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All the ideas for 'Theaetetus', 'In Praise of Philosophy' and 'Tarski's Theory of Truth'

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43 ideas

1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / d. Philosophy as puzzles
Philosophers are marked by a joint love of evidence and ambiguity [Merleau-Ponty]
     Full Idea: The philosopher is marked by the distinguishing trait that he possesses inseparably the taste for evidence and the feeling for ambiguity.
     From: Maurice Merleau-Ponty (In Praise of Philosophy [1953], p.4), quoted by Sarah Bakewell - At the Existentialist Café 11
     A reaction: I strongly approve of the idea that philosophers are primarily interested in evidence (rather than reason or logic), and I also like the idea that the ambiguous evidence is the most interesting. The mind looks physical and non-physical.
1. Philosophy / D. Nature of Philosophy / 7. Despair over Philosophy
Philosophers are always switching direction to something more interesting [Plato]
     Full Idea: Philosophers are always ready to change direction, if a topic crops up which is more attractive than the one to hand.
     From: Plato (Theaetetus [c.368 BCE], 172d)
     A reaction: Which sounds trivial, but it may be what God does.
1. Philosophy / F. Analytic Philosophy / 2. Analysis by Division
Understanding mainly involves knowing the elements, not their combinations [Plato]
     Full Idea: A perfect grasp of any subject depends far more on knowing elements than on knowing complexes.
     From: Plato (Theaetetus [c.368 BCE], 206b)
Either a syllable is its letters (making parts as knowable as whole) or it isn't (meaning it has no parts) [Plato]
     Full Idea: Either a syllable is not the same as its letters, in which case it cannot have the letters as parts of itself, or it is the same as its letters, in which case these basic elements are just as knowable as it is.
     From: Plato (Theaetetus [c.368 BCE], 205b)
2. Reason / A. Nature of Reason / 6. Coherence
A rational account is essentially a weaving together of things with names [Plato]
     Full Idea: Just as primary elements are woven together, so their names may be woven together to produce a spoken account, because an account is essentially a weaving together of names.
     From: Plato (Theaetetus [c.368 BCE], 202b)
     A reaction: If justification requires 'logos', and logos is a 'weaving together of names', then Plato might be taken as endorsing the coherence account of justification. Or do the two 'weavings' correspond?
2. Reason / C. Styles of Reason / 3. Eristic
Eristic discussion is aggressive, but dialectic aims to help one's companions in discussion [Plato]
     Full Idea: Eristic discussions involve as many tricks and traps as possible, but dialectical discussions involve being serious and correcting the interlocutor's mistakes only when they are his own fault or the result of past conditioning.
     From: Plato (Theaetetus [c.368 BCE], 167e)
2. Reason / D. Definition / 4. Real Definition
A primary element has only a name, and no logos, but complexes have an account, by weaving the names [Plato]
     Full Idea: A primary element cannot be expressed in an account; it can only be named, for a name is all that it has. But with the things composed of these ...just as the elements are woven together, so the names can woven to become an account.
     From: Plato (Theaetetus [c.368 BCE], 202b01-3)
     A reaction: This is the beginning of what I see as Aristotle's metaphysics, as derived from his epistemology, that is, ontology is what explains, and what we can give an account [logos] of. Aristotle treats this under 'definitions'.
3. Truth / A. Truth Problems / 4. Uses of Truth
The notion of truth is to help us make use of the utterances of others [Field,H]
     Full Idea: I suspect that the original purpose of the notion of truth was to aid us in utilizing the utterances of others in drawing conclusions about the world,...so we must attend to its social role, and that being in a position to assert something is what counts.
     From: Hartry Field (Tarski's Theory of Truth [1972], §5)
     A reaction: [Last bit compressed] This sounds excellent. Deflationary and redundancy views are based on a highly individualistic view of utterances and truth, but we need to be much more contextual and pragmatic if we are to get the right story.
3. Truth / A. Truth Problems / 9. Rejecting Truth
In the early 1930s many philosophers thought truth was not scientific [Field,H]
     Full Idea: In the early 1930s many philosophers believed that the notion of truth could not be incorporated into a scientific conception of the world.
     From: Hartry Field (Tarski's Theory of Truth [1972], §3)
     A reaction: This leads on to an account of why Tarski's formal version was so important, and Field emphasises Tarski's physicalist metaphysic.
3. Truth / F. Semantic Truth / 1. Tarski's Truth / a. Tarski's truth definition
Tarski reduced truth to reference or denotation [Field,H, by Hart,WD]
     Full Idea: Tarski can be viewed as having reduced truth to reference or denotation.
     From: report of Hartry Field (Tarski's Theory of Truth [1972]) by William D. Hart - The Evolution of Logic 4
Tarski really explained truth in terms of denoting, predicating and satisfied functions [Field,H]
     Full Idea: A proper account of Tarski's truth definition explains truth in terms of three other semantic notions: what it is for a name to denote something, and for a predicate to apply to something, and for a function symbol to be fulfilled by a pair of things.
     From: Hartry Field (Tarski's Theory of Truth [1972])
     A reaction: This is Field's 'T1' version, which is meant to spell out what was really going on in Tarski's account.
3. Truth / F. Semantic Truth / 1. Tarski's Truth / b. Satisfaction and truth
Tarski just reduced truth to some other undefined semantic notions [Field,H]
     Full Idea: It is normally claimed that Tarski defined truth using no undefined semantic terms, but I argue that he reduced the notion of truth to certain other semantic notions, but did not in any way explicate these other notions.
     From: Hartry Field (Tarski's Theory of Truth [1972], §0)
5. Theory of Logic / I. Semantics of Logic / 2. Formal Truth
Tarski gives us the account of truth needed to build a group of true sentences in a model [Field,H]
     Full Idea: Model theory must choose the denotations of the primitives so that all of a group of sentences come out true, so we need a theory of how the truth value of a sentence depends on the denotation of its primitive nonlogical parts, which Tarski gives us.
     From: Hartry Field (Tarski's Theory of Truth [1972], §1)
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
Model theory is unusual in restricting the range of the quantifiers [Field,H]
     Full Idea: In model theory we are interested in allowing a slightly unusual semantics for quantifiers: we are willing to allow that the quantifier not range over everything.
     From: Hartry Field (Tarski's Theory of Truth [1972], n 5)
6. Mathematics / C. Sources of Mathematics / 1. Mathematical Platonism / a. For mathematical platonism
We master arithmetic by knowing all the numbers in our soul [Plato]
     Full Idea: It must surely be true that a man who has completely mastered arithmetic knows all numbers? Because there are pieces of knowledge covering all numbers in his soul.
     From: Plato (Theaetetus [c.368 BCE], 198b)
     A reaction: This clearly views numbers as objects. Expectation of knowing them all is a bit startling! They also appear to be innate in us, and hence they appear to be Forms. See Aristotle's comment in Idea 645.
7. Existence / B. Change in Existence / 1. Nature of Change
There seem to be two sorts of change: alteration and motion [Plato]
     Full Idea: There are two kinds of change, I think: alteration and motion.
     From: Plato (Theaetetus [c.368 BCE], 181d)
9. Objects / C. Structure of Objects / 8. Parts of Objects / a. Parts of objects
If a word has no parts and has a single identity, it turns out to be the same kind of thing as a letter [Plato]
     Full Idea: If a complex or a syllable has no parts and is a single identity, hasn't it turned out to be the same kind of thing as an element or letter?
     From: Plato (Theaetetus [c.368 BCE], 205d)
9. Objects / C. Structure of Objects / 8. Parts of Objects / c. Wholes from parts
A sum is that from which nothing is lacking, which is a whole [Plato]
     Full Idea: But this sum now - isn't it just when there is nothing lacking that it is a sum? Yes, necessarily. And won't this very same thing - that from which nothing is lacking - be a whole?
     From: Plato (Theaetetus [c.368 BCE], 205a)
     A reaction: This seems to be right, be rather too vague and potentially circular to be of much use. What is the criterion for deciding that nothing is lacking?
The whole can't be the parts, because it would be all of the parts, which is the whole [Plato]
     Full Idea: The whole does not consist of parts; for it did, it would be all the parts and so would be the sum.
     From: Plato (Theaetetus [c.368 BCE], 204e)
     A reaction: That is, 'the whole is the sum of its parts' is a tautology! The claim that 'the whole is more than the sum of its parts' gets into similar trouble. See Verity Harte on this.
11. Knowledge Aims / A. Knowledge / 1. Knowledge
Things are only knowable if a rational account (logos) is possible [Plato]
     Full Idea: Things which are susceptible to a rational account are knowable.
     From: Plato (Theaetetus [c.368 BCE], 201d)
11. Knowledge Aims / A. Knowledge / 2. Understanding
Expertise is knowledge of the whole by means of the parts [Plato]
     Full Idea: A man has passed from mere judgment to expert knowledge of the being of a wagon when he has done so in virtue of having gone over the whole by means of the elements.
     From: Plato (Theaetetus [c.368 BCE], 207c)
     A reaction: Plato is emphasising that the expert must know the hundred parts of a wagon, and not just the half dozen main components, but here the point is to go over the whole via the parts, and not just list the parts.
11. Knowledge Aims / A. Knowledge / 4. Belief / c. Aim of beliefs
It is impossible to believe something which is held to be false [Plato]
     Full Idea: It is impossible to believe something which is not the case.
     From: Plato (Theaetetus [c.368 BCE], 167a)
11. Knowledge Aims / A. Knowledge / 4. Belief / d. Cause of beliefs
How can a belief exist if its object doesn't exist? [Plato]
     Full Idea: If the object of a belief is what is not, the object of this belief is nothing; but if there is no object to a belief, then that is not belief at all.
     From: Plato (Theaetetus [c.368 BCE], 189a)
12. Knowledge Sources / B. Perception / 1. Perception
Perception is infallible, suggesting that it is knowledge [Plato]
     Full Idea: Perception is always of something that is, and it is infallible, which suggests that it is knowledge.
     From: Plato (Theaetetus [c.368 BCE], 152c)
Our senses could have been separate, but they converge on one mind [Plato]
     Full Idea: It would be peculiar if each of us were like a Trojan horse, with a whole bunch of senses sitting inside us, rather than that all these perceptions converge onto a single identity (mind, or whatever one ought to call it).
     From: Plato (Theaetetus [c.368 BCE], 184d)
12. Knowledge Sources / C. Rationalism / 1. Rationalism
With what physical faculty do we perceive pairs of opposed abstract qualities? [Plato]
     Full Idea: With what physical faculty do we perceive being and not-being, similarity and dissimilarity, identity and difference, oneness and many, odd and even and other maths, ….fineness and goodness?
     From: Plato (Theaetetus [c.368 BCE], 185d)
You might mistake eleven for twelve in your senses, but not in your mind [Plato]
     Full Idea: Sight or touch might make someone take eleven for twelve, but he could never form this mistaken belief about the contents of his mind.
     From: Plato (Theaetetus [c.368 BCE], 195e)
Thought must grasp being itself before truth becomes possible [Plato]
     Full Idea: If you can't apprehend being you can't apprehend truth, and so a thing could not be known. Therefore knowledge is not located in immediate experience but in thinking about it, since the latter makes it possible to grasp being and truth.
     From: Plato (Theaetetus [c.368 BCE], 186c)
13. Knowledge Criteria / A. Justification Problems / 1. Justification / b. Need for justification
An inadequate rational account would still not justify knowledge [Plato]
     Full Idea: If you don't know which letters belong together in the right syllables…it is possible for true belief to be accompanied by a rational account and still not be entitled to the name of knowledge.
     From: Plato (Theaetetus [c.368 BCE], 208b)
     A reaction: In each case of justification there is a 'clinching' stage, for which there is never going to be a strict rule. It might be foundational, but equally it might be massive coherence, or no alternative.
13. Knowledge Criteria / A. Justification Problems / 2. Justification Challenges / a. Agrippa's trilemma
Parts and wholes are either equally knowable or equally unknowable [Plato]
     Full Idea: Either a syllable and its letters are equally knowable and expressible in a rational account, or they are both equally unknowable and inexpressible.
     From: Plato (Theaetetus [c.368 BCE], 205e)
     A reaction: Presumably you could explain the syllable by the letters, but not vice versa, but he must mean that the explanation is worthless without the letters being explained too. So all explanation is worthless?
Without distinguishing marks, how do I know what my beliefs are about? [Plato]
     Full Idea: If I only have beliefs about Theaetetus when I don't know his distinguishing mark, how on earth were my beliefs about you rather than anyone else?
     From: Plato (Theaetetus [c.368 BCE], 209b)
     A reaction: This is a rather intellectualist approach to mental activity. Presumably Theaetetus has lots of distinguishing marks, but they are not conscious. Must Socrates know everything?
13. Knowledge Criteria / A. Justification Problems / 3. Internal or External / a. Pro-internalism
A rational account might be seeing an image of one's belief, like a reflection in a mirror [Plato]
     Full Idea: A rational account might be forming an image of one's belief, as in a mirror or a pond.
     From: Plato (Theaetetus [c.368 BCE], 206d)
     A reaction: Not promising, since the image is not going to be clearer than the original, or contain any new information. Maybe it would be clarified by being 'framed', instead of drifting in muddle.
A rational account involves giving an image, or analysis, or giving a differentiating mark [Plato]
     Full Idea: A third sort of rational account (after giving an image, or analysing elements) is being able to mention some mark which differentiates the object in question ('the sun is the brightest heavenly body').
     From: Plato (Theaetetus [c.368 BCE], 208c)
     A reaction: This is Plato's clearest statement of what would be involved in adding the necessary logos to your true belief. An image of it, or an analysis, or an individuation. How about a cause?
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / a. Foundationalism
Maybe primary elements can be named, but not receive a rational account [Plato]
     Full Idea: Maybe the primary elements of which things are composed are not susceptible to rational accounts. Each of them taken by itself can only be named, but nothing further can be said about it.
     From: Plato (Theaetetus [c.368 BCE], 201e)
     A reaction: This still seems to be more or less the central issue in philosophy - which things should be treated as 'primitive', and which other things are analysed and explained using the primitive tools?
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / b. Pro-coherentism
A rational account of a wagon would mean knowledge of its hundred parts [Plato]
     Full Idea: In the case of a wagon, we may only have correct belief, but someone who is able to explain what it is by going through its hundred parts has got hold of a rational account.
     From: Plato (Theaetetus [c.368 BCE], 207b)
     A reaction: A wonderful example. In science, you know smoking correlates with cancer, but you only know it when you know the mechanism, the causal structure. This may be a general truth.
13. Knowledge Criteria / D. Scepticism / 5. Dream Scepticism
What evidence can be brought to show whether we are dreaming or not? [Plato]
     Full Idea: What evidence could be brought if we were asked at this very moment whether we are asleep and are dreaming all our thoughts?
     From: Plato (Theaetetus [c.368 BCE], 158b)
13. Knowledge Criteria / E. Relativism / 6. Relativism Critique
If you claim that all beliefs are true, that includes beliefs opposed to your own [Plato]
     Full Idea: To say that everyone believes what is the case, is to concede the truth of the oppositions' beliefs; in other words, the person has to concede that he himself is wrong.
     From: Plato (Theaetetus [c.368 BCE], 171a)
How can a relativist form opinions about what will happen in the future? [Plato]
     Full Idea: Does a relativist have any authority to decide about things which will happen in the future?
     From: Plato (Theaetetus [c.368 BCE], 178c)
     A reaction: Nice question! It seems commonsense that such speculations are possible, but without a concept of truth they are ridiculous.
Clearly some people are superior to others when it comes to medicine [Plato]
     Full Idea: In medicine, at least, most people are not self-sufficient at prescribing and effecting cures for themselves, and here some people are superior to others.
     From: Plato (Theaetetus [c.368 BCE], 171e)
17. Mind and Body / E. Mind as Physical / 2. Reduction of Mind
'Valence' and 'gene' had to be reduced to show their compatibility with physicalism [Field,H]
     Full Idea: 'Valence' and 'gene' were perfectly clear long before anyone succeeded in reducing them, but it was their reducibility and not their clarity before reduction that showed them to be compatible with physicalism.
     From: Hartry Field (Tarski's Theory of Truth [1972], §5)
19. Language / B. Reference / 3. Direct Reference / b. Causal reference
Field says reference is a causal physical relation between mental states and objects [Field,H, by Putnam]
     Full Idea: In Field's view reference is a 'physicalistic relation', i.e. a complex causal relation between words or mental representations and objects or sets of objects; it is up to physical science to discover what that physicalistic relation is.
     From: report of Hartry Field (Tarski's Theory of Truth [1972]) by Hilary Putnam - Reason, Truth and History Ch.2
     A reaction: I wouldn't hold your breath while the scientists do their job. If physicalism is right then Field is right, but physics seems no more appropriate for giving a theory of reference than it does for giving a theory of music.
28. God / A. Divine Nature / 6. Divine Morality / c. God is the good
God must be the epitome of goodness, and we can only approach a divine state by being as good as possible [Plato]
     Full Idea: It is impossible for God to be immoral and not to be the acme of morality; and the only way any of us can approximate to God is to become as moral as possible.
     From: Plato (Theaetetus [c.368 BCE], 176c)
29. Religion / D. Religious Issues / 3. Problem of Evil / a. Problem of Evil
There must always be some force of evil ranged against good [Plato]
     Full Idea: The elimination of evil is impossible, Theodorus; there must always be some force ranged against good.
     From: Plato (Theaetetus [c.368 BCE], 176a)