Grade a claim
I can assign one of the Academy's five statuses to a claim, name the kind of evidence behind it, and say what finding would change the label.
- Round IGrade a claim (this page)
- Round IIWeigh rival explanationsComing
- Round IIICalibrate your confidenceComing
1 Learn
You will be able to
- Explain the five statuses in your own words, with one example of each.
- Place a study finding on the ladder of evidence and state what it cannot show.
- Tell proof, evidence, authority and persuasion apart.
- Name which of Peirce's four methods produced a belief.
- LabThe five statusesThe five statuses for holding a claim, and the four grades for quotations.
- LibraryReading Nutrition Evidence: What a Study Can and Cannot Show · The ladder of evidenceA four-rung teaching ladder from mechanisms to clinical trials.2 min glance · 4 min
- LibraryReading Nutrition Evidence: What a Study Can and Cannot Show · A checklist for any claimSeven questions to put to any claim before you grade it.2 min glance · 4 min
- LibraryPeirce on the Fixation of Belief · The four methodsTenacity, authority, the a priori method and science, and the weakness of each.2 min glance · 4 min
- LibraryHypotheses, Predictions and Tests · Popper and falsificationWhy a claim must be open to refutation by observation.2 min glance · 6 min
- LibraryThe Seven Liberal Arts, Hands-On: Logic, Proof and the Quadrivium · Telling kinds of claim apartProof, evidence, inference, analogy, rhetoric and propaganda are different things.2 min glance · 7 min
- LabDefinitionsWarrant versus confidence, and proof versus evidence, persuasion and authority.
- LabThe ElenchusA worked example of one claim that carries two verdicts.
2 Practise
Answer each card from memory, then grade yourself honestly. The cards join your review deck and come back just before you would forget them.
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recall
In the Academy's five labels for holding a claim, what does "Demonstrated" mean?
Show answer
It follows by valid proof from premises stated in the open, so it can only fall if one of those premises falls.
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recall
What does the claim label "Aporetic" mean, and what does the Greek word aporia mean?
Show answer
Aporetic means genuinely unresolved. Aporia is Greek for "no way through", and saying a claim is aporetic is a result, not a failure.
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apply
A claim has survived repeated measurement and attempts to break it, and could in principle be overturned, though you should bet on it. Which of the five claim labels fits?
Show answer
Established. It differs from Demonstrated, which follows by valid proof from open premises and can only fall if a premise falls.
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recall
In the blueberry trial described on this page, what was the primary outcome, and did it improve?
Show answer
The primary outcome was insulin resistance, and it did not improve. Some vascular and lipid measures did, but secondary positives do not erase a null primary result, because testing many outcomes makes some chance findings likely.
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recall
Name the four rungs of the page's teaching ladder of evidence, from lowest to highest.
Show answer
First, test-tube and animal experiments (mechanisms). Second, short-term biomarkers in people, such as blood pressure, glucose or cholesterol. Third, observational links between diet and outcomes in populations. Fourth, randomised trials of clinical events such as heart attacks, fractures and deaths.
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explain
Why can the Portfolio, DASH and PREDIMED trials not be used to rank single foods?
Show answer
They changed several foods together. That shows eating patterns can help, but it cannot reveal which ingredient did the work, so the results cannot say that one single food is better than another.
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apply
A headline says a spice extract slowed the growth of cells in a lab dish, so you should sprinkle more of the spice on dinner. Using this page's reasoning, what is wrong with that jump?
Show answer
The finding sits on the lowest rung: an extract in cell culture shows a possible mechanism, not an outcome in people. A sprinkle of spice in a meal is also a different dose, form and matrix, so the result does not transfer to the culinary level without a trial at that level.
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recall
What are Peirce's four methods of settling belief, and how does each one work?
Show answer
Tenacity (cling to a view and avoid anything that challenges it), authority (a state or institution fixes doctrine and suppresses dissent), the a priori method (adopt what is agreeable to reason), and science (let belief be caused by something independent of what we think).
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apply
A friend is sure one route to work is faster. He has never timed either route and changes the subject whenever someone disagrees. Which of Peirce's methods is he using, why does Peirce think it will not hold, and what would the method of science have him do?
Show answer
Tenacity: clinging to a view and avoiding challenges. Peirce argues the social impulse undermines it, because meeting people who think differently brings doubt back. The method of science would have him let something independent of his opinion decide, such as predicting the times and then timing both routes.
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recall
What is a warrant, and how does it differ from confidence?
Show answer
A warrant is whatever makes a true belief more than luck: the reason you would offer a stranger who asked why you are entitled to it. Confidence is only a feeling, and you can be sincerely certain yet wholly unwarranted.
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apply
An argument convinces people only because of who presents it, and stops working when the presenter's name is removed. By the Academy's test, is it a proof, and if not, what is it?
Show answer
No, it is rhetoric. A proof is a chain of steps each checkable by a stranger who does not trust you, so it still works with your name removed.
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explain
The claim that twelve-tone equal temperament cannot produce a pure perfect fifth is given two verdicts, Demonstrated and Provisional. Why two?
Show answer
The mathematics is Demonstrated: an irrational ratio cannot equal 3:2. Whether a 1.955-cent gap matters musically stays Provisional, because two cents is near the limit of pitch discrimination, yet the two fifths beat audibly when sustained. Both verdicts are recorded and neither is hidden.
3 Prove it: the mastery check
5 questions drawn from a pool of 12. The pass mark is 80%. There is no time limit, and you can retake it with new questions; your best result counts.
4 Prove it: the performance task
Grade five claims
Collect five claims from five different kinds of source, for example a textbook, a news headline about health, a technical manual, a proverb and a forum post. Leave out names and any personal details of the people involved. For each claim: (1) write it as one sentence that could be wrong; (2) choose one of the five statuses; (3) name the kind of evidence actually behind it (proof, randomised trial, observational study, mechanism, authority or none), and for a health or science claim say which rung of the ladder of evidence it sits on; (4) write one finding or observation that would change its status; (5) write one thing the evidence cannot show. Use at least three different statuses across the five. Allow 40 to 60 minutes.
What to hand in: A table of five rows with the columns claim, status, kind of evidence, what would change it, and what the evidence cannot show. Save it on the page or download it.
Saved only in this browser. To keep a copy, download it or export your progress.
5 Discuss: the seminar
Read the text, then think, write or talk through the question with someone. There is no answer key: the aim is a better question.
Logic or dialectic · Round 1
- Plato, Euthyphro, 2a-16a (the whole dialogue)Read the whole dialogue in one sitting. Give most attention to 5d-6e (Socrates asks for the one form that makes every pious act pious), 10a-11b (is the pious loved by the gods because it is pious?) and 15c-16a (the ending). The link is H. N. Fowler's translation on Perseus, which renders the key word (hosion) as 'holy'; many other translations say 'pious'. Benjamin Jowett's translation is also free at Project Gutenberg (ebook 1642).
Euthyphro is certain he knows what piety is, yet each answer he gives fails under Socrates' questions. What does the questioning accomplish, and would you call the ending a failure?
- At 6d-e Socrates asks for the one form that makes every pious act pious, not a list of pious acts. Why is a list of examples not a definition?
- At 10a Socrates asks whether the gods love the pious because it is pious, or whether it is pious because they love it. Why does the order of the explanation matter for the definition?
- At 11b-d Euthyphro complains that whatever they propose moves about and will not stay where they put it, and each speaker suggests the other is the Daedalus who sets it moving. Whose fault is it: the definitions', the speaker's or the questioner's?
Where logic is used
- LibraryEvidence-Based Troubleshooting: Separating ExplanationsEach drill asks what an observation really establishes before you choose the next test.2 min glance · 6 min
- LibraryReading Nutrition Evidence: What a Study Can and Cannot ShowPlace a health claim on the ladder of evidence and say what the study cannot show.2 min glance · 4 min
- LibraryTechnical Writing as ReasoningWrite a recommendation so that observation, inference and assumption stay visibly separate.2 min glance · 5 min
Self-administered checks and self-assessed tasks: no credential is awarded. The design borrows from Khan Academy (mastery levels), WGU (competencies proved by assessment) and St. John's College (seminars on primary texts); this site is not affiliated with any of them.