Combining Philosophers

All the ideas for Menedemus, Alfred Tarski and Thomas Aquinas

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189 ideas

1. Philosophy / A. Wisdom / 2. Wise People
Wise people should contemplate and discuss the truth, and fight against falsehood [Aquinas]
1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / a. Philosophy as worldly
Philosophy aims to know the truth about the way things are [Aquinas]
1. Philosophy / E. Nature of Metaphysics / 5. Metaphysics beyond Science
Some say metaphysics is a highly generalised empirical study of objects [Tarski]
1. Philosophy / F. Analytic Philosophy / 1. Nature of Analysis
Disputes that fail to use precise scientific terminology are all meaningless [Tarski]
2. Reason / A. Nature of Reason / 1. On Reason
We are coerced into assent to a truth by reason's violence [Aquinas]
2. Reason / A. Nature of Reason / 4. Aims of Reason
The mind is compelled by necessary truths, but not by contingent truths [Aquinas]
2. Reason / B. Laws of Thought / 6. Ockham's Razor
Supposing many principles is superfluous if a few will do it [Aquinas]
2. Reason / C. Styles of Reason / 1. Dialectic
Arguing with opponents uncovers truths, and restrains falsehoods [Aquinas]
2. Reason / D. Definition / 1. Definitions
For a definition we need the words or concepts used, the rules, and the structure of the language [Tarski]
2. Reason / D. Definition / 5. Genus and Differentia
If definitions must be general, and general terms can't individuate, then Socrates can't be defined [Aquinas, by Cover/O'Leary-Hawthorne]
The definitions expressing identity are used to sort things [Aquinas]
3. Truth / A. Truth Problems / 1. Truth
Truth is universal, but knowledge of it is not [Aquinas]
Types of lying: Speak lies, intend lies, intend deception, aim at deceptive goal? [Aquinas, by Tuckness/Wolf]
3. Truth / A. Truth Problems / 2. Defining Truth
Tarski proved that truth cannot be defined from within a given theory [Tarski, by Halbach]
Tarski proved that any reasonably expressive language suffers from the liar paradox [Tarski, by Horsten]
'True sentence' has no use consistent with logic and ordinary language, so definition seems hopeless [Tarski]
In everyday language, truth seems indefinable, inconsistent, and illogical [Tarski]
Definitions of truth should not introduce a new version of the concept, but capture the old one [Tarski]
A definition of truth should be materially adequate and formally correct [Tarski]
A rigorous definition of truth is only possible in an exactly specified language [Tarski]
We may eventually need to split the word 'true' into several less ambiguous terms [Tarski]
3. Truth / A. Truth Problems / 3. Value of Truth
For the mind Good is one truth among many, and Truth is one good among many [Aquinas]
3. Truth / A. Truth Problems / 9. Rejecting Truth
If the existence of truth is denied, the 'Truth does not exist' must be true! [Aquinas]
3. Truth / C. Correspondence Truth / 1. Correspondence Truth
Truth is the conformity of being to intellect [Aquinas]
3. Truth / C. Correspondence Truth / 3. Correspondence Truth critique
Tarski's Theorem renders any precise version of correspondence impossible [Tarski, by Halbach]
3. Truth / F. Semantic Truth / 1. Tarski's Truth / a. Tarski's truth definition
Tarskian semantics says that a sentence is true iff it is satisfied by every sequence [Tarski, by Hossack]
'"It is snowing" is true if and only if it is snowing' is a partial definition of the concept of truth [Tarski]
Tarski gave up on the essence of truth, and asked how truth is used, or how it functions [Tarski, by Horsten]
Tarski did not just aim at a definition; he also offered an adequacy criterion for any truth definition [Tarski, by Halbach]
Tarski enumerates cases of truth, so it can't be applied to new words or languages [Davidson on Tarski]
Tarski define truths by giving the extension of the predicate, rather than the meaning [Davidson on Tarski]
Tarski made truth relative, by only defining truth within some given artificial language [Tarski, by O'Grady]
Tarski has to avoid stating how truths relate to states of affairs [Kirkham on Tarski]
It is convenient to attach 'true' to sentences, and hence the language must be specified [Tarski]
In the classical concept of truth, 'snow is white' is true if snow is white [Tarski]
Scheme (T) is not a definition of truth [Tarski]
Each interpreted T-sentence is a partial definition of truth; the whole definition is their conjunction [Tarski]
Use 'true' so that all T-sentences can be asserted, and the definition will then be 'adequate' [Tarski]
We don't give conditions for asserting 'snow is white'; just that assertion implies 'snow is white' is true [Tarski]
3. Truth / F. Semantic Truth / 1. Tarski's Truth / b. Satisfaction and truth
Truth only applies to closed formulas, but we need satisfaction of open formulas to define it [Burgess on Tarski]
Tarski uses sentential functions; truly assigning the objects to variables is what satisfies them [Tarski, by Rumfitt]
We can define the truth predicate using 'true of' (satisfaction) for variables and some objects [Tarski, by Horsten]
For physicalism, reduce truth to satisfaction, then define satisfaction as physical-plus-logic [Tarski, by Kirkham]
Insight: don't use truth, use a property which can be compositional in complex quantified sentence [Tarski, by Kirkham]
Tarski gave axioms for satisfaction, then derived its explicit definition, which led to defining truth [Tarski, by Davidson]
The best truth definition involves other semantic notions, like satisfaction (relating terms and objects) [Tarski]
Specify satisfaction for simple sentences, then compounds; true sentences are satisfied by all objects [Tarski]
3. Truth / F. Semantic Truth / 1. Tarski's Truth / c. Meta-language for truth
We can't use a semantically closed language, or ditch our logic, so a meta-language is needed [Tarski]
The metalanguage must contain the object language, logic, and defined semantics [Tarski]
3. Truth / F. Semantic Truth / 2. Semantic Truth
Tarski defined truth for particular languages, but didn't define it across languages [Davidson on Tarski]
Tarski didn't capture the notion of an adequate truth definition, as Convention T won't prove non-contradiction [Halbach on Tarski]
Tarski says that his semantic theory of truth is completely neutral about all metaphysics [Tarski, by Haack]
Physicalists should explain reference nonsemantically, rather than getting rid of it [Tarski, by Field,H]
A physicalist account must add primitive reference to Tarski's theory [Field,H on Tarski]
If listing equivalences is a reduction of truth, witchcraft is just a list of witch-victim pairs [Field,H on Tarski]
Tarski made truth respectable, by proving that it could be defined [Tarski, by Halbach]
Tarski had a theory of truth, and a theory of theories of truth [Tarski, by Read]
Tarski's 'truth' is a precise relation between the language and its semantics [Tarski, by Walicki]
Tarskian truth neglects the atomic sentences [Mulligan/Simons/Smith on Tarski]
3. Truth / G. Axiomatic Truth / 1. Axiomatic Truth
Tarski's had the first axiomatic theory of truth that was minimally adequate [Tarski, by Horsten]
Tarski defined truth, but an axiomatisation can be extracted from his inductive clauses [Tarski, by Halbach]
Tarski thought axiomatic truth was too contingent, and in danger of inconsistencies [Tarski, by Davidson]
We need an undefined term 'true' in the meta-language, specified by axioms [Tarski]
3. Truth / H. Deflationary Truth / 1. Redundant Truth
Truth can't be eliminated from universal claims, or from particular unspecified claims [Tarski]
3. Truth / H. Deflationary Truth / 2. Deflationary Truth
Semantics is a very modest discipline which solves no real problems [Tarski]
4. Formal Logic / B. Propositional Logic PL / 3. Truth Tables
Truth tables give prior conditions for logic, but are outside the system, and not definitions [Tarski]
5. Theory of Logic / A. Overview of Logic / 3. Value of Logic
Set theory and logic are fairy tales, but still worth studying [Tarski]
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
There is no clear boundary between the logical and the non-logical [Tarski]
5. Theory of Logic / A. Overview of Logic / 6. Classical Logic
A language: primitive terms, then definition rules, then sentences, then axioms, and finally inference rules [Tarski]
5. Theory of Logic / B. Logical Consequence / 1. Logical Consequence
If a syllogism admits one absurdity, others must follow [Aquinas]
Split out the logical vocabulary, make an assignment to the rest. It's logical if premises and conclusion match [Tarski, by Rumfitt]
5. Theory of Logic / B. Logical Consequence / 4. Semantic Consequence |=
Logical consequence is when in any model in which the premises are true, the conclusion is true [Tarski, by Beall/Restall]
Logical consequence: true premises give true conclusions under all interpretations [Tarski, by Hodges,W]
X follows from sentences K iff every model of K also models X [Tarski]
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
The truth definition proves semantic contradiction and excluded middle laws (not the logic laws) [Tarski]
5. Theory of Logic / D. Assumptions for Logic / 4. Identity in Logic
Identity is invariant under arbitrary permutations, so it seems to be a logical term [Tarski, by McGee]
5. Theory of Logic / F. Referring in Logic / 1. Naming / c. Names as referential
A name denotes an object if the object satisfies a particular sentential function [Tarski]
5. Theory of Logic / I. Semantics of Logic / 1. Semantics of Logic
Tarski built a compositional semantics for predicate logic, from dependent satisfactions [Tarski, by McGee]
Tarksi invented the first semantics for predicate logic, using this conception of truth [Tarski, by Kirkham]
Semantics is the concepts of connections of language to reality, such as denotation, definition and truth [Tarski]
A language containing its own semantics is inconsistent - but we can use a second language [Tarski]
5. Theory of Logic / I. Semantics of Logic / 4. Satisfaction
A sentence is satisfied when we can assert the sentence when the variables are assigned [Tarski]
Satisfaction is the easiest semantical concept to define, and the others will reduce to it [Tarski]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
The object language/ metalanguage distinction is the basis of model theory [Tarski, by Halbach]
A 'model' is a sequence of objects which satisfies a complete set of sentential functions [Tarski]
5. Theory of Logic / K. Features of Logics / 2. Consistency
Using the definition of truth, we can prove theories consistent within sound logics [Tarski]
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / a. The Liar paradox
Tarski avoids the Liar Paradox, because truth cannot be asserted within the object language [Tarski, by Fisher]
The Liar makes us assert a false sentence, so it must be taken seriously [Tarski]
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
Tarski improved Hilbert's geometry axioms, and without set-theory [Tarski, by Feferman/Feferman]
6. Mathematics / C. Sources of Mathematics / 7. Formalism
Tarski's theory of truth shifted the approach away from syntax, to set theory and semantics [Feferman/Feferman on Tarski]
7. Existence / A. Nature of Existence / 3. Being / e. Being and nothing
If affirmative propositions express being, we affirm about what is absent [Aquinas]
7. Existence / A. Nature of Existence / 3. Being / f. Primary being
Being is basic to thought, and all other concepts are additions to being [Aquinas]
7. Existence / A. Nature of Existence / 3. Being / g. Particular being
Being implies distinctness, which implies division, unity, and multitude [Aquinas]
7. Existence / D. Theories of Reality / 5. Naturalism
Non-human things are explicable naturally, and voluntary things by the will, so God is not needed [Aquinas]
7. Existence / E. Categories / 4. Category Realism
Different genera are delimited by modes of predication, which rest on modes of being [Aquinas]
8. Modes of Existence / B. Properties / 8. Properties as Modes
Whiteness does not exist, but by it something can exist-as-white [Aquinas]
Properties have an incomplete essence, with definitions referring to their subject [Aquinas]
8. Modes of Existence / D. Universals / 6. Platonic Forms / d. Forms critiques
If the form of 'human' contains 'many', Socrates isn't human; if it contains 'one', Socrates is Plato [Aquinas]
8. Modes of Existence / E. Nominalism / 1. Nominalism / a. Nominalism
I am a deeply convinced nominalist [Tarski]
9. Objects / A. Existence of Objects / 5. Individuation / a. Individuation
The principle of diversity for corporeal substances is their matter [Aquinas, by Cover/O'Leary-Hawthorne]
9. Objects / B. Unity of Objects / 1. Unifying an Object / b. Unifying aggregates
'One' can mean undivided and not a multitude, or it can add measurement, giving number [Aquinas]
9. Objects / C. Structure of Objects / 2. Hylomorphism / d. Form as unifier
Humans only have a single substantial form, which contains the others and acts for them [Aquinas]
One thing needs a single thing to unite it; if there were two forms, something must unite them [Aquinas]
9. Objects / D. Essence of Objects / 1. Essences of Objects
It is by having essence that things exist [Aquinas]
9. Objects / D. Essence of Objects / 2. Types of Essence
Specific individual essence is defined by material, and generic essence is defined by form [Aquinas]
9. Objects / D. Essence of Objects / 4. Essence as Definition
The definition of a physical object must include the material as well as the form [Aquinas]
9. Objects / D. Essence of Objects / 5. Essence as Kind
Essence is something in common between the natures which sort things into categories [Aquinas]
9. Objects / D. Essence of Objects / 6. Essence as Unifier
A simple substance is its own essence [Aquinas]
11. Knowledge Aims / A. Knowledge / 2. Understanding
Senses grasp external properties, but the understanding grasps the essential natures of things [Aquinas]
11. Knowledge Aims / B. Certain Knowledge / 1. Certainty
The conclusions of speculative reason about necessities are certain [Aquinas]
11. Knowledge Aims / C. Knowing Reality / 1. Perceptual Realism / b. Direct realism
A knowing being possesses a further reality, the 'presence' of the thing known [Aquinas]
12. Knowledge Sources / A. A Priori Knowledge / 2. Self-Evidence
Some things are self-evident to us; others are only self-evident in themselves [Aquinas]
12. Knowledge Sources / A. A Priori Knowledge / 3. Innate Knowledge / a. Innate knowledge
Initial universal truths are present within us as potential, to be drawn out by reason [Aquinas]
12. Knowledge Sources / A. A Priori Knowledge / 8. A Priori as Analytic
A proposition is self-evident if the predicate is included in the essence of the subject [Aquinas]
12. Knowledge Sources / B. Perception / 3. Representation
Minds take in a likeness of things, which activates an awaiting potential [Aquinas]
12. Knowledge Sources / C. Rationalism / 1. Rationalism
Sensation prepares the way for intellectual knowledge, which needs the virtues of reason [Aquinas]
12. Knowledge Sources / D. Empiricism / 5. Empiricism Critique
Knowledge may be based on senses, but we needn't sense all our knowledge [Aquinas]
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / a. Coherence as justification
The fullest knowledge places a conclusion within an accurate theory [Aquinas, by Kretzmann/Stump]
14. Science / D. Explanation / 2. Types of Explanation / k. Explanations by essence
Definition of essence makes things understandable [Aquinas]
15. Nature of Minds / C. Capacities of Minds / 1. Faculties
Sensations are transmitted to 'internal senses' in the brain, chiefly to 'phantasia' and 'imagination' [Aquinas, by Kretzmann/Stump]
15. Nature of Minds / C. Capacities of Minds / 2. Imagination
Mental activity combines what we sense with imagination of what is not present [Aquinas]
15. Nature of Minds / C. Capacities of Minds / 3. Abstraction by mind
Abstracting A from B generates truth, as long as the connection is not denied [Aquinas]
15. Nature of Minds / C. Capacities of Minds / 5. Generalisation by mind
We understand the general nature of things by ignoring individual peculiarities [Aquinas]
The mind abstracts generalities from images, but also uses images for understanding [Aquinas]
Very general ideas (being, oneness, potentiality) can be abstracted from thought matter in general [Aquinas]
Particular instances come first, and (pace Plato) generalisations are abstracted from them [Aquinas]
Species are abstracted from appearances by ignoring individual conditions [Aquinas]
16. Persons / F. Free Will / 1. Nature of Free Will
Aquinas attributes freedom to decisions and judgements, and not to the will alone [Aquinas, by Kretzmann/Stump]
16. Persons / F. Free Will / 3. Constraints on the will
If we saw something as totally and utterly good, we would be compelled to will it [Aquinas]
16. Persons / F. Free Will / 4. For Free Will
Nothing can be willed except what is good, but good is very varied, and so choices are unpredictable [Aquinas]
However habituated you are, given time to ponder you can go against a habit [Aquinas]
Since will is a reasoning power, it can entertain opposites, so it is not compelled to embrace one of them [Aquinas]
The will is not compelled to move, even if pleasant things are set before it [Aquinas]
Because the will moves by examining alternatives, it doesn't compel itself to will [Aquinas]
16. Persons / F. Free Will / 5. Against Free Will
We must admit that when the will is not willing something, the first movement to will must come from outside the will [Aquinas]
17. Mind and Body / A. Mind-Body Dualism / 1. Dualism
The human intellectual soul is an incorporeal, subsistent principle [Aquinas]
17. Mind and Body / A. Mind-Body Dualism / 4. Occasionalism
Without God's influence every operation would stop, so God causes everything [Aquinas]
18. Thought / A. Modes of Thought / 6. Judgement / a. Nature of Judgement
First grasp what it is, then its essential features; judgement is their compounding and division [Aquinas]
18. Thought / E. Abstraction / 1. Abstract Thought
We abstract forms from appearances, and acquire knowledge of immaterial things [Aquinas]
Understanding consists entirely of grasping abstracted species [Aquinas]
18. Thought / E. Abstraction / 2. Abstracta by Selection
Mathematics can be abstracted from sensible matter, and from individual intelligible matter [Aquinas]
18. Thought / E. Abstraction / 3. Abstracta by Ignoring
Mathematical objects abstract both from perceived matter, and from particular substance [Aquinas]
We can just think of an apple's colour, because the apple is not part of the colour's nature [Aquinas]
Abstracting either treats something as separate, or thinks of it separately [Aquinas]
Numbers and shapes are abstracted by ignoring their sensible qualities [Aquinas]
18. Thought / E. Abstraction / 8. Abstractionism Critique
The mind must produce by its own power an image of the individual species [Aquinas]
19. Language / C. Assigning Meanings / 3. Predicates
The mind constructs complete attributions, based on the unified elements of the real world [Aquinas]
19. Language / E. Analyticity / 1. Analytic Propositions
Sentences are 'analytical' if every sequence of objects models them [Tarski]
20. Action / B. Preliminaries of Action / 2. Willed Action / a. Will to Act
The will must aim at happiness, but can choose the means [Aquinas]
We don't have to will even perfect good, because we can choose not to think of it [Aquinas]
The will can only want what it thinks is good [Aquinas]
The will is the rational appetite [Aquinas]
21. Aesthetics / A. Aesthetic Experience / 3. Taste
Taste is the capacity to judge an object or representation which is thought to be beautiful [Tarski, by Schellekens]
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / g. Moral responsibility
Without free will not only is ethical action meaningless, but also planning, commanding, praising and blaming [Aquinas]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / b. Rational ethics
For humans good is accordance with reason, and bad is contrary to reason [Aquinas]
22. Metaethics / B. Value / 1. Nature of Value / e. Means and ends
We must know the end, know that it is the end, and know how to attain it [Aquinas]
22. Metaethics / C. The Good / 1. Goodness / g. Consequentialism
Good applies to goals, just as truth applies to ideas in the mind [Aquinas]
23. Ethics / A. Egoism / 1. Ethical Egoism
The greatest good is not the achievement of desire, but to desire what is proper [Menedemus, by Diog. Laertius]
23. Ethics / C. Virtue Theory / 1. Virtue Theory / b. Basis of virtue
All acts of virtue relate to justice, which is directed towards the common good [Aquinas]
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / d. Teaching virtue
Aquinas wanted, not to escape desire, but to transform it for moral ends [Aquinas, by MacIntyre]
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / i. Absolute virtues
Legal justice is supreme, because it directs the other virtues to the common good [Aquinas]
23. Ethics / C. Virtue Theory / 3. Virtues / b. Temperance
Temperance prevents our passions from acting against reason [Aquinas]
23. Ethics / C. Virtue Theory / 3. Virtues / c. Justice
Justice directs our relations with others, because it denotes a kind of equality [Aquinas]
25. Social Practice / D. Justice / 1. Basis of justice
People differ in their social degrees, and a particular type of right applies to each [Aquinas]
25. Social Practice / D. Justice / 2. The Law / c. Natural law
Natural law is a rational creature's participation in eternal law [Aquinas]
Right and wrong actions pertain to natural law, as perceived by practical reason [Aquinas]
Tyrannical laws are irrational, and so not really laws [Aquinas]
25. Social Practice / E. Policies / 1. War / a. Just wars
For Aquinas a war must be in a just cause, have proper authority, and aim at good [Aquinas, by Grayling]
25. Social Practice / F. Life Issues / 3. Abortion
Aquinas says a fertilized egg is not human, and has no immortal soul [Aquinas, by Martin/Barresi]
26. Natural Theory / A. Speculations on Nature / 7. Later Matter Theories / c. Matter as extension
Bodies are three-dimensional substances [Aquinas]
26. Natural Theory / C. Causation / 5. Direction of causation
A cause can exist without its effect, but the effect cannot exist without its cause [Aquinas]
26. Natural Theory / C. Causation / 9. General Causation / d. Causal necessity
Even a sufficient cause doesn't compel its effect, because interference could interrupt the process [Aquinas]
27. Natural Reality / D. Time / 1. Nature of Time / f. Eternalism
Eternity coexists with passing time, as the centre of a circle coexists with its circumference [Aquinas]
28. God / A. Divine Nature / 6. Divine Morality / b. Euthyphro question
Divine law commands some things because they are good, while others are good because commanded [Aquinas]
28. God / B. Proving God / 2. Proofs of Reason / b. Ontological Proof critique
We can't know God's essence, so his existence can't be self-evident for us [Aquinas]
28. God / B. Proving God / 3. Proofs of Evidence / a. Cosmological Proof
If you assume that there must be a necessary being, you can't say which being has this quality [Kant on Aquinas]
Way 1: the infinite chain of potential-to-actual movement has to have a first mover [Aquinas]
Way 2: no effect without a cause, and this cannot go back to infinity, so there is First Cause [Aquinas]
Way 3: contingent beings eventually vanish, so continuity needs a necessary being [Aquinas]
Way 4: the source of all qualities is their maximum, so something (God) causes all perfections [Aquinas]
28. God / B. Proving God / 3. Proofs of Evidence / b. Teleological Proof
Way 5: mindless things act towards an obvious end, so there is an intelligent director [Aquinas]
29. Religion / B. Monotheistic Religion / 4. Christianity / a. Christianity
Life aims at the Beatific Vision - of perfect happiness, and revealed truth [Aquinas, by Zagzebski]
29. Religion / B. Monotheistic Religion / 4. Christianity / c. Angels
Aquinas saw angels as separated forms, rather than as made of 'spiritual matter' [Aquinas, by Kretzmann/Stump]
29. Religion / B. Monotheistic Religion / 4. Christianity / d. Heresy
Heretics should be eradicated like wolves [Aquinas]
29. Religion / D. Religious Issues / 2. Immortality / a. Immortality
Humans have a non-physical faculty of reason, so they can be immortal [Aquinas, by Sorabji]
If the soul achieves well-being in another life, it doesn't follow that I do [Aquinas]
29. Religion / D. Religious Issues / 2. Immortality / d. Heaven
Those in bliss have their happiness increased by seeing the damned punished [Aquinas]
29. Religion / D. Religious Issues / 3. Problem of Evil / a. Problem of Evil
God does not exist, because He is infinite and good, and so no evil should be discoverable [Aquinas]
It is part of God's supreme goodness that He brings good even out of evil [Aquinas]