Suppose that you are a manager for a store. While you are interviewing applicants for a position in one of your departments, you are presented with the following argument:
I need this job. I'm struggling to support a husband with a bad back. I have three children in high school and two in college. It's difficult to make ends meet these days, especially when you are woman my age. So you can see that my need clearly indicated that I deserve a job!
Something in you rebels against this logic. "Not necessarily true, " you think, but what are you objecting to? That she needs the job? No--the evidence she's presented seems to make such a claim reasonable. That she deserves it? She may very well deserve it. It's hard to tell from what she has said.The main problem is that there is a hidden or implicit assumption upon which the woman bases her argument and its conclusion. IT IS THIS: If a person needs something, then he or she deserves to get it. This is what her argument looks like:
If a person needs something, then he or she deserves to get it. (Implicit assumption).
I need this job. (Stated assumption).
So I deserve to get this job. (Conclusion).
It is one of the main characteristics of the implicit assumption that it is an idea about things that the speaker takes so much for granted as being true that he sees no reason to state it explicitly.
Another of the main characteristics is that if someone develops a train of thought based on one or more implicit assumptions, those assumptions are where he/she is most likely to make her mistakes in reasoning. In the above example, for instance, the department store applicant simply assumed that if you need something, then you deserved to get it. An astute listener might realize this and say, "You seem to be suggesting that someone deserves to get something on the basis of need alone. I can think of many cases where this isn't true. Could you perhaps suggest other reasons why you should get the job--such as your qualifications?"Here is another argument containing an implicit assumption:
Giving people grades is a form of punishment, in fact, sometimes quite a severe form of punishment as far as their career or scholarship plans are concerned. Therefore, grades should be abolished.
In order to identify the implicit assumption, first find the main point that the argument is trying to make (its conclusion). The conclusion here is, "Therefore, grades should be abolished." What is, "Giving people grades is a form of punishment"? That is an assumption given to support the conclusion that grades should be abolished. What would it take, then, to complete the argument in such a way that the given assumptions and conclusions would follow from it? "If something is a form of punishment, it should be abolished." Here's the argument:
If something is a form of punishment, it should be abolished. (Implicit assumption).
Giving people grades is a form of punishment. (Stated assumption).
Therefore, grades should be abolished. (Conclusion).
NOTE: What is the purpose of "indeed, sometimes quite a severe form of punishment as far as the career or scholarship plans are concerned . . . ."?
Mainly, it tries to provide support for the assumption preceding it.
So in order to find an unstated or implicit assumption, you do the following:
1. find the argument's conclusion.
2. find the assumption that is providing support for the conclusion.
3. figure out what it would take, given the assumption(s) and conclusion, to complete the argument logically.
Example:
- I, sir, am a teacher and am above criticism!
- Conclusion: I am above criticism.
- Assumption: I am a teacher.
- Implicit Assumption: If someone is a teacher, he or she is above criticism.