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Week 3 · Assignment: Traditional alternative (no AI)

Week 3 — Guarantee or Good Bet: Testing Deductive and Inductive Links — Traditional alternative (no AI)

Critical Thinking Free sample edition
Traditional alternative (no AI), unpublished. In the course this is a separate assignment that ships unpublished beside the adaptive assignment: same objective, no AI. An instructor who prefers it publishes it and unpublishes or deletes the adaptive one, as the note at its top says.

Instructors: publish this instead of the adaptive version if you prefer, and unpublish or delete the adaptive one.

Assignment 3 of the term — sort each link by what it promises, test it with the tool that fits, and explain the difference between proof and a good bet to someone new to the subject.

This week you learned to sort an argument as deductive or inductive, to test a deductive link for validity and soundness with the counterexample method, and to rate an inductive link's strength and say when it is cogent. In this assignment you work four short problems on two illustrative texts, interpret each one, and explain the difference between proof and a good bet to someone who has never studied critical thinking. This week's lecture tutorial, quiz, discussion, and Argument Workshop practise the same ideas from other angles.

The task

Your first text is the running question's illustrative campus-newsletter argument, which has no real author: "The campus library should stay open around the clock during finals week. During finals week many students need a quiet, safe place to study late at night. The library is the only quiet, safe, well-lit study space on campus large enough to meet that need. Keeping the library open overnight for the five nights of finals week costs about 1,600 dollars in staff wages." In standard form it has P1, P2, P3 (supplied: "The campus should provide study space students need during finals when it can do so at modest cost"), P4, and C. Its map has 2 support links: P1, P2, and P3 work together to support C, and P4 supports P3's "modest cost" condition. The cost condition is the claim "Keeping the library open overnight during finals week costs a modest amount."

Your second text is an illustrative note from an apartment building's front desk, with no real building behind it: "Of the last 20 packages marked delivered for the third floor, 18 were found on the lobby shelf." Below the note, a resident reasons: "My package was marked delivered this morning, so it is on the lobby shelf."

Work these four problems, showing your arithmetic and quoting the sentences you use:

  1. The running question's P4 says overnight staffing costs 1,600 dollars for 5 nights. What does it cost a night, in dollars?
  2. P4's staffing plan assumes 2 staff working 8 hours a night for 5 nights. How many staff hours is that in all?
  3. The front-desk log says 18 of the last 20 packages marked delivered were found on the lobby shelf. What percentage of those packages were found on the shelf?
  4. Of the same 20 logged packages, how many were not found on the lobby shelf?

Beside each answer, add one brief interpretation:

  • Problem 1: say which link in the running question's map the cost a night bears on, and explain why the link from P4 to the cost condition is inductive by describing one case in which P4 is true while "the cost is modest" is false.
  • Problem 2: show that the link from P1, P2, and P3 to C is not valid as it stands by describing a case in which those three premises are true and C is false, then explain why the link is valid once the cost condition is granted.
  • Problem 3: sort the resident's argument as deductive or inductive from its wording, say how strong it is in degrees, and say what would make it cogent.
  • Problem 4: explain why the packages not found on the shelf show that the resident's argument is not valid, then write the message to the resident's roommate described below.

Explain it to a non-expert

The resident's roommate has never studied logic and asks, "The log shows almost every package ends up on the shelf. Doesn't that prove this one is down there?" Write a 3–5 sentence message that explains in everyday words the difference between an argument that guarantees its conclusion and one that only makes it likely, reports the percentage you found and how many packages were not on the shelf, and names one limit: even a strong argument with true premises can be wrong this time. Explain any technical term in everyday words. More than one good answer is possible.

For a different, ungraded example, imagine a coworker reading a weather app that says rain is likely this afternoon. Model answer: "The app is making a good bet, not a promise. Its reasons make rain likely, so taking an umbrella is sensible, but nothing about a forecast rules out a dry afternoon. If it stays dry, the forecast was not illogical; it was a strong argument that missed this time."

Use that pattern for the roommate, with your own wording and evidence.

Show your arithmetic and quote the sentences you use. A reader should be able to reproduce every number you report, and find every quoted sentence in the argument or the note, without guessing which values, steps, or sentences you used.

Deliverables

Submit a single report containing:

  • the four answers, each with the arithmetic shown and the brief interpretation the task names for that problem;
  • your message to the roommate, explaining the difference between guaranteeing and making likely, reporting the percentage and how many packages were not on the shelf, and naming one limit; and
  • a one-line restatement of the values you used (the cost and the nights, the staffing inputs, and the logged and shelved package counts), so your answers are reproducible.

Keep it to roughly one page. Clear and correct beats long.

Choose how you show it. Present your report as written text, or as a recorded audio or video explanation of about three minutes with a transcript, or as a labelled sketch of the running question's map with each link marked deductive or inductive and a short note that says the map in words. Every form is graded by the same scoring criteria. Submit in any accessible file type or as a link; a recorded response may be submitted as audio or video with a transcript, or as text.

How you'll be graded

The full analytic rubric is attached to this assignment in Canvas.

Academic integrity and AI use

This version is designed to be completed without AI: do the computations, the interpretations, and the writing yourself, without a chatbot or other AI tool. Quote the argument and the note only as they are printed here, word for word. Submitting AI-generated work as your own, or copying another student's work, is an integrity violation under the course policy.

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