Thank you for completing the challenge on crafting deductive arguments. Here are your solutions and some mastery secrets from us.
1. Which of these statements is true?
“A deductive argument leads to a conclusion which is absolute, or certain.” This statement is true.
In fact, some of our clients map their ideas out deductively to check whether their logic stacks up before they decide how to communicate to their audience. Quite often they find that they communicate inductively but with more confidence knowing that their logic is robust having mapped the story out deductively as a test.
2. Which of the following is true of the Statement?
All of the above. The Statement, or major premise of the argument, must be irrefutable, and new to the audience. You will support it with proof, usually arranged in a grouping structure.
3. How many ideas should you have at the key line in a deductive argument?
Usually three, occasionally four. Longer deductive chains are useful in problem solving – they can be as long as you like when used for this purpose. However, long deductive chains are awfully hard for a reader to follow, as they require the reader to absorb a lot of information before they get to the big idea. They are also logically risky as there are more links that might break. Therefore, we recommend sticking to only three key-line ideas within a deductive storyline.
4. The conclusion or ‘therefore' point at the right side of your deductive chain must be …
All of the above. It must be the only possible conclusion, and it must be a recommendation (not a reason) supported by actions. By the time you are revealing your conclusion to your audience, you will have already persuaded them that it is right and they will be ready to hear how you plan to implement it. You should not need further reasons at this stage. If you still need to persuade at this point, you need to revisit your logic.
5. A deductive argument must be …
Correct in both form AND fact. If either one of these is out of line then the whole structure will break and you will have created what we call a ‘flawed deductive argument'. The breaks can be subtle, so be careful: it is very easy to create a flawed argument that seems quite powerful until you really unpick it. For the deductive argument to be correct in form, the statement must be true, and the comment must be linked to the statement in such a way that together they lead inevitably to the conclusion. To be true in fact, your deductive argument must have the proof that proves the statement and the proof that proves the comment, and actions to support the conclusion.
6. Groupings of ideas support each premise within a deductive argument
True. The support for each part of the deductive storyline will be arranged as a grouping. Usually it means a grouping of reasons that support the major premise (although sometimes they may be examples), a grouping of reasons to support the minor premise (or examples) and then a grouping of actions to support the recommendation (or conclusion).
7. Deductive arguments are powerful when the logic is tight, but otherwise risky. Why?
All of these points are correct:
8. The Answer (or Governing Idea) should be EXACTLY the same as the Conclusion, or “Therefore” point
False. The Governing Idea should be the synthesis of the whole story, which means that it must synthesise both the reasons why your conclusion is valid, and the conclusion itself. For example, not just “Take steps to fix X” but “ABC should take steps to fix X to turn around poor performance”
9. The Answer (or Governing Idea) that overarches a deductive story must include …
Your recommendation AND the reasons supporting it. A deductive argument includes both your recommendation and the reasons for it and the Answer must synthesise the whole argument, which means that it must speak to both of these things.
10. The conclusion at the right side of your deductive chain must only be supported by …
Actions. By the time you are revealing your conclusion to your audience, you will have already persuaded them that it is right and they will be ready to hear how you plan to implement it. You should not need further reasons at this stage. If you still need to persuade at this point, you need to revisit your logic.
Do let us know if you have questions about any of these by emailing us at firstname.lastname@example.org
Davina and Gerard