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Cameroon GCE A-Level Philosophy study materials
Cameroon GCE A-Level Philosophy study resources

Cameroon GCE A-Level Philosophy practice questions

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Question 1Logic and Critical Reasoning

In a categorical proposition of the form 'No S are P', what is the quantity and quality of the proposition?

  1. Particular and affirmative
  2. Particular and negative
  3. Universal and negative Correct answer.
  4. Universal and affirmative

Explanation

The word 'No' makes the proposition universal because it says something about the whole class S, and it is negative because it denies the predicate of that class. This is the standard E proposition of Aristotelian logic.

Question 2Logic and Critical Reasoning

A student argues: 'Either the school buys new laboratory equipment or it cannot teach chemistry practically. The school has not bought new equipment. Therefore it cannot teach chemistry practically.' Which valid argument form does this exemplify?

  1. Disjunctive syllogism Correct answer.
  2. Hypothetical syllogism
  3. Modus ponens
  4. Modus tollens

Explanation

The first premise is a disjunction, the second premise denies one disjunct, and the conclusion affirms the other. That structure is disjunctive syllogism, which is valid when the disjunction is exclusive or when one disjunct is eliminated.

Question 3Logic and Critical Reasoning

Which pair of terms is correctly described as contradictory opposition in the traditional square of opposition?

  1. Universal negative and particular affirmative
  2. Universal affirmative and particular negative Correct answer.
  3. Particular affirmative and particular negative
  4. Universal affirmative and universal negative

Explanation

Contradictories differ in both quantity and quality and cannot share the same truth value: if one is true the other is false. The A proposition and the O proposition form such a pair.

Question 4Logic and Critical Reasoning

Consider the argument: 'All committed debaters read widely. Some students who read widely are not committed debaters. Therefore some students are not committed debaters.' Which statement about its validity is correct?

  1. It is invalid because the middle term is not distributed in the first premise Correct answer.
  2. It is valid because the conclusion follows from the second premise alone
  3. It is valid by the rule of subalternation
  4. It is invalid because it has four terms

Explanation

The middle term 'read widely' is undistributed in both premises, so the syllogism commits the fallacy of the undistributed middle. The conclusion does not follow, even though it happens to be plausible.

Question 5Logic and Critical Reasoning

Which of the following best captures the logical meaning of a valid deductive argument?

  1. It is impossible for the premises to be true and the conclusion false Correct answer.
  2. The conclusion is accepted by most competent reasoners
  3. The premises are all true in the actual world
  4. The conclusion is more probable than its negation

Explanation

Validity concerns the necessary connection between premises and conclusion, not the actual truth of either. An argument is valid when no possible situation makes the premises true and the conclusion false.

Question 6Logic and Critical Reasoning

A candidate claims: 'Every great philosopher was misunderstood in his lifetime. Socrates was misunderstood in his lifetime. Therefore Socrates was a great philosopher.' Which fallacy does this argument commit?

  1. Begging the question
  2. Affirming the consequent Correct answer.
  3. Equivocation
  4. False cause

Explanation

The first premise has the form 'If great philosopher, then misunderstood'. The second premise affirms the consequent, and the conclusion affirms the antecedent, which is the classic fallacy of affirming the consequent.

Question 7Logic and Critical Reasoning

In propositional logic, which truth-functional connective yields a true compound proposition only when both of its component propositions are true?

  1. Biconditional
  2. Material implication
  3. Inclusive disjunction
  4. Conjunction Correct answer.

Explanation

A conjunction is true in exactly one case: when both conjuncts are true. Any false conjunct makes the whole conjunction false.

Question 8Logic and Critical Reasoning

A newspaper editorial states: 'The senator is either dishonest or incompetent. We have shown that he is not incompetent. Hence he is dishonest.' Which condition must hold for this argument to be formally valid?

  1. The second premise must be established by testimony
  2. The conclusion must be more general than the premises
  3. The senator must actually be dishonest
  4. The disjunction must be treated as exclusive Correct answer.

Explanation

Disjunctive syllogism is valid for exclusive disjunction and also for inclusive disjunction when one disjunct is denied. The option that states a genuine requirement for the standard reading is that the disjunction be exclusive, since otherwise the argument needs the additional denial to work.

Question 9Logic and Critical Reasoning

Which statement correctly describes the relationship between validity and soundness?

  1. A sound argument may have a false conclusion if its form is valid
  2. Every valid argument is sound, but not every sound argument is valid
  3. Validity and soundness are the same property under different names
  4. Every sound argument is valid, but not every valid argument is sound Correct answer.

Explanation

Soundness adds the requirement that all premises be true to the requirement of validity. Hence sound arguments form a subset of valid arguments, and a valid argument with a false premise is not sound.

Question 10Logic and Critical Reasoning

A teacher says: 'If you attend every seminar, you will pass. You did not pass. Therefore you did not attend every seminar.' Which inference rule justifies this conclusion?

  1. Modus tollens Correct answer.
  2. Addition
  3. Modus ponens
  4. Simplification

Explanation

The argument denies the consequent of a conditional and concludes the denial of the antecedent, which is modus tollens. This form is valid for material implication.

Question 11Logic and Critical Reasoning

Which of the following is an example of the fallacy of equivocation?

  1. 'Either you support the policy or you are against progress'
  2. 'You cannot prove I am wrong, so I must be right'
  3. 'Everyone believes it, so it must be true'
  4. 'All banks are financial institutions; the river has banks; so the river has financial institutions' Correct answer.

Explanation

Equivocation trades on a single word used in two different senses within one argument. Here 'bank' shifts from a financial institution to a riverbank, so the middle term is not genuinely the same term.

Question 12Logic and Critical Reasoning

In a categorical syllogism, a term is distributed when the proposition refers to the entire class denoted by that term. In which proposition is the predicate term distributed?

  1. Some artists are not insensitive people
  2. No artists are insensitive people Correct answer.
  3. All artists are sensitive people
  4. Some artists are sensitive people

Explanation

In universal negative propositions, both subject and predicate are distributed because the whole of each class is excluded from the other. The E proposition therefore distributes its predicate.

Question 13Logic and Critical Reasoning

A student writes: 'Either the government raises taxes or it reduces public spending. Raising taxes is unpopular. Therefore the government will reduce public spending.' Which criticism is most accurate?

  1. The argument is invalid because the second premise concerns popularity, not the denial of a disjunct Correct answer.
  2. The argument commits the fallacy of composition
  3. The argument begs the question
  4. The argument is valid but unsound because the first premise is false

Explanation

Disjunctive syllogism requires the denial of one disjunct. The premise that raising taxes is unpopular does not deny that taxes will be raised, so the disjunction is not eliminated and the conclusion does not follow.

Question 14Logic and Critical Reasoning

Which of these sentences expresses a proposition in the logical sense?

  1. Close the door, please
  2. The library closes at six o'clock Correct answer.
  3. Oh, for a quiet place to read
  4. Is the library open?

Explanation

A proposition is a declarative statement capable of being true or false. Only the declarative sentence about the library's closing time has a truth value.

Question 15Logic and Critical Reasoning

An arguer says: 'Professor Nkeng has won three teaching awards, so his claim that the new syllabus is unworkable must be correct.' Which fallacy is committed?

  1. Slippery slope
  2. Ad hominem
  3. Straw man
  4. Appeal to authority Correct answer.

Explanation

The argument treats the professor's standing as a teacher as sufficient evidence for a technical claim about the syllabus. Deference to authority is fallacious when the authority is not relevant to the specific issue.

Question 16Logic and Critical Reasoning

Which pair of propositions can both be false but cannot both be true?

  1. Subcontraries
  2. Contraries Correct answer.
  3. Subalterns
  4. Contradictories

Explanation

Contraries, such as the A and E propositions, cannot both be true, but they can both be false when the subject class is partly inside and partly outside the predicate class.

Question 17Logic and Critical Reasoning

Which of the following best explains why an inductive argument can be strong without being deductively valid?

  1. Its conclusion is a tautology
  2. Its premises make the conclusion probable rather than certain Correct answer.
  3. It contains no premises at all
  4. Its premises are always false in the actual world

Explanation

Inductive strength is a matter of the premises raising the likelihood of the conclusion without guaranteeing it. Deductive validity requires that the conclusion be impossible to falsify given true premises.

Question 18Logic and Critical Reasoning

A debater argues: 'We should not listen to his proposal on farming because he is a poor public speaker.' Which fallacy is committed?

  1. Appeal to pity
  2. False analogy
  3. Ad hominem Correct answer.
  4. Hasty generalization

Explanation

The argument attacks an irrelevant feature of the person, his speaking ability, instead of assessing the farming proposal itself. That is the circumstantial or abusive form of ad hominem.

Question 19Logic and Critical Reasoning

Which formal fallacy occurs in the argument 'If it rained, the ground is wet. The ground is wet. Therefore it rained'?

  1. Illicit minor
  2. Undistributed middle
  3. Denying the antecedent
  4. Affirming the consequent Correct answer.

Explanation

The second premise affirms the consequent of the conditional, and the conclusion affirms the antecedent. Other causes of wet ground make the conclusion uncertain, so the form is invalid.

Question 20Logic and Critical Reasoning

Which statement about the truth table for material implication is correct?

  1. It has the same truth table as conjunction
  2. It is false only when the antecedent is true and the consequent false Correct answer.
  3. It is true only when both components are true
  4. It is false only when both components are false

Explanation

Material implication has the value false in exactly one row: true antecedent with false consequent. In all other rows, including the case of a false antecedent, it is true.

Question 21Logic and Critical Reasoning

A speaker argues: 'Every student who joined the debate club improved in confidence. Marie improved in confidence. Therefore Marie joined the debate club.' Which criticism is most precise?

  1. The argument commits the fallacy of equivocation
  2. The argument is valid but has a false premise
  3. The argument affirms the consequent and so is invalid Correct answer.
  4. The argument is a sound categorical syllogism

Explanation

The first premise says joining implies improvement. The second premise affirms the improvement, and the conclusion affirms joining, which is affirming the consequent. Improvement could have other causes.

Question 22Logic and Critical Reasoning

Which of the following is the best example of a question-begging argument?

  1. 'Freedom of speech is valuable because unrestricted expression is a good thing' Correct answer.
  2. 'Either we invest in schools or we accept ignorance'
  3. 'My opponent is young, so his economic plan is wrong'
  4. 'Many people own cars, so everyone should own one'

Explanation

The premise restates the conclusion in different words, so the argument assumes what it sets out to prove. No independent support is offered for the value of free expression.

Question 23Logic and Critical Reasoning

In a syllogism, which rule is violated by an argument whose major term is distributed in the conclusion but undistributed in the major premise?

  1. The fallacy of the undistributed middle
  2. The fallacy of the illicit minor
  3. The fallacy of four terms
  4. The fallacy of the illicit major Correct answer.

Explanation

A term that is distributed in the conclusion must be distributed in its premise. When the major term breaks this rule, the syllogism commits the illicit major.

Question 24Logic and Critical Reasoning

A politician says: 'If we allow students to choose their subjects, soon they will choose no mathematics, then no science, and finally no education at all.' Which fallacy is most clearly illustrated?

  1. Circular reasoning
  2. False cause
  3. Appeal to authority
  4. Slippery slope Correct answer.

Explanation

The argument predicts an unchecked chain of increasingly extreme consequences without justifying each link. This is the slippery-slope pattern, which is fallacious when the causal chain is asserted rather than shown.

Question 25Logic and Critical Reasoning

Which statement correctly distinguishes a contradiction from a contingent proposition?

  1. A contradiction depends on empirical evidence, while a contingent proposition does not
  2. A contradiction is false in every possible situation, while a contingent proposition is true in some and false in others Correct answer.
  3. Both are false in every possible situation
  4. A contradiction is true in every possible situation, while a contingent proposition is always false

Explanation

A contradiction, such as 'It is raining and it is not raining', cannot be true under any assignment of truth values. A contingent proposition, such as 'It is raining', varies in truth value across situations.

Question 26Logic and Critical Reasoning

In critical reasoning, a statement is called 'cogent' when it is a strong inductive argument whose premises are all true. Which situation best fits that description?

  1. An argument in which the conclusion is repeated among the premises.
  2. A deductively valid argument whose premises are in fact true.
  3. A weak argument in which the conclusion happens to be true.
  4. A survey of 2,000 randomly chosen voters finds 68 per cent support a policy, and the premises reporting the sampling method and results are accurate. Correct answer.

Explanation

Cogency applies to inductive arguments: the argument must be strong, meaning the premises make the conclusion highly probable, and all its premises must actually be true. A well-conducted random sample with accurate reported results satisfies both conditions. Deductive correctness is assessed by validity and soundness, not cogency.

Question 27Logic and Critical Reasoning

A student reasons: 'If the library closes early, the reading room is locked. The reading room is locked. So the library closed early.' Which formal fallacy does this argument commit?

  1. Denying the antecedent
  2. False dilemma
  3. Affirming the consequent Correct answer.
  4. Undistributed middle

Explanation

The second premise affirms the consequent of the conditional rather than its antecedent, so the inference is invalid: the reading room could be locked for many other reasons. Affirming the consequent has the form 'If P then Q; Q; therefore P'. Denying the antecedent would instead use 'not P' to conclude 'not Q'.

Question 28Logic and Critical Reasoning

Consider two propositions: 'All civil servants are graduates' and 'Some civil servants are not graduates'. Which logical relation holds between them?

  1. They are contradictories, so exactly one must be true and the other false. Correct answer.
  2. They are subcontraries, so they can both be true but cannot both be false.
  3. They are contraries, so they cannot both be true but can both be false.
  4. They are subalterns, so the truth of the first guarantees the truth of the second.

Explanation

These are the A and O propositions of the traditional square of opposition, sharing the same subject and predicate but differing in quantity and quality. Contradictories always divide truth values: if the universal affirmative is true, the particular negative is false, and vice versa.

Question 29Logic and Critical Reasoning

A debater argues: 'Either the council builds the bridge this year or the town stays isolated. The council will not build the bridge this year. Therefore the town stays isolated.' Why is this argument deductively valid?

  1. It is valid because the first premise is a conditional statement.
  2. It is a disjunctive syllogism whose second premise denies one disjunct, leaving the other as the conclusion. Correct answer.
  3. It is valid because the conclusion is plausible given the premises.
  4. It is valid because the disjunction is exclusive rather than inclusive.

Explanation

The argument has the form 'P or Q; not P; therefore Q', which is the disjunctive syllogism, a valid inference pattern. Validity here depends on form, not on plausibility or on whether the disjunction is exclusive.

Question 30Logic and Critical Reasoning

A syllogism has the mood and figure AII-1: 'All teachers are graduates; some graduates are musicians; therefore some teachers are musicians.' Which defect explains why it is invalid?

  1. The conclusion is a universal proposition drawn from particular premises.
  2. The middle term 'graduates' is undistributed in both premises. Correct answer.
  3. The minor term is distributed in the conclusion but not in the premise.
  4. The argument has two negative premises.

Explanation

In AII-1 the middle term 'graduates' is the predicate of an A proposition and the subject of an I proposition, and neither distributes it. A middle term that is undistributed in both premises cannot link them, so the conclusion does not follow.

Question 31Epistemology

In epistemology, which tripartite analysis of knowledge is traditionally attributed to Plato's Theaetetus?

  1. Knowledge is perception, opinion, and calculation combined
  2. Knowledge is innate recollection of the Forms alone
  3. Knowledge is true belief accompanied by a rational account (justified true belief) Correct answer.
  4. Knowledge is any belief that produces successful action

Explanation

The standard reading of the Theaetetus presents knowledge as true belief plus a logos, giving the classic justified-true-belief formula. Perception and true opinion are each examined and rejected as sufficient on their own. This tripartite formula became the target of Gettier's later objections.

Question 32Epistemology

Gettier's 1963 counterexamples are designed to show which claim is false?

  1. Belief is a necessary condition of knowledge
  2. Truth is a necessary condition of knowledge
  3. Justified true belief is sufficient for knowledge Correct answer.
  4. Some propositions are known without justification

Explanation

Gettier constructs cases where a subject has justified true belief yet intuitively lacks knowledge, so sufficiency fails. He does not challenge the necessity of truth or belief. The cases turn on luck connecting justification and truth.

Question 33Epistemology

A farmer sees a sheep-shaped rock in a field and justifiably believes there is a sheep in the field; unknown to him, a real sheep is hidden behind the rock. Why is this a Gettier-style case?

  1. The farmer lacks any evidence for what he believes
  2. The belief is true and justified but its truth is only coincidental Correct answer.
  3. The farmer's belief is true but he has no justification
  4. The belief is false although the farmer is justified

Explanation

The farmer's evidence supports his belief and the belief happens to be true, yet the truth-maker is unrelated to his evidence. This accidental connection between justification and truth is what blocks knowledge. It mirrors the structure of Gettier's original examples.

Question 34Epistemology

According to the traditional JTB analysis, which condition is necessary but not sufficient for knowledge?

  1. Having a reliable memory of the proposition
  2. Being certain beyond any possible doubt
  3. Being justified in believing the proposition Correct answer.
  4. Being able to prove the proposition deductively

Explanation

Justification is required by the tripartite analysis but Gettier cases show it does not by itself secure knowledge. Deductive proof, reliable memory, and certainty are stronger or different conditions not demanded by the basic analysis. The point is that justification alone leaves a gap.

Question 35Epistemology

Which response to Gettier holds that knowledge requires the justification to be causally connected to the truth of the belief?

  1. The virtue reliabilist account
  2. The coherence theory of justification
  3. The causal theory of knowledge Correct answer.
  4. The contextualist account

Explanation

The causal theory, associated with Goldman, requires that the fact believed be appropriately causally linked to the belief. This rules out coincidental truth as in the sheep-rock case. Coherence, virtue reliabilism, and contextualism address different aspects of justification or standards.

Question 36Epistemology

A reliabilist about knowledge would say a true belief counts as knowledge when it is produced by:

  1. A cognitive process that reliably yields true beliefs Correct answer.
  2. A process the subject can fully justify to others
  3. A process the subject consciously controls step by step
  4. A process that coheres with the subject's other beliefs

Explanation

Reliabilism grounds knowledge in the truth-conduciveness of the belief-forming process rather than in the subject's access to reasons. This makes it an externalist position. Internalist justification, coherence, and conscious control describe rival accounts.

Question 37Epistemology

Internalism about epistemic justification characteristically holds that justifying factors must be:

  1. Cognitively accessible to the believing subject Correct answer.
  2. Socially recognized by the community
  3. Guaranteed to produce true beliefs
  4. External to the subject's mental states

Explanation

Internalism requires that whatever justifies a belief be available to the subject's reflective awareness. Externalism denies this accessibility requirement. Truth-guarantee and social recognition are distinct and stronger or different conditions.

Question 38Epistemology

Descartes' evil demon scenario is used in epistemology primarily to:

  1. Demonstrate the limits of the senses and motivate radical doubt Correct answer.
  2. Show that memory is always unreliable
  3. Prove that the external world does not exist
  4. Establish that God created the material world

Explanation

The demon hypothesis drives methodological doubt to its extreme, testing which beliefs survive. It is a device for isolating indubitable foundations, not a proof of scepticism's truth. Descartes ultimately uses it to motivate the cogito.

Question 39Epistemology

In Descartes' Meditations, what does the cogito establish?

  1. That clear and distinct ideas cannot be false
  2. That the external world is exactly as perceived
  3. That the doubting subject necessarily exists while doubting Correct answer.
  4. That the senses are generally reliable

Explanation

Even under the demon hypothesis, the act of doubting presupposes a doubter, so the subject's existence is indubitable. The cogito provides a foundation, not a proof of sensory reliability. The reliability of clear and distinct ideas is argued separately.

Question 40Epistemology

Hume's problem of induction challenges which inference?

  1. From premises to a conclusion by valid deduction
  2. From self-evident axioms to theorems
  3. From observed regularities to unobserved cases Correct answer.
  4. From testimony to the speaker's intentions

Explanation

Hume argues that projecting observed constant conjunctions onto future or unobserved cases lacks rational justification, since any defence would be circular. Deductive validity is not his target. The problem concerns the justification of inductive projection.

Question 41Epistemology

A coherentist about justification holds that a belief is justified when it:

  1. Fits consistently within a comprehensive system of beliefs Correct answer.
  2. Is held with maximum subjective confidence
  3. Is caused by the fact it represents
  4. Can be traced to sensory foundations

Explanation

Coherentism replaces foundational linear support with mutual support among beliefs in a system. Causal linkage belongs to the causal theory, confidence is not sufficient, and sensory foundations are foundationalist. Coherence is thus a holistic criterion.

Question 42Epistemology

Classical foundationalism in epistemology claims that justified beliefs ultimately rest on:

  1. Basic beliefs that do not depend on other beliefs for their justification Correct answer.
  2. The total coherence of the belief system
  3. The consensus of expert inquirers
  4. The reliability of the cognitive faculties alone

Explanation

Foundationalism posits non-inferential basic beliefs supporting the rest of the structure. Coherence is the rival holistic option, and faculty reliability is a reliabilist theme. Expert consensus is a social criterion.

Question 43Epistemology

The 'Münchhausen trilemma' as formulated by Albert is used to argue that foundational justification faces which three options?

  1. Coherence, correspondence, or pragmatism
  2. Deduction, induction, or abduction
  3. Empiricism, rationalism, or scepticism
  4. Infinite regress, circularity, or dogmatic stopping point Correct answer.

Explanation

Albert's trilemma claims any attempt to justify a belief ends in regress, circularity, or an arbitrary halt. This is deployed against classical foundationalism. The other triples name theories of truth, sources of knowledge, and inference types, not the regress problem.

Question 44Epistemology

Which position holds that knowledge attributions depend on the practical stakes of the attributor's context?

  1. Empiricism
  2. Classical invariantism
  3. Scepticism
  4. Epistemic contextualism Correct answer.

Explanation

Contextualism holds that the standards for 'knows' shift with context, including practical stakes. Invariantism denies such variation. Scepticism and empiricism concern doubt and the source of knowledge, not the semantics of attribution.

Question 45Epistemology

A student says: 'I know the exam is on Friday because my lecturer announced it, though I have not checked the timetable.' Which epistemic concept best describes the basis of her belief?

  1. Testimonial justification Correct answer.
  2. A priori justification
  3. Perceptual justification
  4. Introspective justification

Explanation

Reliance on a speaker's assertion for justification is testimonial justification. Perception, introspection, and a priori reasoning are distinct sources. The case illustrates how testimony functions as an epistemic source.

Question 46Epistemology

The 'problem of the criterion' as posed by Sextus Empiricus concerns:

  1. Whether truth is correspondence or coherence
  2. How testimony transmits knowledge
  3. How to justify a criterion of truth without already using it Correct answer.
  4. Whether memory can ever be trusted

Explanation

The problem asks whether one can validate a standard of judgment without circularly presupposing it. It generates the Agrippan modes and the regress of criteria. It is not a debate about theories of truth or memory.

Question 47Epistemology

In epistemology, a 'defeater' for a justified belief is:

  1. A belief that is true but unjustified
  2. Evidence or information that undermines the belief's justification Correct answer.
  3. Any proposition the subject believes
  4. A false belief held by the subject

Explanation

A defeater is something that weakens or cancels an existing justification, such as counter-evidence. It is not simply any belief or a true-but-unjustified belief. Defeaters explain how justification can be lost without changing the original evidence.

Question 48Epistemology

A person believes a proposition on the basis of evidence she has forgotten she once had. Her belief is true. Which description best fits the epistemic issue raised?

  1. Whether truth is necessary for knowledge
  2. Whether justification can be preserved without current access to the supporting evidence Correct answer.
  3. Whether testimony can ever justify
  4. Whether induction is rational

Explanation

The case probes whether past evidence can justify a present belief even when the subject no longer recalls it, a debate between access and non-access views. It does not concern truth's necessity, testimony, or induction. It illustrates the internalism/externalism divide over justification.

Question 49Epistemology

Which of these best states the 'no false lemmas' response to Gettier?

  1. Knowledge requires coherence with all other beliefs
  2. Knowledge requires that the belief not be inferred through any false intermediate step Correct answer.
  3. Knowledge requires certainty beyond doubt
  4. Knowledge requires a reliable cognitive faculty

Explanation

The no-false-lemmas condition blocks cases where a true belief is derived via a false premise. It is a direct amendment to the JTB analysis. Certainty, reliability, and coherence are separate theoretical additions.

Question 50Epistemology

A sceptic argues: 'You cannot rule out that you are dreaming, so you do not know you have hands.' Which principle does this argument rely on?

  1. Knowledge requires the ability to exclude relevant alternatives Correct answer.
  2. Knowledge is justified true belief
  3. Knowledge requires certainty of all logical consequences
  4. Knowledge is a reliable true belief

Explanation

The argument invokes a closure-style or relevant-alternatives principle: if you cannot exclude a possibility incompatible with your claim, you cannot know. It does not depend on the JTB formula or on reliabilism. The dreaming hypothesis functions as an unexcluded alternative.