let’s review before we end.  We now know what we mean by ‘argument,’ and that there are formal and informal arguments.  We also know there are deductive and inductive forms of formal and informal arguments.  We know that deductive arguments are the strongest.  We know all arguments need to contain the five points or parts of an argument.  We also know that an argument needs to be valid, sound and rational.  But we have not covered what we do if we find an argument that is not valid, sound and rational.

If and when we encounter an argument that is not valid, sound and rational, we are free to dismiss its thesis/conclusion.  This is because the argument has failed.  Furthermore, if we actually demonstrate that it is irrational, we are said to have broken the argument.  Either way — even if the thesis/conclusion happens to be true — we are still within the rules of logic to dismiss it because the argument is irrational.  In other words, it is not reasonable.  That means the thesis/conclusion may have been true simply by accident, and no sane person bases their lives on the evidence of things that happen simply by random chance?



Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s