Critical Thinking: Defining an Argument, Premises, and Conclusions

Defining an Argument
Argument: vas is das? For most of us when we hear the word ‘argument’ we think of something we’d rather avoid.  As it is commonly understood, an argument involves some sort of unpleasant confrontation (well, maybe not always unpleasant–it can feel pretty good when you win!).  While this is one notion of ‘argument,’ it’s (generally) not what the term refers to in philosophy.

In philosophy what we mean by argument is “a set of reasons offered in support of a claim.”  An argument, in this narrower sense, also generally implies some sort of structure.  For now we’ll ignore the more particular structural aspects and focus on the two primary elements that make up an argument: premises and conclusions.

Lets talk about conclusions first because their definition is pretty simple.  A conclusion is the final assertion that is supported with evidence and reasons.  What’s important is the relationship between premises and conclusions.  The premises are independent reasons and evidence that support the conclusion.  In an argument, the conclusion should follow from the premises.

Lets consider a simple example:
Reason (1): Everyone thought Miley Cyrus’ performance was a travesty. 

Reason (2):  Some people thought her performance was offensive.
Conclusion:  Therefore, some people thought her performance was both a travesty and offensive.

Notice that so long as we accept reason 1 and reason 2 as true, then we must also accept the conclusion.  This is what we mean by “the conclusion ‘follows’ from the premises.”

Lets examine premises a little more closely.  A premise is any reason or evidence that supports the conclusion of the argument.  In the context of arguments we can use ‘reasons’, ‘evidence’, and ‘premises’ interchangeably.  For example, if my conclusion is that dogs are better pets than cats, I might offer the following reasons:

(P1) dogs are generally more affectionate than cats and
(P2) dogs are more responsive to their owners’ commands than cats.

From my two premises, I infer my conclusion that

(C) dogs are better pets than cats.

Lets return to the definition of an argument.  Notice that in the definition, I’ve said that arguments are a set of reasons.  While this isn’t always true, generally, a good argument will generally have more than one premise.  

Heuristics for Identifying Premises and Conclusions
Now that we know what each concept is, lets look at how to identify each one as we might encounter them “in nature” (e.g., in an article, in a conversation, in a meme, in a homework exercise, etc…).  First I’ll explain each heuristic, then I’ll apply them to some examples.

Identifying conclusions:  
The easiest way to go about decomposing arguments is to first try to find the conclusion.  This is a good strategy because there is usually only one conclusion so, if we can identify it, it means the rest of the passage are premises. For this reason, most of the heuristics focus on finding the conclusion.  

Heuristic 1:  Look for the most controversial statement in the argument.  The conclusion will generally be the most controversial statement in the argument.  If you think about it, this makes sense.  Typically arguments proceed by moving from assertions (i.e., premises) the audience agrees with then showing how these assertions imply something that the audience might not have previously agreed with.

Heuristic 2:  The conclusion is usually a statement that takes a position on an issue.  By implication, the premises will be reasons that support the position on the issue (i.e., the conclusion).  A good way to apply this heuristic is to ask “what is the arguer trying to get me to believe?”.  The answer to this question is generally going to be the conclusion.

Heuristic 3:   The conclusion is usually (but not always) the first or last statement of the argument. 

Heuristic 4:  The “because” test.  Use this method you’re having trouble figuring which of 2 statements is the conclusion.  The “because” test helps you figure out which statement is supporting which.  Recall that the premise(s) always supports the conclusion.  This method is best explained by using an example.  Suppose you encounter an argument that goes something like this:

It’s a good idea to eat lots of amazonian jungle fruit.  It tastes delicious.  Also, lots of facebook posts say that it cures cancer

Suppose you’re having trouble deciding what the conclusion it.  You’ve eliminated “it tastes delicious” as a candidate but you still have to choose between “it’s a good idea to eat lots of amazonian jungle fruit” and “lots of facebook posts say that it cures cancer”.  To use the because test, read one statement after the other but insert the word “because” between the two and see what makes more sense.  Lets try the two possibilities:

A:  It’s a good idea to eat lots of amazonian jungle fruit because lots of facebook posts say that it cures cancer.

B:  Lots of facebook posts say that amazonian jungle fruit cures cancer because it’s a good idea to eat lots of it. 

Which makes more sense?  Which is providing support for which?  

The answer is A.  Lots of facebook posts saying something is a reason (i.e. premise) to believe that it’s a good idea to eat amazonian jungle fruit–despite the fact that it’s not a very good reason…

Identifying the Premises
Heuristic 1:  Identifying the premises once you’ve identified the conclusion is cake.  Whatever isn’t contained in the conclusion is either a premise or “filler” (i.e., not relevant to the argument).  We will explore the distinguishing between filler and relevant premises a bit later, so don’t worry about that distinction for now.

Example 1
Gun availability should be regulated. Put simply, if your fellow citizens have easy access to guns, they’re more likely to kill you than if they don’t have access. Interestingly, this turned out to be true not just for the twenty-six developed countries analyzed, but on a State-to-State level too.http://listverse.com/2013/04/21/10-arguments-for-gun-control/

Ok, lets try heuristic #1.  What’s the most controversial statement?  For most Americans, it is probably that “gun availability should be regulated.”  This is probably the conclusion.  Just for fun lets try out the other heuristics.

Heuristic #2 says we should find a statement that takes a position on an issue.  Hmmm… the issue seems to be gun control, and the arguer takes a position.  Both heuristics converge on “gun availability should be regulated.”

Heuristic #3 says the conclusion will usually be the first or last statement.  Guess what? Same result as the other heuristics.

Heuristic #4.  
A:  Gun availability should be regulated because people with easy access to guns are more likely to kill you. 

Or

B:  People with easy access to guns are more likely to kill you because gun availability should be regulated.

A is the winner.

The conclusion in this argument is well established.  It follows that what’s left over are premises (support for the conclusion):
(P1)  If your fellow citizens have easy access to guns, they’re more likely to kill you than if they don’t have access. 
(P2)  Studies show that P1 is true, not just for the twenty-six developed countries analyzed, but on a State-to-State level too. 
(C)  Gun availability should be regulated.

Example 2
If you make gun ownership a crime, then only criminals will have guns. This means only “bad” guys would have guns, while good people would by definition be at a disadvantage. Gun control is a bad idea.
Heuristic #1:  What’s the most controversial statement? Probably “gun control is a bad idea.”

Heuristic #2: Which statement takes a position on an issue? “Gun control is a bad idea.”

Heuristic #3:  “Gun control is a bad idea” is last and also passed heuristic 1 and 2.  Probably a good bet as the conclusion. 

Heuristic #4:  
A: If you make gun ownership a crime, then only criminals will have guns because gun control is a bad idea.

OR

B: Gun control is a bad idea because if you make gun ownership a crime, then only criminals will have guns.


The winner is B, therefore, “gun control is a bad idea” is the conclusion. 

All 4 heuristics point to “gun control is a bad idea” as being the conclusion therefore we can safely infer that the other statements are premises:

(P1)   If you make gun ownership a crime, then only criminals will have guns.
(P2)   This means only “bad” guys would have guns, while good people would by definition be at a disadvantage.
(C)     Gun control is a bad idea.

Looking Ahead
Also, many arguments can also contain what are called ‘hidden’, ‘unstated,’ or ‘assumed’ premises.

To understand the notion of a hidden premise lets look at (P1).  Can you find the hidden premise?  Here it is: (HP1) What makes a good pet is that it is affectionate.  This is an assumption that displays the values of the arguer.  (Note: hidden premises might not always be about values.)

However, there may be people who don’t value affection as a marker of being a good pet.  Maybe for some people what makes a good pet is that it is clean or self-reliant.  So, a huge part of being a good critical thinker is to look beyond the stated premises and to try to find the assumed premises.  When we do this, the task of assessing the relative strength and weaknesses of an argument’s premises (and, in turn, the argument itself) becomes much easier.

A cat lover could now counter the dog-as-better-pets argument by showing that the hidden assumption upon which the relevance of (P1) relies isn’t universally true, and therefore the conclusion doesn’t necessarily follow.

So, the cat lover can show that (C) (dogs are better than cats) doesn’t necessarily follow from (P1) (dogs are more affectionate than cats) because (P1) is only relevant to the conclusion if we also assume that affection-giving is a key determinant of ‘good pet-ness’.  In other words, the dog proponent’s argument only works if we also accept their hidden assumption/premise. 

However, showing that (C) doesn’t follow from (P1) doesn’t mean (C) is false, nor does it show the contrary, that cats are better pets than dogs, it only shows that “dogs are better pets than cats” can’t be established through this particular argument.

In other words, it could very well be true that dogs are better pets than cats but this argument doesn’t show it.  In order to prove that dogs are better than cats we’d need a different argument. 

This brings us to an interesting point which I’ll discuss in the next section: systems of belief, biases, and values.  When (as often happens) arguments involve values, evaluating an argument as ‘true’ or ‘false’ becomes difficult because it is an open question whether a value (that is supporting a major premise or conclusion) can be ‘right’ or ‘wrong’.  This is more a question for ethics, but as far as being good critical thinkers goes, it  is extremely important to be able to recognize when and how a premise or conclusion is ultimately supported by a value judgement, bias, or system of belief.

The next post will give an overview of systems of belief, biases, and values, and their role in arguments and critical thinking.

Summary:
An argument is a set of reasons or evidence offered in support of a claim.


A premise is an individual reason or piece of evidence offered in support of a conclusion.

A conclusion is the claim that follows from or is supported by the premise(s).

Key ideas:
1) Just because a conclusion is true, it doesn’t mean that the argument in support of the conclusion is a good one (i.e. valid).  Truth and justification are two different things!


2)  Be on the alert for hidden premises! 

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