Class 7 - Logic and Argumentation
Welcome back
Welcome back. In this session, we are be exploring how to think about arguments in a more structured and logical fashion. The reading for this session is the first chapter in the open textbook on logic that can be found here: https://press.rebus.community/intro-to-phil-logic/chapter/chapter-1/
Discussion
To get started, we’ll look at the introduction to this chapter. It is a curious passage. Here are some questions.
- Reason is the thing that distinguishes us from “the beasts of the field.” Do you think this is true?
- In logic, the main criterion is not the effectiveness of arguments (do they successfully persuade), but instead their correctness. How do you understand the difference between effectiveness and correctness?
- The author references Hitler for his bad (that is, illogical) arguments that are also bad (that is, used for unethical ends). In what ways can the study of logic save us from the harm of bad arguments?
- Are bad (illogical) arguments always bad (unethical)? Or can an argument be bad (illogical), but also good (used for ethical ends)?
Basic terms
We’re now going to look at some basic terms. In groups, talk about the following questions. What do you understand by the terms:
- Propositions
- Declarative sentences
- Arguments (in a formal sense)
- Premises
- Independent premises
- Intermediate premises
- Joint premises (also called co-premises, or dependent reasons)
- Tacit premises
- Conclusions
Diagramming arguments
Finally, I’m going to get you working in pairs or threes. We’re going to look at one exercise from the end of this chapter. Let’s take question number 2, as it is interestingly complex. We’ll look at it here:
Abolish the death penalty! Why? It is immoral. Numerous studies have shown that there is racial bias in its application. The rise of DNA testing has exonerated scores of inmates on death row; who knows how many innocent people have been killed in the past? The death penalty is also impractical. Revenge is counterproductive: “An eye for an eye leaves the whole world blind,” as Gandhi said. Moreover, the costs of litigating death penalty cases, with their endless appeals, are enormous.
The first job to do is to identify the conclusion and identify the premises.
Next, establish whether these are independent premises, whether they are intermediate premises, or whether they are joint premises. In this particular example, we’re not going to worry about tacit premises.
Finally, in your pairs, diagram this argument, and be ready to share your screen with your diagram, where we will explore it together.
You can do this on paper, or use the diagramming app https://argumentation.io/. Don’t worry about the boxes that say “inference.” We’ll move onto this aspect of argumentation in the next session.
Finally, if you do use the argumentation.io tool, you can’t save your argument map unless you sign up for an account. But you can always share a screenshot.
Homework
Hopefully, this has given you a taste for breaking down arguments into their component parts. For the next session, I want you to read the next chapter:
https://press.rebus.community/intro-to-phil-logic/chapter/chapter-2-evaluating-arguments/