The big idea: Reason is one of our sources of knowledge — but reasoning comes in two very different flavours, and mixing them up causes real mistakes.
Certainty or a bet: One gives you certainty. The other only gives you a good bet — and a surprising amount of what we call knowledge rests on the second.
Deductive — certain
- General rule → a particular case
- 'All humans are mortal; Socrates is human; so Socrates is mortal'
- If the premises are true, the conclusion MUST be true
Inductive — probable
- Many cases → a general rule
- 'The sun rose every day so far; so it'll rise tomorrow'
- The premises make it LIKELY, never certain
Checkpoint — deduction vs induction: In one line: deduction goes general → particular and is certain; induction goes cases → rule and is only probable. Science and everyday life lean heavily on the probable kind.
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Induction feels rock-solid — until Hume asks one simple question about it.
Why should the future be like the past?: David Hume noticed that all inductive reasoning secretly assumes one thing: that the future will resemble the past.
How the circle works
The bet
The sun rose every day so far, so we bet it will tomorrow.
The assumption
That bet only works IF nature keeps behaving as it has.
The circle
How do we know it will? Only because it always has before — which is using induction to justify induction.
Bet · Assume · Circle
The problem of induction: Going in a circle like this is the problem of induction.
Go further — higher-level insight: Hume isn't telling you to stop trusting the sunrise. His point is deeper: induction can't be given a logical PROOF, yet we can't live without it. So maybe knowledge of the world was never about certainty at all — it's about reasonable, well-supported bets. Framing induction as 'rational belief without proof' is a top-band move.
Checkpoint — the problem of induction: In one line: induction can't be proven, because any proof would itself have to use induction — yet we can't do without it.
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One last question turns knowledge inward: is knowing your own mind surer than knowing the world?
The case for self-knowledge being special: There's an old thought that self-knowledge is the most certain knowledge of all. You might be wrong that it's raining, but surely you can't be wrong that you feel cold or seem to see red?
Why it seems so certain
- Your own inner states are right there
- No senses to fool you, no testimony to distrust
- Descartes leaned on exactly this: even doubting everything else, you can't doubt your own thinking
The pushback: you can be a stranger to yourself: But it's not that simple. You may have special access to the feeling of a moment, but real self-knowledge — understanding your own character and motives — can be as hard-won as knowledge of anything else.
How people get themselves wrong
- They are often wrong about WHY they did something
- They deceive themselves about what they really want
- They don't notice their own moods until a friend points them out
Checkpoint — self-knowledge: In one line: you may be certain of how you FEEL, but understanding your own character and motives can be as hard as knowing the world.
How Section B works: Section B is an ESSAY [25] on an optional theme like epistemology — NO stimulus, just a question you argue. The command is usually 'Evaluate' or 'Discuss'.
What you do in the essay
Pick
Pick the views.
Argue
Argue them.
Weigh
Weigh them against each other.
Conclude
Reach a reasoned conclusion — this whole topic feeds it.
Pick · Argue · Weigh · Conclude
Evaluate the claim that we can never have certain knowledge of the world.
Model answer plan
See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.
Common mistakes: 1. Describing views instead of arguing them. 2. Only one view — top bands need tension. 3. No conclusion — decide, with a reason. 4. Name-dropping — a name earns nothing without its argument. 5. Forgetting §B needs NO stimulus — just argue the question.