Finding questionable assumptions
We know intuitively that we have to give reasons in order to convince people of a claim we are trying to make. But reasons don’t lead to claims on their own. They depend on underlying assumptions. In order to make that leap in the direction of the arrow from a reason to a claim, certain foundational ideas are necessary, ideas that may be hidden, that the writer may not even be aware of.
Noticing and questioning assumptions is one of the mental habits that college cultivates. It’s a habit we may find empowering, freeing, and useful in any area of life. Suddenly seeing a critical assumption that we have never recognized can make for one of those satisfying "Aha!" moments. Once we can talk about all the ideas an argument depends on, we can explore more possibilities for how to think about it.
So if we are reading an argument, how do we identify the assumptions it makes? In some cases writers will point out their assumptions with phrases like the following:
- I will assume here _____________.
- This rests on the assumption that _____________.
- Of course, this depends on _____________.
- As we know _____________.
- This argument rests upon the idea that _____________.
- The underlying principle here is that _____________.
More commonly, though, writers do not state assumptions, sometimes because they seem obvious and sometimes because drawing attention to the assumptions might draw attention to a weakness in the argument. However, when we want to understand an argument fully, we can figure out many of the assumptions on our own. There is no magic formula for doing this, but the basic method is to ask ourselves what the reason needs to get us to the claim. What is behind the arrow, the leap from reason to claim? What underlying idea does that leap depend on? For example, we can see fairly readily that in the border argument, the first arrow depends on the idea that what we consider right for ourselves we should consider right for other people.
In the above example, most people would probably agree that we should apply the same standards to ourselves as we do to others. So we have identified an assumption that seems uncontroversial. We could also note that the above example also depends on the assumption that "People currently need permission to cross the border legally." We know that under current policy, governments decide whether or not to allow people in. However, we may wonder how useful it is to identify assumptions that are so basic and uncontroversial. In fact, we do not need to find every possible underlying assumption in order to assess an argument. We need to focus on assumptions that might not be true or that might not be universally accepted. How can we target those?
One way to uncover problematic assumptions is to brainstorm cases where the reason wouldn't necessarily lead to the claim. We can put the reason and the claim into the following question:
Just because [reason] does that necessarily mean that [claim]?
If we can think of a case in which the reason doesn't lead to the claim, then there must be a problematic assumption. We can try to find this assumption by filling in the "scenario" blank below with a case in which the reason was true but the claim was not. This technique is sometimes called a scenario test:
Just because [reason] that doesn't mean [claim] because it could be that...[scenario].
For example, in the case of the border argument, we could write, "Just because we would feel it was right to cross the border without permission doesn't necessarily mean that we must recognize illegal crossing as ethical because it could be that..." I am tempted to complete this with the idea that "our personal feelings are not always the best guide to ethics." Or I could complete it with a more specific case: "It might be that crossing without permission isn't really right even though some people might feel it is." This helps us to identify another assumption--that we can tell if something is ethical by whether or not it feels right.
Looking for Counterexamples
Once we have found a questionable assumption, we can test it further by looking for cases unrelated to our argument that might prove it wrong. We can probably think of a person who sincerely believes they are doing right, while we are sure their action is unethical. A suicide bomber may believe they are doing God's will by killing people. If we can think of a counterexample, we can feel confident that the assumption in question is not universally true.
Phrases for critiquing assumptions
Once we have identified an assumption that we want to question, we can introduce the assumption and explain its weakness with it with phrases like the following:
- _____________implies/assumes/relies on the idea that _____________; however, _____________.
- _____________takes for granted that _____________, but we may wonder whether this is a justified assumption because_____________.
- _____________depends on the assumption that_____________. Is this always the case? Some might say that _____________.
- _____________ depends on a belief in _____________, which may not be shared by all readers because _____________.
- The underlying idea here is that _____________; however we must ask ourselves whether _____________.
- The implicit assumption is that _____________ but some may question whether, in fact, _____________.
How much of a problem is the questionable assumption?
As they read our assessment, others will want to know how any problems we identify fit in to our overall take on the argument. Is the questionable assumption a major or a minor issue? Could the argument easily be revised to correct the problem, or does it completely undermine the validity of the argument? An assessment of the strength of the argument might include a reflection like the following:
Should we really accept illegal border crossing as the right thing to do? Mills argues that if we would consider it right in our own private lives under desperate circumstances, we should consider it ethical generally. Most of us would have to agree that if we consider something right for ourselves, we should consider it right for others. However, we can also see that feeling something is right doesn’t necessarily make it so. Some mass shooters have a sincere belief that they are doing God’s work. Is our personal sense of morality about a family's decision to immigrate really a strong basis for immigration policy? Mills' failure to address this crucial question undermines her argument.