ENG 102 – Assessing Reasoning

Here is a quick checklist for assessing reasoning.

Now that you’ve read the Critique Paper article, summarized it and evaluated the evidence, it’s time to analyze its reasoning.

There are different ways to think about reasoning. I will discuss the one that I find most useful. I have written brief explanations of two others, which are linked below (click on “Fallacies’ or “Evidence” to go to those explanations). The three approaches are:

Evaluating premises (also known as assumptions). This is the one I discuss here
Identifying fallacies
Evaluating evidence

I also have some suggestions for your paper. But first, a little background.

Reasoning is the process of moving from the evidence to the conclusion. Notice the terms I have emphasized here: process, from and to.

Reasoning is a process or movement of thought, from one idea or group of ideas (the evidence or premises) to another (the conclusion). It’s all about the relationship between those ideas, rather than either one taken by itself.

When people talk about reasoning, or logic, they tend to be thinking of a process with at least two steps:

If this,
then that.

Assessing reasoning, then, can focus on two aspects of the argument:

The premises, or “if” statements (are they true? are they reasonable?)
The movement from the stated premises to the conclusion (is it valid? does it follow the rules?)

In this document I talk about premises. The document on fallacies discusses the rules for moving from premises to conclusion.

Premises or Assumptions

An assumption is a claim that the author does not even try to prove. She or he simply assumes it is true. Either you accept it or you don’t.

A premise is an assumption on which the argument depends: The conclusion cannot be true unless the premise is true.

There’s a famous syllogism (a type of structured argument) that gets used a lot when teaching logic. It goes like this:

All men are mortal.
Socrates is a man.
Therefore, Socrates is mortal.

The first two statements are premises. You can also think of them as assumptions. The syllogism does not try to prove that they are true. Instead it assumes that they are true, and then claims that, if they are true, the conclusion must be true as well.

One of the tasks involved in assessing reasoning, therefore, is to identify the premises and decide if they are legitimate, reasonable, true. In the example above, the two premises seem reasonable and, as far as we know, true.

A different syllogism might not have such acceptable premises:

All men are purple.
Socrates is a man.
Therefore, Socrates is purple.

Yes—if all men were purple, then Socrates would be purple. But they’re not. In making this assumption, the syllogism fails to convince us, though it might be logically perfect. By evaluating the assumption, or premise, we have evaluated one aspect of the reasoning.

Of course, real–life arguments are rarely so neat or simple. Most of them involve more than two premises, and often some premises are left unstated. The relationships are fundamentally the same, but it can be tricky sorting out all the pieces.

Two Other Points

Assumptions may be explicit or implicit.
- Explicit premises are stated openly, in so many words. The premises of the syllogism above are explicit: All men are mortal; Socrates is a man.
- Implicit premises, on the other hand, are not stated openly. They are implied. They must be true if the conclusion is true, and you can infer them (figure them out) from what the author does say. But they are not stated directly.
Many premises—especially implicit or hidden premises—have to do with values. They are assumptions about the way things are supposed to be. If you’re unable to find any of an author’s hidden premises, start by asking what his or her values are.

To Sum Up

One way to critique someone’s reasoning is to try to evaluate their premises. If you can bring the hidden ones out in the open, you’ll be in a much better position to decide if they are reasonable or not.

Other Approaches

There are other ways to analyze and evaluate reasoning. I have written brief explanations of two of them. One talks about fallacies, which is how many sources and people discuss reasoning, and the other talks about how you can evaluate reasoning by looking at the evidence.

Your Paper

This section refers to your Critique Paper. For the homework leading up to the paper I just want you to take notes on 2 or 3 points in the assigned reading and decide what you think of the reasoning. Is it valid? Are the premises reasonable?

When you assess the article’s reasoning in your paper, you may use any of these approaches that works for you (the one described above, or identifying fallacies, or evaluating evidence). What I want to be sure you do is include a section that specifically addresses reasoning, whether by talking about premises, fallacies or evidence.

Points to Keep in Mind

Don’t assume you must find flaws in the reasoning. Maybe you think it’s all just dandy. If that’s the case, you’ll need to explain why you find it convincing. Probably the easiest way to do this is to identify some premises and state why you think they are reasonable. (Obviously, using the fallacies approach won’t work if you think the reasoning is flawless.) It might help to explain why some people might think that the reasoning is flawed and then explain why you disagree.