← IGCSE Computer Science Paper 1

AI characteristic: the ability to reason

An AI system reasons when it applies its rules to its data to work out a new conclusion that was not stored directly, instead of just looking up a saved answer.

Part of: IGCSE Computer Science 0478 — 6.3 Artificial Intelligence — Module 5

Understanding AI characteristic: the ability to reason in IGCSE Computer Science Paper 1

What it does: The conclusion from rule 1 (slippery) is used as a fact in rule 2, so the system chains its reasoning step by step. The facts (age and ticket) are combined by the rule to work out the price type, which was not stored directly. Reasoning means working out a new conclusion. Finding a saved answer is only a lookup. Reasoning applies rules to data (facts). Input and output devices are not part of the reasoning itself. Combining facts and rules gives a new conclusion. The robin fact was never stored, so the AI had to reason it out. The AI checks the data against the rule and works out the conclusion. That is the ability to reason.

Common mistakes: The conclusion just copies the stored fact. Reasoning means applying the rule to the fact to get a new conclusion, so it should be conclusion ← "Roads are wet". In this pseudocode, assignment uses ←, and = is a comparison. The fact must be stored with age ← 15 so the rule can use it.

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Learning

Duo

A medical AI has the rule 'IF fever AND rash THEN measles likely' and a patient's data shows fever and rash. It concludes measles is likely. What is this?

Looking up a stored answerReasoning: it applied a rule to data

Matches

A system reasons whenever it prints a saved answer from its data

↓

Printing a saved answer is only a lookup. Reasoning means using rules on data to work out a new conclusion.

Applying

Meanings

Term

reasoning

Meaning

An AI system reasons when it applies its rules to its data to work out a new conclusion that was not stored directly, instead of just looking up a saved answer.

Practice

fact ← temperature > 38

Testing

Gaps

fever AND cough THEN flu

Check Answer

Spots

3IF fact = "It is raining" THEN

4 conclusion ← "It is raining"

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Quick Questions

1. A medical AI has the rule 'IF fever AND rash THEN measles likely' and a patient's data shows fever and rash. It concludes measles is likely. What is this?

A. Looking up a stored answer

B. Reasoning: it applied a rule to data ✓

The AI combined the patient's data with a rule to work out a conclusion. Nobody stored 'this patient has measles' in advance.

2. Which system is reasoning?

A. A system that finds a saved answer in a table and displays it

B. A system that uses rules and facts to work out an answer it was never given ✓

Reasoning means working out a new conclusion. Finding a saved answer is only a lookup.

3. Which two things does an AI system combine when it reasons?

A. Its rules and its data ✓

B. Its screen and its keyboard

Reasoning applies rules to data (facts). Input and output devices are not part of the reasoning itself.

4. An AI knows: 'All birds have feathers' and 'A robin is a bird'. It concludes 'A robin has feathers'. Is the conclusion new?

A. Yes: it was worked out from two facts, not stored directly ✓

B. No: the answer was already stored word for word

Combining facts and rules gives a new conclusion. The robin fact was never stored, so the AI had to reason it out.

5. A program stores the line 'Capital of France = Paris' and prints it when asked. Is this reasoning?

A. No: it only looks up a stored answer ✓

B. Yes: it uses data to give an answer

Reasoning needs rules to work out a conclusion. Simply returning a saved fact is a lookup, not reasoning.

Match the Pairs

IF fever = TRUE AND rash = TRUE THEN diagnosis ← "measles" → A rule that combines two facts to reach a conclusion

answer ← LOOKUP(savedAnswers, question) → Looking up a stored answer, which is not reasoning

Reasoning step by step: the first conclusion becomes a new fact for the next rule → IF wet = TRUE THEN slippery ← TRUE IF slippery = TRUE THEN warning ← TRUE

Combining facts and rules reaches a new conclusion that was never stored → IF age < 18 AND ticket = TRUE THEN price ← "child"

A system reasons whenever it prints a saved answer from its data → Printing a saved answer is only a lookup. Reasoning means using rules on data to work out a new conclusion.

IF rain = TRUE THEN umbrella ← TRUE (the rule is never applied to any facts) → A rule on its own is not reasoning. The system must use the rule on its data (such as rain = TRUE) to reach a conclusion.

Key Term

reasoning

An AI system reasons when it applies its rules to its data to work out a new conclusion that was not stored directly, instead of just looking up a saved answer.

Fill in the Blanks

1. IF fever AND cough THEN flu

Hint: Type the keyword that starts a rule and checks its condition.

2. IF fever AND cough THEN flu

Hint: Type the operator that combines two facts so that both must be true.

3. IF fever AND cough THEN flu

Hint: Type the keyword that introduces the new conclusion the rule reaches.

4. IF cat THEN mammal ← TRUE IF mammal THEN animal ← TRUE OUTPUT animal

Hint: Type the variable concluded in step one that now acts as a fact in step two.

5. fever ← TRUE cough ← TRUE IF fever AND cough THEN flu ← TRUE

Hint: Type the assignment symbol that stores the new conclusion reasoned from the facts.

Spot the Error

Question 1

A fact ← "It is raining"

B rule ← "Rain makes roads wet"

C IF fact = "It is raining" THEN

D conclusion ← "It is raining"

E ENDIF

Line D — The conclusion just copies the stored fact. Reasoning means applying the rule to the fact to get a new conclusion, so it should be conclusion ← "Roads are wet".

Question 2

A age = 15

B IF age < 18 THEN

C status ← "minor"

D ENDIF

Line A — In this pseudocode, assignment uses ←, and = is a comparison. The fact must be stored with age ← 15 so the rule can use it.

Question 3

A fever ← TRUE

B cough ← TRUE

C IF fever OR cough THEN

D OUTPUT "Possible flu"

E ENDIF

Line C — The rule combines two facts, so both must be true. OR would fire with only one fact. It should be IF fever AND cough THEN.

Question 4

A isBird ← FALSE

B IF isBird THEN

C hasWings ← TRUE

D ENDIF

E OUTPUT hasWings

Line A — The starting fact is FALSE, so the rule never fires and no new conclusion is reached. The fact should be isBird ← TRUE.

Question 5

A mark ← 72

B IF mark = 70 THEN

C grade ← "A"

D ENDIF

E OUTPUT grade

Line B — The rule only matches a mark of exactly 70, so the fact 72 would not give a conclusion. It should be IF mark >= 70 THEN.

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