5
Autobiographical subject matter: This section will focus on a challenge you have faced, and your response to that challenge.
Logical skills involved:
- Creating a valid argument
- Demonstrating validity using appropriate logical methods
Worksheet instructions: Identify a challenge you have faced at some point in your life. It can be a major challenge or a relatively minor one, although it’s best not to pick something too trivial because it will be less interesting. It can be recent, or from childhood. On the top of the worksheet, express the challenge itself in a single sentence, in English.
Think of a valid argument that expresses some aspect of what your response was to that challenge. Your argument should have two or three premises, plus a conclusion. It can be a propositional logic argument or a categorical argument. Write out the argument. If it’s in propositional logic, be sure to include a key stating what atomic sentence each letter stands for. If it’s a categorical argument, make sure the premises and conclusion are all phrased as categorical propositions having A, E, I, or O form. Aim to make your argument sound too – or at least reasonably plausible.
In the bottom box, demonstrate that the argument is valid. Select a method that makes sense given the content of your argument! Recall that you have learned at least three methods of demonstrating validity: truth tables, formal proofs, and Venn diagrams. Select a method that will work for the type of argument you wrote.
Advice and things to keep in mind
Thinking of a valid argument (about content you write yourself) can be difficult. For ideas of a valid structure, look back at the many examples we’ve seen throughout the term in the texts and in class. While the content of your argument will need to be your own, validity is a matter of form. That’s useful to know! Each of the proof rules has a valid form. There are many exercises in the texts that give valid forms for two-premise arguments. It is perfectly fine if you use a form that was already shown to be valid.
In choosing whether to use propositional or categorical logic, it is entirely a matter of preference. Use whichever you feel more comfortable with, or whichever seems to provide a more natural phrasing for your argument.
Please do stick to short arguments, with just two or three premises (no more, no less). If giving a categorical argument, it is okay to have three premises if you wish, even though we’ve focused on 2-premise syllogisms in class.
A Challenge Worksheet
THE CHALLENGE:
ARGUMENT ABOUT YOUR RESPONSE TO THE CHALLENGE:
DEMONSTRATION THAT THE ARGUMENT IS VALID:
