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Session 2. Evidence, Opinion, Bias and Fallacies
Objective. Teach pupils to tell checkable facts, opinions and reasoned claims apart, to judge how strong a piece of evidence is, and to spot four or five common errors of reasoning in everyday talk.
Pupils hear claims all day: from adults, friends, adverts and phones. If the only tool they have is 'true or false', they will accept what sounds sure or what their family says. This session gives them a better question, 'How do you know?', and a small set of ways to weigh the answer. You are not teaching pupils to distrust everyone; you are teaching them to ask for reasons politely and to give their own.
Key ideas
Fact, opinion, or claim with reasons
- A fact can be checked ('Navruz is on 21 March'). An opinion is a taste or a value ('Plov is tastier than shashlik') and cannot be checked. A claim is a statement that others can accept or reject if you give reasons ('Our library should open on Saturday').
- Do not teach 'fact = true, opinion = false'. A fact can be wrong, and an opinion can be very well supported. The useful question is 'How do you know?'
- Give pupils one sentence frame: 'I think ..., because ..., I know this from ...'.
How strong is the evidence?
- Not all evidence weighs the same. Stronger: something we measured or saw ourselves, a textbook or an expert in the subject, several independent examples. Weaker: one story, 'everyone knows', 'my uncle says'.
- Three pupil questions: Is it relevant to the claim? Is there enough of it (one example or ten)? Who says so, and could they be wrong?
- Link to subjects: in science, an experiment; in history, two sources compared; in language, a quotation from the text.
Bias: in sources and in ourselves
- Bias is a lean that pushes thinking one way. A source can lean: a shop advertising its own pen, a poster for a school event. Ask: Who made this? What do they gain? What might they leave out?
- We lean too. We notice facts that agree with what we already think and skip those that do not. Teach the pupil question: 'What would change my mind?'
- Handle with care: say 'This writer leans toward ...' not 'This person lies'. Bias is not the same as lying, and everyone has some.
Five everyday fallacies
- A fallacy is a reasoning error that sounds convincing. Teach five with pupil names: 'Everyone says so' (bandwagon), 'Attack the person', 'One case proves all' (hasty generalisation), 'Only two choices' (either/or), 'After, so because' (post hoc).
- Use them to improve an argument, not to win a quarrel. The pupil move is: 'I see the problem: ... What would make it stronger?'
- Keep it to 2 or 3 fallacies at a time at primary level; secondary pupils can learn all five and look for them in adverts.
Three kinds of statement
Fact
Can be checked
- Navruz is on 21 March
- Check: calendar, textbook
Opinion
A taste or value
- Plov is tastier than shashlik
- Respond: respect, ask why
Claim
Needs reasons
- Our library should open on Saturday
- Ask: how do you know?
After does not mean because
Many weak arguments in school and at home rest on a pattern: two things happened together, so one caused the other. Marks rose after a new teacher came; a field gave more cotton after a new seed was used. Both may be true causes, but pupils should learn to ask: what else changed, and what happened in a similar case without the change?
This is a first step towards a fair test. In science, a pupil changes one thing and keeps the rest the same. In everyday talk, the habit is simply asking 'compared with what?'. Even Grade 4 pupils can answer: 'Compared with the class next door.'
When the weak argument is ours, or a family's
It is easy to find mistakes in other people's reasoning and hard to find our own. We tend to notice facts that agree with what we already believe. Teach pupils to look for one piece of evidence that could show they are wrong, and model it yourself: 'I thought homework helps everyone; let me check what the notebooks show.'
Some claims come from family or tradition, and a pupil may feel that questioning them is disloyal. Show that checking is a way of taking an idea seriously. 'Let us find out if the idea is right' respects the grandfather and also respects the evidence. Never ask a pupil to choose between the two.
Examples from the classroom
Sorting in Grade 5
Scene. Dilnoza teaches Grade 5 in Samarkand. She puts three cards on the board: 'The Registan is in Samarkand', 'The Registan is the most beautiful place', 'We should visit the Registan because we are studying the 15th century'. In pairs, pupils sort them into fact, opinion and claim in three minutes. Most agree on the first two. The third makes them ask what reason would convince the headteacher.
Insight. A claim is a statement that can be improved with reasons, which makes it different from a taste.
Which plot grew more?
Scene. Aziz teaches Grade 7 science in Tashkent. Two bean plots grew in the school yard, and pupils say 'plot A had more beans because we used the new fertiliser'. Aziz asks, 'What else was different?' The class finds that plot A also got more sun and was watered more often. They plan a second plot where only fertiliser changes.
Insight. Asking 'what else changed?' moves pupils from after-so-because to a fair comparison.
Everyone buys it
Scene. Malika teaches Grade 9 Russian-medium class in Fergana. For a media task, pupils bring adverts. One says 'Everyone in Uzbekistan uses this phone, join them!' Malika asks, 'Is that a reason to buy it for you?' Pupils write two lines: what the advert wants and what they would need to know about the phone. They find prices, battery life and repair costs matter more than 'everyone'.
Insight. Naming the bandwagon pattern helps pupils separate pressure from reasons.
Common pitfalls
- Teaching that facts are always true and opinions always worthless, so pupils stop thinking about both.
- Naming fallacies to win arguments or to embarrass a pupil.
- Teaching ten fallacy names so that pupils memorise labels but cannot use them.
- Treating a pupil's family source with scorn instead of curiosity.
Sort, Strengthen, Spot
- In pairs (10 min): sort the 12 statements in your Activity Kit into F (checkable fact), O (opinion) or C (claim that needs reasons). Mark any statement where you disagree with your partner and argue it.
- Choose two C statements. For each, write what evidence would make it stronger, and rate the evidence already given: strong, medium or weak (10 min).
- Read the five short dialogues. Name the fallacy in each, using the plain names, and write a one-sentence reply a pupil could say that is kind and clear (15 min).
- Alone (10 min): choose a topic from your own timetable and write the claim, reason and evidence pupils will practise; fill in your classroom action task.
Your facilitator will guide you through this activity in the session.
Questions to discuss
- Which statements caused disagreement, and what made them hard to sort?
- How would you teach the idea that an opinion can be well supported, to a Grade 4 class and to a Grade 9 class?
- When is it better not to name the fallacy and only ask 'How do you know?'
Reflect
- When did a pupil last give you an opinion as if it were a fact, and how did you respond?
- Which topic in your subject is ready for a 'claim, reason, evidence' paragraph?
- Which of your own opinions do you state as facts in class?
Try it tomorrow
- Write the frame 'I think ..., because ..., I know this from ...' on the board and ask every pupil for one sentence after your next reading.
- Pick one claim from your textbook that has weak evidence and ask the class, 'What would make this stronger?'
- Teach just two fallacies this week, with a pupil-friendly name and one example each.
Further reading and links
Ask 'How do you know?': separate fact, opinion and claim, weigh the evidence, notice the lean, and fix the argument instead of beating the person.