Combining Philosophers

All the ideas for Porphyry, Sextus Empiricus and A.J. Ayer

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180 ideas

1. Philosophy / D. Nature of Philosophy / 3. Philosophy Defined
Philosophy is a department of logic [Ayer]
1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / b. Philosophy as transcendent
Philosophy has its own mode of death, by separating soul from body [Porphyry]
1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / e. Philosophy as reason
Philosophers should abandon speculation, as philosophy is wholly critical [Ayer]
1. Philosophy / E. Nature of Metaphysics / 7. Against Metaphysics
Humeans rejected the a priori synthetic, and so rejected even Kantian metaphysics [Ayer, by Macdonald,C]
1. Philosophy / F. Analytic Philosophy / 2. Analysis by Division
You cannot divide anything into many parts, because after the first division you are no longer dividing the original [Sext.Empiricus]
1. Philosophy / F. Analytic Philosophy / 5. Linguistic Analysis
Ordinary speech is not exact about what is true; we say we are digging a well before the well exists [Sext.Empiricus]
1. Philosophy / F. Analytic Philosophy / 7. Limitations of Analysis
Critics say analysis can only show the parts, and not their distinctive configuration [Ayer]
1. Philosophy / G. Scientific Philosophy / 3. Scientism
Philosophy deals with the questions that scientists do not wish to handle [Ayer]
2. Reason / A. Nature of Reason / 9. Limits of Reason
Reasoning is impossible without a preconception [Sext.Empiricus]
2. Reason / E. Argument / 3. Analogy
You can't infer that because you have a hidden birth-mark, everybody else does [Ayer]
2. Reason / E. Argument / 6. Conclusive Proof
Proof moves from agreed premises to a non-evident inference [Sext.Empiricus]
2. Reason / F. Fallacies / 1. Fallacy
Induction assumes some uniformity in nature, or that in some respects the future is like the past [Ayer]
3. Truth / A. Truth Problems / 5. Truth Bearers
It is only when we say a proposition that we speak truly or falsely [Sext.Empiricus]
3. Truth / H. Deflationary Truth / 2. Deflationary Truth
We cannot analyse the concept of 'truth', because it is simply a mark that a sentence is asserted [Ayer]
5. Theory of Logic / B. Logical Consequence / 8. Material Implication
A valid hypothetical syllogism is 'that which does not begin with a truth and end with a falsehood' [Sext.Empiricus]
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
'Man is a rational mortal animal' is equivalent to 'if something is a man, that thing is a rational mortal animal' [Sext.Empiricus]
5. Theory of Logic / L. Paradox / 7. Paradoxes of Time
Since Socrates either died when he was alive (a contradiction) or died when he was dead (meaningless), he didn't die [Sext.Empiricus]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / a. Early logicism
Maths and logic are true universally because they are analytic or tautological [Ayer]
7. Existence / D. Theories of Reality / 1. Ontologies
Positivists regard ontology as either meaningless or stipulated [Ayer, by Robinson,H]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / b. Commitment of quantifiers
It is currently held that quantifying over something implies belief in its existence [Ayer]
8. Modes of Existence / C. Powers and Dispositions / 2. Powers as Basic
The presence of the incorporeal is only known by certain kinds of disposition [Porphyry]
8. Modes of Existence / D. Universals / 1. Universals
Are genera and species real or conceptual? bodies or incorporeal? in sensibles or separate from them? [Porphyry]
9. Objects / B. Unity of Objects / 1. Unifying an Object / a. Intrinsic unification
Diversity arises from the power of unity [Porphyry]
9. Objects / C. Structure of Objects / 8. Parts of Objects / c. Wholes from parts
Parts are not parts if their whole is nothing more than the parts [Sext.Empiricus]
9. Objects / D. Essence of Objects / 3. Individual Essences
We see properties necessary for a kind (in the definition), but not for an individual [Ayer]
9. Objects / D. Essence of Objects / 9. Essence and Properties
Some properties are inseparable from a thing, such as the length, breadth and depth of a body [Sext.Empiricus]
11. Knowledge Aims / B. Certain Knowledge / 1. Certainty
Only tautologies can be certain; other propositions can only be probable [Ayer]
11. Knowledge Aims / B. Certain Knowledge / 2. Common Sense Certainty
If an argument has an absurd conclusion, we should not assent to the absurdity, but avoid the absurd argument [Sext.Empiricus]
11. Knowledge Aims / B. Certain Knowledge / 5. Cogito Critique
Knowing I exist reveals nothing at all about my nature [Ayer]
To say 'I am not thinking' must be false, but it might have been true, so it isn't self-contradictory [Ayer]
'I know I exist' has no counterevidence, so it may be meaningless [Ayer]
11. Knowledge Aims / C. Knowing Reality / 1. Perceptual Realism / c. Representative realism
Whether honey is essentially sweet may be doubted, as it is a matter of judgement rather than appearance [Sext.Empiricus]
11. Knowledge Aims / C. Knowing Reality / 2. Phenomenalism
Logical positivists could never give the sense-data equivalent of 'there is a table next door' [Robinson,H on Ayer]
Material things are constructions from actual and possible occurrences of sense-contents [Ayer]
No one has defended translational phenomenalism since Ayer in 1940 [Ayer, by Kim]
Modern phenomenalism holds that objects are logical constructions out of sense-data [Ayer]
12. Knowledge Sources / A. A Priori Knowledge / 4. A Priori as Necessities
We could verify 'a thing can't be in two places at once' by destroying one of the things [Ierubino on Ayer]
12. Knowledge Sources / A. A Priori Knowledge / 5. A Priori Synthetic
Whether geometry can be applied to reality is an empirical question outside of geometry [Ayer]
12. Knowledge Sources / A. A Priori Knowledge / 7. A Priori from Convention
By changing definitions we could make 'a thing can't be in two places at once' a contradiction [Ayer]
12. Knowledge Sources / A. A Priori Knowledge / 8. A Priori as Analytic
To say that a proposition is true a priori is to say that it is a tautology [Ayer]
12. Knowledge Sources / B. Perception / 4. Sense Data / a. Sense-data theory
The concept of sense-data allows us to discuss appearances without worrying about reality [Ayer]
Positivists prefer sense-data to objects, because the vocabulary covers both illusions and perceptions [Ayer, by Robinson,H]
12. Knowledge Sources / B. Perception / 5. Interpretation
How can the intellect know if sensation is reliable if it doesn't directly see external objects? [Sext.Empiricus]
12. Knowledge Sources / B. Perception / 7. Causal Perception
Causal and representative theories of perception are wrong as they refer to unobservables [Ayer]
12. Knowledge Sources / C. Rationalism / 1. Rationalism
Some say motion is perceived by sense, but others say it is by intellect [Sext.Empiricus]
The main claim of rationalism is that thought is an independent source of knowledge [Ayer]
12. Knowledge Sources / D. Empiricism / 1. Empiricism
Empiricism lacked a decent account of the a priori, until Ayer said it was entirely analytic [O'Grady on Ayer]
All propositions (especially 'metaphysics') must begin with the senses [Ayer]
My empiricism logically distinguishes analytic and synthetic propositions, and metaphysical verbiage [Ayer]
12. Knowledge Sources / D. Empiricism / 3. Pragmatism
We distinguish ambiguities by seeing what is useful [Sext.Empiricus]
12. Knowledge Sources / D. Empiricism / 4. Pro-Empiricism
It is further sense-experience which informs us of the mistakes that arise out of sense-experience [Ayer]
12. Knowledge Sources / D. Empiricism / 5. Empiricism Critique
Empiricism, it is said, cannot account for our knowledge of necessary truths [Ayer]
12. Knowledge Sources / E. Direct Knowledge / 4. Memory
Memory is not conserved images, but reproduction of previous thought [Porphyry]
13. Knowledge Criteria / A. Justification Problems / 1. Justification / b. Need for justification
Fools, infants and madmen may speak truly, but do not know [Sext.Empiricus]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / b. Basic beliefs
Some things are their own criterion, such as straightness, a set of scales, or light [Sext.Empiricus]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / c. Empirical foundations
Basic propositions refer to a single experience, are incorrigible, and conclusively verifiable [Ayer]
13. Knowledge Criteria / C. External Justification / 3. Reliabilism / a. Reliable knowledge
Madmen are reliable reporters of what appears to them [Sext.Empiricus]
13. Knowledge Criteria / D. Scepticism / 1. Scepticism
The basis of scepticism is the claim that every proposition has an equal opposing proposition [Sext.Empiricus]
13. Knowledge Criteria / D. Scepticism / 3. Illusion Scepticism
The necks of doves appear different in colour depending on the angle of viewing [Sext.Empiricus]
The same oar seems bent in water and straight when out of it [Sext.Empiricus]
The same tower appears round from a distance, but square close at hand [Sext.Empiricus]
If we press the side of an eyeball, objects appear a different shape [Sext.Empiricus]
13. Knowledge Criteria / D. Scepticism / 6. Scepticism Critique
How can sceptics show there is no criterion? Weak without, contradiction with [Sext.Empiricus]
13. Knowledge Criteria / E. Relativism / 1. Relativism
How can we judge between our impressions and those of other animals, when we ourselves are involved? [Sext.Empiricus]
13. Knowledge Criteria / E. Relativism / 3. Subjectivism
Water that seems lukewarm can seem very hot on inflamed skin [Sext.Empiricus]
Some actions seem shameful when sober but not when drunk [Sext.Empiricus]
If we had no hearing or sight, we would assume no sound or sight exists, so there may be unsensed qualities [Sext.Empiricus]
Sickness is perfectly natural to the sick, so their natural perceptions should carry some weight [Sext.Empiricus]
If we enjoy different things, presumably we receive different impressions [Sext.Empiricus]
13. Knowledge Criteria / E. Relativism / 4. Cultural relativism
With us it is shameful for men to wear earrings, but among Syrians it is considered noble [Sext.Empiricus]
Even if all known nations agree on a practice, there may be unknown nations which disagree [Sext.Empiricus]
14. Science / A. Basis of Science / 1. Observation
How can you investigate without some preconception of your object? [Sext.Empiricus]
14. Science / A. Basis of Science / 6. Falsification
We only discard a hypothesis after one failure if it appears likely to keep on failing [Ayer]
14. Science / C. Induction / 2. Aims of Induction
The induction problem is to prove generalisations about the future based on the past [Ayer]
Induction passes from particular facts to other particulars, or to general laws, non-deductively [Ayer]
14. Science / C. Induction / 3. Limits of Induction
We can't use the uniformity of nature to prove induction, as that would be circular [Ayer]
If you don't view every particular, you may miss the one which disproves your universal induction [Sext.Empiricus]
15. Nature of Minds / A. Nature of Mind / 1. Mind / c. Features of mind
Intelligence is aware of itself, so the intelligence is both the thinker and the thought [Porphyry]
15. Nature of Minds / A. Nature of Mind / 1. Mind / d. Location of mind
The soul is everywhere and nowhere in the body, and must be its cause [Porphyry]
15. Nature of Minds / A. Nature of Mind / 4. Other Minds / b. Scepticism of other minds
Other minds are 'metaphysical' objects, because I can never observe their experiences [Ayer]
Maybe induction could never prove the existence of something unobservable [Ayer]
15. Nature of Minds / A. Nature of Mind / 4. Other Minds / c. Knowing other minds
A conscious object is by definition one that behaves in a certain way, so behaviour proves consciousness [Ayer]
The argument from analogy fails, so the best account of other minds is behaviouristic [Ayer]
The theory of other minds has no rival [Ayer]
Originally I combined a mentalistic view of introspection with a behaviouristic view of other minds [Ayer]
Physicalism undercuts the other mind problem, by equating experience with 'public' brain events [Ayer]
15. Nature of Minds / C. Capacities of Minds / 6. Idealisation
If we try to conceive of a line with no breadth, it ceases to exist, and so has no length [Sext.Empiricus]
16. Persons / B. Nature of the Self / 1. Self and Consciousness
Consciousness must involve a subject, and only bodies identify subjects [Ayer]
16. Persons / B. Nature of the Self / 5. Self as Associations
If the self is meaningful, it must be constructed from sense-experiences [Ayer]
Qualia must be united by a subject, because they lead to concepts and judgements [Ayer]
Is something an 'experience' because it relates to other experiences, or because it relates to a subject? [Ayer]
16. Persons / B. Nature of the Self / 7. Self and Body / a. Self needs body
Bodily identity and memory work together to establish personal identity [Ayer]
Two experiences belong to one self if their contents belong with one body [Ayer]
Empiricists can define personal identity as bodily identity, which consists of sense-contents [Ayer]
People own conscious states because they are causally related to the identifying body [Ayer]
16. Persons / C. Self-Awareness / 2. Knowing the Self
Successful introspection reveals the substrate along with the object of thought [Porphyry]
Self-consciousness is not basic, because experiences are not instrinsically marked with ownership [Ayer]
16. Persons / C. Self-Awareness / 3. Limits of Introspection
We identify experiences by their owners, so we can't define owners by their experiences [Ayer]
16. Persons / D. Continuity of the Self / 2. Mental Continuity / a. Memory is Self
Memory is the best proposal as what unites bundles of experiences [Ayer]
Not all exerience can be remembered, as this would produce an infinite regress [Ayer]
16. Persons / D. Continuity of the Self / 2. Mental Continuity / c. Inadequacy of mental continuity
Temporal gaps in the consciousness of a spirit could not be bridged by memories [Ayer]
16. Persons / D. Continuity of the Self / 6. Body sustains Self
Personal identity can't just be relations of experiences, because the body is needed to identify them [Ayer]
17. Mind and Body / A. Mind-Body Dualism / 1. Dualism
The soul is bound to matter by the force of its own disposition [Porphyry]
17. Mind and Body / A. Mind-Body Dualism / 8. Dualism of Mind Critique
The supposed 'gulf' between mind and matter is based on the senseless concept of 'substances' [Ayer]
17. Mind and Body / D. Property Dualism / 4. Emergentism
The incorporeal is not in the nature of body, and so could not emerge from it [Sext.Empiricus]
17. Mind and Body / E. Mind as Physical / 1. Physical Mind
Why shouldn't we say brain depends on mind? Better explanation! [Ayer]
18. Thought / A. Modes of Thought / 6. Judgement / a. Nature of Judgement
If we utter three steps of a logical argument, they never exist together [Sext.Empiricus]
18. Thought / D. Concepts / 2. Origin of Concepts / b. Empirical concepts
We can only dream of a winged man if we have experienced men and some winged thing [Sext.Empiricus]
19. Language / A. Nature of Meaning / 5. Meaning as Verification
A sentence is factually significant to someone if they know how to verify its proposition [Ayer]
Factual propositions imply (in conjunction with a few other premises) possible experiences [Ayer]
Tautologies and empirical hypotheses form the entire class of significant propositions [Ayer]
A statement is meaningful if observation statements can be deduced from it [Ayer]
Directly verifiable statements must entail at least one new observation statement [Ayer]
The principle of verification is not an empirical hypothesis, but a definition [Ayer]
19. Language / D. Propositions / 1. Propositions
Sentences only express propositions if they are meaningful; otherwise they are 'statements' [Ayer]
19. Language / D. Propositions / 6. Propositions Critique
Talk of propositions is just shorthand for talking about equivalent sentences [Ayer]
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / b. Defining ethics
Some people think there are ethical facts, but of a 'queer' sort [Ayer]
A right attitude is just an attitude one is prepared to stand by [Ayer]
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / d. Ethical theory
Moral theories are all meta-ethical, and are neutral as regards actual conduct [Ayer]
Moral judgements cannot be the logical consequence of a moral philosophy [Ayer]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / c. Ethical intuitionism
Moral intuition is worthless if there is no criterion to decide between intuitions [Ayer]
I would describe intuitions of good as feelings of approval [Ayer]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / e. Human nature
Justice is each person fulfilling his function [Porphyry]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / h. Expressivism
Approval of historical or fictional murders gives us leave to imitate them [Ayer]
Moral judgements are not expressions, but are elements in a behaviour pattern [Ayer]
Ayer defends the emotivist version of expressivism [Ayer, by Smith,M]
To say an act is wrong makes no further statement about it, but merely expresses disapproval [Ayer]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / i. Prescriptivism
Moral approval and disapproval concerns classes of actions, rather than particular actions [Ayer]
22. Metaethics / B. Value / 2. Values / g. Love
We should avoid the pleasures of love, or at least, should not enact our dreams [Porphyry]
22. Metaethics / C. The Good / 1. Goodness / a. Form of the Good
Saying the good is useful or choiceworth or happiness-creating is not the good, but a feature of it [Sext.Empiricus]
22. Metaethics / C. The Good / 1. Goodness / b. Types of good
Like a warming fire, what is good by nature should be good for everyone [Sext.Empiricus]
22. Metaethics / C. The Good / 2. Happiness / d. Routes to happiness
If a desire is itself desirable, then we shouldn't desire it, as achieving it destroys it [Sext.Empiricus]
23. Ethics / B. Contract Ethics / 9. Contractualism
Right actions, once done, are those with a reasonable justification [Sext.Empiricus]
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / c. Motivation for virtue
Civil virtues make us behave benevolently, and thereby unite citizens [Porphyry]
Civil virtues control the passions, and make us conform to our nature [Porphyry]
Purificatory virtues detach the soul completely from the passions [Porphyry]
23. Ethics / C. Virtue Theory / 3. Virtues / a. Virtues
There are practical, purificatory, contemplative, and exemplary virtues [Porphyry]
26. Natural Theory / A. Speculations on Nature / 1. Nature
Unified real existence is neither great nor small, though greatness and smallness participate in it [Porphyry]
26. Natural Theory / A. Speculations on Nature / 4. Mathematical Nature
The tektraktys (1+2+3+4=10) is the 'fount of ever-flowing nature' [Sext.Empiricus]
26. Natural Theory / C. Causation / 4. Naturalised causation
Some say that causes are physical, some say not [Sext.Empiricus]
26. Natural Theory / C. Causation / 7. Eliminating causation
Knowing an effect results from a cause means knowing that the cause belongs with the effect, which is circular [Sext.Empiricus]
Cause can't exist before effect, or exist at the same time, so it doesn't exist [Sext.Empiricus]
If there were no causes then everything would have been randomly produced by everything [Sext.Empiricus]
26. Natural Theory / C. Causation / 8. Particular Causation / c. Conditions of causation
Causes are either equal to the effect, or they link equally with other causes, or they contribute slightly [Sext.Empiricus]
26. Natural Theory / C. Causation / 9. General Causation / d. Causal necessity
The attribution of necessity to causation is either primitive animism, or confusion with logical necessity [Ayer]
27. Natural Reality / A. Classical Physics / 1. Mechanics / a. Explaining movement
If time and place are infinitely divided, it becomes impossible for movement ever to begin [Sext.Empiricus]
If all atoms, times and places are the same, everything should move with equal velocity [Sext.Empiricus]
A man walking backwards on a forwards-moving ship is moving in a fixed place [Sext.Empiricus]
Does the original self-mover push itself from behind, or pull itself from in front? [Sext.Empiricus]
27. Natural Reality / D. Time / 1. Nature of Time / b. Relative time
If motion and rest are abolished, so is time [Sext.Empiricus]
27. Natural Reality / D. Time / 1. Nature of Time / c. Idealist time
Time is the circular movement of the soul [Porphyry]
27. Natural Reality / D. Time / 1. Nature of Time / e. Eventless time
Some think time is seen at rest, as well as in movement [Porphyry]
27. Natural Reality / D. Time / 1. Nature of Time / i. Denying time
Time must be unlimited, but past and present can't be non-existent, and can't be now, so time does not exist [Sext.Empiricus]
27. Natural Reality / D. Time / 2. Passage of Time / c. Tenses and time
Time doesn't end with the Universe, because tensed statements about destruction remain true [Sext.Empiricus]
27. Natural Reality / D. Time / 3. Parts of Time / c. Intervals
Time is divisible, into past, present and future [Sext.Empiricus]
How can time be divisible if we can't compare one length of time with another? [Sext.Empiricus]
27. Natural Reality / D. Time / 3. Parts of Time / e. Present moment
Socrates either dies when he exists (before his death) or when he doesn't (after his death) [Sext.Empiricus]
If the present is just the limit of the past or the future, it can't exist because they don't exist [Sext.Empiricus]
28. God / A. Divine Nature / 2. Divine Nature
All men agree that God is blessed, imperishable, happy and good [Sext.Empiricus]
God is nowhere, and hence everywhere [Porphyry]
How can we agree on the concept of God, unless we agree on his substance or form or place? [Sext.Empiricus]
God must suffer to understand suffering [Sext.Empiricus]
28. God / A. Divine Nature / 3. Divine Perfections
The Divine must lack the virtues of continence and fortitude, because they are not needed [Sext.Empiricus]
28. God / A. Divine Nature / 4. Divine Contradictions
A person with non-empirical attributes is unintelligible. [Ayer]
28. God / B. Proving God / 1. Proof of God
God is defended by agreement, order, absurdity of denying God, and refutations [Sext.Empiricus]
28. God / B. Proving God / 2. Proofs of Reason / b. Ontological Proof critique
God's sensations imply change, and hence perishing, which is absurd, so there is no such God [Sext.Empiricus]
God without virtue is absurd, but God's virtues will be better than God [Sext.Empiricus]
The existence of God can't be self-evident or everyone would have agreed on it, so it needs demonstration [Sext.Empiricus]
When we ascribe an attribute to a thing, we covertly assert that it exists [Ayer]
28. God / B. Proving God / 3. Proofs of Evidence / b. Teleological Proof
The original substance lacked motion or shape, and was given these by a cause [Sext.Empiricus]
28. God / C. Attitudes to God / 2. Pantheism
Everything existing proceeds from divinity, and is within divinity [Porphyry]
28. God / C. Attitudes to God / 4. God Reflects Humanity
The perfections of God were extrapolations from mankind [Sext.Empiricus]
28. God / C. Attitudes to God / 5. Atheism
If theism is non-sensical, then so is atheism. [Ayer]
Gods were invented as watchers of people's secret actions [Sext.Empiricus]
An incorporeal God could do nothing, and a bodily god would perish, so there is no God [Sext.Empiricus]
29. Religion / A. Polytheistic Religion / 1. Animism
It is mad to think that what is useful to us, like lakes and rivers, are gods [Sext.Empiricus]
29. Religion / D. Religious Issues / 1. Religious Commitment / c. Religious Verification
The 'truths' expressed by theists are not literally significant [Ayer]
29. Religion / D. Religious Issues / 2. Immortality / b. Soul
Nature binds or detaches body to soul, but soul itself joins and detaches soul from body [Porphyry]
Individual souls are all connected, though distinct, and without dividing universal Soul [Porphyry]
29. Religion / D. Religious Issues / 3. Problem of Evil / d. Natural Evil
If God foresaw evil he would presumably prevent it, and if he only foresees some things, why those things? [Sext.Empiricus]