A.J. Ayer, Language, Truth and Logic (1936)



Preface to the First Edition


Accepts Hume's position (31)


o     Relations of ideas

A priori propositions of logic and pure mathematics

Necessary, because analytic

o     Cannot be confuted by experience because make no assertion about empirical world

o     Simply record our determination to use symbols in a certain fashion


o     Matters of fact

Hypothetical propositions about empirical state of affairs

Probable and require verification

o     Must have possible sense-experience relevant to determination of truth or falsity

o     Make sense but can never be apodictic

   Radicalizes Hume's position


o     Locus of metaphysical propositions

Ayer does not see as possible on level of relations of ideas

Presents as on level of hypothesizes, which makes them empirical (i.e., factual) claims requiring verification


o     Status of metaphysical propositions

Criteria of sense:  either empirically verifiable or analytically tautologica

If propositions neither empirically verifiable nor analytically tautological, they are metaphysical

o     Neither true nor false

o     Literally senseless (early Wittgenstein would say non-sense)



   The Function of Philosophy (32)


o     Elimination of prior role

Not present speculative truth that competes with hypotheses of science

Not pass a priori judgment on validity of scientific theories


o     Limitation on current role

Clarify the propositions of science

o     Exhibit logical relationships

o     Define symbols that occur in them

No basis for conflicting philosophical schools

o     No dissent allowed

o     Orthodoxy imposed




The Elimination of Metaphysics (33)


Critique of Metaphysical Knowledge


o     Metaphysics claims knowledge of reality transcending world of science & common sense


o     Ayer assumes premises of metaphysical propositions were deduced

Many metaphysicians claim intuition of first principle

If deduced, Ayer assumes based on evidence from senses

o     Ayer does not consider evidence from understanding

o     Ayer does not allow reason to have synthetic function, only analytic

Cannot infer super-empirical properties from empirical premises


o     Response to claim of intellectual intuition

Even if shown they use empirical premises, metaphysicians claim their super-empirical inferences not necessarily false simply because conclusions not follow from premises

Ayer shifts to criticism of nature of metaphysical statements per se

o     Ayer's non-verifiable claim:  "no statement which refers to a 'reality' transcending the limits of all possible sense-experience can possibly have any literal significance" (34)

o     Ayer equates literal significance with empirical reference



  Reflections on Kant


o     Kant rejected transcendent metaphysics

Rejected as factual impossibility

Ayer rejects as logical impossibility as well, contra Kant


o     Critique of Kant
Kant assumes we can assert reality of things beyond sense-experience

Ayer claims this assertion requires Kant to have succeeded in going beyond the boundary

o   If locked into experience, locked into total phenomenalism

o Not only is thought of such a super-empirical reality non-factual but also it is illogical

q  Ayer does not address whether illogical like a round square

q      Ayer does not address whether illogical like a mermaid

q Ayer does not address whether illogical only from phenomenalistic assumptions

¤ Does not consider transcendental deduction that noumenal lies behind phenomenal

¤  If transcendental deduction possible, only constraint for human cognition is non-contradiction in asserting one of the antinomies of noumenal possibility as thinkable and practical


  Basis for rejecting metaphysics


o     Not from psychological hypothesis on constitution of human mind (35)


o     "From the rule which determines the literal significance of language"

Metaphysics "produces sentences which fail to conform to the conditions under which alone a sentence can be literally significant"

Verification principle:  a proposition is factually significant if and only if one knows how to verify it

o     Transcendent metaphysics does claim factual

o     Transcendental metaphysics does not claim factual

q      Genuine rejection cannot be based on verification

q   If reject must do so by undercutting synthetic a priori judgments of reason

¤ Critique tends to focus on propositions

¤Judgment not restricted to same criteria as propositions


o     Defense of weak verification principle (36)

Ayer rejects conclusive verification

Ayer rejects conclusive confutation


o     Philosophy must distinguish itself from metaphysics (41)


o     Emergence of metaphysics from grammatical confusion

In language, we predicate sensible properties to a thing

Metaphysics assumes the thing itself is distinct from predications

o     Only language distinguished the thing from its appearance

o     Thing is not distinct from its appearance

¤   Ayer himself makes an inference about things on the basis of language

¤   Ayer himself makes a metaphysical claim with assertion of phenomenalism


  Status of metaphysics


o     Some see metaphysician as misplaced poet (44)


o     Ayer rejects

Sentences of poets generally do have literal meaning

Sentences of metaphysics have no literal meaning





Truth and Probability




o     True and false

Terms connote nothing (88)

Function in sentence as marks of assertion and denial (89)


o     Conversion to verification

"What is truth?"= "what is the analysis of the sentence 'p is true'?"

Therefore, for Ayer, no problem of truth


o     Shift from ontology to linguistics



 Empirical proposition


o     Different way to determine validity than that for analytic proposition


o     Validity of synthetic proposition not purely formal



 Possibility of certain and hypothetical synthetic propositions


o     Certain would be ostensive and the rest would be hypothetical


o     Ayer rejects possibility of totally ostensive proposition (91)


¤      For language to point, it must describe

¤      As classifying, language goes beyond given



    All empirical propositions, then, hypothetical

o     Verify by sense-experience


o Therefore, since propositions recording these observations are also hypotheses requiring verification, no final proposition (no absolute certainty for empirical propositions)


o Facts can never compel us to abandon a hypothesis (critique of fundamentalism) (95)


o     Hypothesis and definition

Can shift

Can begin with "All A's are B's" as synthetic generalization (hypothetical) and later take as a tautology (definition)



    Hypothesis formation


o     In order to anticipate the course of our sensations (97)


o    "We alter our system because we think that by altering it we shall make it a more efficient instrument for the anticipation of experience" (98)



    Criteria for validity of empirical proposition


o     Validate

¤      Observation confirms

¤      Not establish absolutely, only increase probability


o     Invalidate

¤      Observation not confirm

¤      Not refute absolutely, only decrease probability


   Adds criteria of rationality


o Definition of rationality:  "to be rational is simply to employ a self-consistent accredited procedure in the formation of all one's beliefs" (100)


o     Links to current social norm



o     Does not address rationality of social norm

¤      Fascism as rational and capitalism as rational

¤  Cannot make the context of rationality problematic and no basis of establishing one mode of rationality over others (they are mere hypotheses)


o  "The probability of a proposition is determined both by the nature of our observations and by our concept of rationality" (101)