Ideas from 'Language,Truth and Logic' by A.J. Ayer [1936], by Theme Structure
[found in 'Language, Truth and Logic' by Ayer,A.J. [Penguin 1974,0-14-021200-0]].
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1. Philosophy / D. Nature of Philosophy / 3. Philosophy Defined
5196
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Philosophy is a department of logic
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1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / e. Philosophy as reason
5189
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Philosophers should abandon speculation, as philosophy is wholly critical
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1. Philosophy / E. Nature of Metaphysics / 7. Against Metaphysics
7919
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Humeans rejected the a priori synthetic, and so rejected even Kantian metaphysics [Macdonald,C]
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1. Philosophy / F. Analytic Philosophy / 7. Limitations of Analysis
5195
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Critics say analysis can only show the parts, and not their distinctive configuration
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1. Philosophy / G. Scientific Philosophy / 3. Scientism
5179
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Philosophy deals with the questions that scientists do not wish to handle
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3. Truth / H. Deflationary Truth / 2. Deflationary Truth
4749
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We cannot analyse the concept of 'truth', because it is simply a mark that a sentence is asserted
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6. Mathematics / C. Sources of Mathematics / 6. Logicism / a. Early logicism
5202
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Maths and logic are true universally because they are analytic or tautological
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7. Existence / D. Theories of Reality / 1. Ontologies
6523
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Positivists regard ontology as either meaningless or stipulated [Robinson,H]
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11. Knowledge Aims / B. Certain Knowledge / 1. Certainty
5183
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Only tautologies can be certain; other propositions can only be probable
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11. Knowledge Aims / C. Knowing Reality / 2. Phenomenalism
6525
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Logical positivists could never give the sense-data equivalent of 'there is a table next door' [Robinson,H]
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5170
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Material things are constructions from actual and possible occurrences of sense-contents
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12. Knowledge Sources / A. A Priori Knowledge / 4. A Priori as Necessities
5198
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We could verify 'a thing can't be in two places at once' by destroying one of the things [Ierubino]
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12. Knowledge Sources / A. A Priori Knowledge / 5. A Priori Synthetic
2619
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Whether geometry can be applied to reality is an empirical question outside of geometry
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12. Knowledge Sources / A. A Priori Knowledge / 7. A Priori from Convention
5197
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By changing definitions we could make 'a thing can't be in two places at once' a contradiction
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12. Knowledge Sources / A. A Priori Knowledge / 8. A Priori as Analytic
5204
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To say that a proposition is true a priori is to say that it is a tautology
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12. Knowledge Sources / B. Perception / 4. Sense Data / a. Sense-data theory
6524
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Positivists prefer sense-data to objects, because the vocabulary covers both illusions and perceptions [Robinson,H]
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12. Knowledge Sources / B. Perception / 7. Causal Perception
5193
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Causal and representative theories of perception are wrong as they refer to unobservables
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12. Knowledge Sources / C. Rationalism / 1. Rationalism
5200
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The main claim of rationalism is that thought is an independent source of knowledge
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12. Knowledge Sources / D. Empiricism / 1. Empiricism
4729
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Empiricism lacked a decent account of the a priori, until Ayer said it was entirely analytic [O'Grady]
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5180
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All propositions (especially 'metaphysics') must begin with the senses
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5169
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My empiricism logically distinguishes analytic and synthetic propositions, and metaphysical verbiage
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12. Knowledge Sources / D. Empiricism / 4. Pro-Empiricism
5185
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It is further sense-experience which informs us of the mistakes that arise out of sense-experience
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12. Knowledge Sources / D. Empiricism / 5. Empiricism Critique
5199
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Empiricism, it is said, cannot account for our knowledge of necessary truths
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14. Science / C. Induction / 2. Aims of Induction
5190
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The induction problem is to prove generalisations about the future based on the past
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14. Science / C. Induction / 3. Limits of Induction
5191
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We can't use the uniformity of nature to prove induction, as that would be circular
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15. Nature of Minds / A. Nature of Mind / 4. Other Minds / b. Scepticism of other minds
5177
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Other minds are 'metaphysical' objects, because I can never observe their experiences
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15. Nature of Minds / A. Nature of Mind / 4. Other Minds / c. Knowing other minds
5178
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A conscious object is by definition one that behaves in a certain way, so behaviour proves consciousness
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16. Persons / B. Nature of the Self / 5. Self as Associations
5172
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If the self is meaningful, it must be constructed from sense-experiences
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16. Persons / B. Nature of the Self / 7. Self and Body / a. Self needs body
5173
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Two experiences belong to one self if their contents belong with one body
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5176
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Empiricists can define personal identity as bodily identity, which consists of sense-contents
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17. Mind and Body / A. Mind-Body Dualism / 8. Dualism of Mind Critique
5171
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The supposed 'gulf' between mind and matter is based on the senseless concept of 'substances'
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19. Language / A. Nature of Meaning / 5. Meaning as Verification
5181
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A sentence is factually significant to someone if they know how to verify its proposition
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5184
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Factual propositions imply (in conjunction with a few other premises) possible experiences
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5186
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Tautologies and empirical hypotheses form the entire class of significant propositions
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22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / c. Ethical intuitionism
5205
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Moral intuition is worthless if there is no criterion to decide between intuitions
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22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / h. Expressivism
23725
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Ayer defends the emotivist version of expressivism [Smith,M]
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5206
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To say an act is wrong makes no further statement about it, but merely expresses disapproval
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28. God / A. Divine Nature / 4. Divine Contradictions
5208
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A person with non-empirical attributes is unintelligible.
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28. God / B. Proving God / 2. Proofs of Reason / b. Ontological Proof critique
5187
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When we ascribe an attribute to a thing, we covertly assert that it exists
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28. God / C. Attitudes to God / 5. Atheism
5207
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If theism is non-sensical, then so is atheism.
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29. Religion / D. Religious Issues / 1. Religious Commitment / c. Religious Verification
5209
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The 'truths' expressed by theists are not literally significant
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