Ideas of Stephen Yablo, by Theme

[American, fl. 1996, Student of Donald Davidson. Professor at the Massachusetts Institute of Technology.]

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3. Truth / A. Truth Problems / 5. Truth Bearers
A statement S is 'partly true' if it has some wholly true parts
     Full Idea: A statement S is 'partly true' insofar as it has wholly true parts: wholly true implications whose subject matter is included in that of S.
     From: Stephen Yablo (Aboutness [2014], 01.6)
     A reaction: He suggests that if we have rival theories, we agree that it is one or the other. And 'we may have pork for dinner, or human flesh' is partly true.
4. Formal Logic / A. Syllogistic Logic / 2. Syllogistic Logic
An 'enthymeme' is an argument with an indispensable unstated assumption
     Full Idea: An 'enthymeme' is a deductive argument with an unstated assumption that must be true for the premises to lead to the conclusion.
     From: Stephen Yablo (Aboutness [2014], 11.1)
4. Formal Logic / D. Modal Logic ML / 4. Alethic Modal Logic
The main modal logics disagree over three key formulae
     Full Idea: Lewis's different systems of modal logic differed about such formulae as □P implies □□P; ◊□P implies □P; and ◊S implies □◊S
     From: Stephen Yablo (Apriority and Existence [2000], 06)
     A reaction: Yablo's point is that the various version don't seem to make much difference to our practices in logic, mathematics and science. The problem, says Yablo, is deciding exactly what you mean by 'necessarily' and 'possibly'.
4. Formal Logic / G. Formal Mereology / 3. Axioms of Mereology
y is only a proper part of x if there is a z which 'makes up the difference' between them
     Full Idea: The principle of Supplementation says that y is properly part of x, only if a z exists that 'makes up the difference' between them. [note: that is, z is disjoint from y and sums with y to form x]
     From: Stephen Yablo (Aboutness [2014], 03.2)
5. Theory of Logic / F. Referring in Logic / 1. Naming / e. Empty names
'Pegasus doesn't exist' is false without Pegasus, yet the absence of Pegasus is its truthmaker
     Full Idea: 'Pegasus does not exist' has a paradoxical, self-undermining flavour. On the one hand, the empty name makes it untrue. But now, why is the name empty? Because Pegasus does not exist. 'Pegasus does not exist' is untrue because Pegasus does not exist.
     From: Stephen Yablo (Aboutness [2014], 05.7 n20)
     A reaction: Beautiful! This is Yablo's reward for continuing to ask 'why?' after everyone else has stopped in bewilderment at the tricky phenomenon.
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / a. The Liar paradox
An infinite series of sentences asserting falsehood produces the paradox without self-reference
     Full Idea: Banning self-reference is too narrow to avoid the liar paradox. With 1) all the subsequent sentences are false, 2) all the subsequent sentences are false, 3) all the subsequent... the paradox still arises. Self-reference is a special case of this.
     From: report of Stephen Yablo (Paradox without Self-Reference [1993]) by Roy Sorensen - Vagueness and Contradiction 11.1
     A reaction: [Idea 9137 pointed out that the ban was too narrow. Sorensen p.168 explains why this one is paradoxical] This is a nice example of progress in philosophy, since the Greeks would have been thrilled with this idea (unless they knew it, but it was lost).
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / a. Numbers
If 'the number of Democrats is on the rise', does that mean that 50 million is on the rise?
     Full Idea: If someone says 'the number of Democrats is on the rise', he or she wants to focus on Democrats, not numbers. If the number is 50 million, is 50 million really on the rise?
     From: Stephen Yablo (Apriority and Existence [2000], 14)
     A reaction: This is a very nice warning from Yablo, against easy platonism, or any sort of platonism at all. We routinely say that numbers are 'increasing', but the real meaning needs entangling. Here it refers to people joining a party.
6. Mathematics / C. Sources of Mathematics / 3. Mathematical Nominalism
A nominalist can assert statements about mathematical objects, as being partly true
     Full Idea: If I am a nominalist non-Platonist, I think it is false that 'there are primes over 10', but I want to be able to say it like everyone else. I argue that this because the statement has a part that I do believe, a part that remains interestingly true.
     From: Stephen Yablo (Aboutness [2014], 05.8)
     A reaction: This is obviously a key motivation for Yablo's book, as it reinforces his fictional view of abstract objects, but aims to capture the phenomena, by investigating what such sentences are 'about'. Admirable.
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / b. Indispensability of mathematics
We must treat numbers as existing in order to express ourselves about the arrangement of planets
     Full Idea: It is only by making as if to countenance numbers that one can give expression in English to a fact having nothing to do with numbers, a fact about stars and planets and how they are numerically proportioned.
     From: Stephen Yablo (Apriority and Existence [2000], 13)
     A reaction: To avoid the phrase 'numerically proportioned', he might have alluded to the 'pattern' of the stars and planets. I'm not sure which -ism this is, but it seems to me a good approach. The application is likely to precede the theory.
6. Mathematics / C. Sources of Mathematics / 6. Logicism / c. Neo-logicism
Mathematics is both necessary and a priori because it really consists of logical truths
     Full Idea: Mathematics seems necessary because the real contents of mathematical statements are logical truths, which are necessary, and it seems a priori because logical truths really are a priori.
     From: Stephen Yablo (Abstract Objects: a Case Study [2002], 10)
     A reaction: Yablo says his logicism has a Kantian strain, because numbers and sets 'inscribed on our spectacles', but he takes a different view (in the present Idea) from Kant about where the necessity resides. Personally I am tempted by an a posteriori necessity.
6. Mathematics / C. Sources of Mathematics / 9. Fictional Mathematics
Platonic objects are really created as existential metaphors
     Full Idea: The means by which platonic objects are simulated is existential metaphor. Numbers are conjured up as metaphorical measures of cardinality.
     From: Stephen Yablo (Apriority and Existence [2000], 12)
     A reaction: 'Fictional' might be a better word than 'metaphorical', since the latter usually implies some sort of comparison.
Putting numbers in quantifiable position (rather than many quantifiers) makes expression easier
     Full Idea: Saying 'the number of Fs is 5', instead of using five quantifiers, puts the numeral in quantifiable position, which brings expressive advantages. 'There are more sheep in the field than cows' is an infinite disjunction, expressible in finite compass.
     From: Stephen Yablo (Abstract Objects: a Case Study [2002], 08)
     A reaction: See Hofweber with similar thoughts. This idea I take to be a key one in explaining many metaphysical confusions. The human mind just has a strong tendency to objectify properties, relations, qualities, categories etc. - for expression and for reasoning.
7. Existence / C. Structure of Existence / 7. Abstract/Concrete / a. Abstract/concrete
Concrete objects have few essential properties, but properties of abstractions are mostly essential
     Full Idea: Objects like me have a few essential properties, and numerous accidental ones. Abstract objects are a different story. The intrinsic properties of the empty set are mostly essential. The relations of numbers are also mostly essential.
     From: Stephen Yablo (Abstract Objects: a Case Study [2002], 01)
We are thought to know concreta a posteriori, and many abstracta a priori
     Full Idea: Our knowledge of concreta is a posteriori, but our knowledge of numbers, at least, has often been considered a priori.
     From: Stephen Yablo (Abstract Objects: a Case Study [2002], 02)
7. Existence / D. Theories of Reality / 6. Fictionalism
For me, fictions are internally true, without a significant internal or external truth-value
     Full Idea: A 'myth' or fiction for me is a true internal statement (a statement endorsed by the rules) whose external truth value is as may be, the point being that that truth value is from an internal standpoint quite irrelevant.
     From: Stephen Yablo (Does Ontology Rest on a Mistake? [1998], IX)
     A reaction: This contrasts with Carnap, for whom talk of 'ghosts' is false in an internal thing-framework. Yablo seems here to say a statement can be true while having no truth value. Presumably he is relaxing the internal rules.
Make-believe can help us to reason about facts and scientific procedures
     Full Idea: Make-believe games can make it easier to reason about facts, to systematize them, to visualize them, to spot connections with other facts, and to evaluate potential lines of research.
     From: Stephen Yablo (Does Ontology Rest on a Mistake? [1998], XI)
     A reaction: This is the key pragmatic defence of the fictionalist view of abstract objects. Fictions are devices to help us think better. I think a lot of ontology turns out that way.
'The clouds are angry' can only mean '...if one were attributing emotions to clouds'
     Full Idea: It is an open question whether the clouds that we call 'angry' are literally F, for any F other than 'such that it would be natural and proper to regard them as angry if one were going to attribute emotions to clouds'.
     From: Stephen Yablo (Does Ontology Rest on a Mistake? [1998], XII)
     A reaction: His point is that it is TRUE, in those circumstances, that the clouds are angry. Thus fictions are a valid and useful part of ordinary sensible course, giving real information. I like it.
We quantify over events, worlds, etc. in order to make logical possibilities clearer
     Full Idea: It is not that the contents of sentences are inexpressible without quantifying over events, worlds, etc. (they aren't). But the logical relations become much more tractable if we represent them quantificationally.
     From: Stephen Yablo (Apriority and Existence [2000], 13)
     A reaction: Yablo is explaining why we find ourselves committed to abstract objects. It is essentially, as I am beginning to suspect, a conspiracy of logicians. What on earth is 'the empty set' when it is at home? What's it made of?
Fictionalism allows that simulated beliefs may be tracking real facts
     Full Idea: The fictionalist offers the option that your simulated beliefs and assertions may be tracking a realm of genuine facts, or a realm of what you take to be facts.
     From: Stephen Yablo (Go Figure: a Path through Fictionalism [2001], 13)
     A reaction: This means that fictionalism does not have to be an error theory. That is, we aren't mistakenly believing something that we actually made up. Instead we are sensibly believing something we know to be not literally true. Love it.
8. Modes of Existence / E. Nominalism / 1. Nominalism / c. Nominalism about abstracta
Philosophers keep finding unexpected objects, like models, worlds, functions, numbers, events, sets, properties
     Full Idea: There's a tradition in philosophy of finding 'unexpected objects' in truth-conditions, such as countermodels, possible worlds, functions, numbers, events, sets and properties.
     From: Stephen Yablo (Apriority and Existence [2000], 02)
     A reaction: This is a very nice perspective on the whole matter of abstract objects. If we find ourselves reluctantly committed to the existence of something which is ontologically peculiar, we should go back to the philosophical drawing-board.
9. Objects / B. Unity of Objects / 3. Unity Problems / c. Statue and clay
A statue is essentially the statue, but its lump is not essentially a statue, so statue isn't lump
     Full Idea: Yablo proposes the argument that Statue A is essentially a statue, and Lump 1 is not essentially a statue, so Statue A is not identical with Lump 1.
     From: report of Stephen Yablo (Identity, Essence and Indiscernibility [1987]) by Michael della Rocca - Essentialists and Essentialism I
     A reaction: Della Rocca and Yablo unashamedly elide necessary properties with essential properties, so this argument doesn't bother me too much. It concerns the statue and the clay having different modal properties.
9. Objects / C. Structure of Objects / 8. Parts of Objects / a. Parts of objects
Parthood lacks the restriction of kind which most relations have
     Full Idea: Most relations obtain only between certain kinds of thing. To learn that x is a part of y, however, tells you nothing about x and y taken individually.
     From: Stephen Yablo (Aboutness [2014], 03.2)
     A reaction: Too sweeping. To be a part of crowd you have to be a person. To be part of the sea you have to be wet. It might depend on whether composition is unrestricted.
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / b. Worlds as fictions
Governing possible worlds theory is the fiction that if something is possible, it happens in a world
     Full Idea: The governing fiction of possible worlds theory says that whenever something is possible, there is a world where it happens.
     From: Stephen Yablo (Go Figure: a Path through Fictionalism [2001], 05)
     A reaction: This sounds like the only sensible attitude to possible worlds I can think of.
13. Knowledge Criteria / A. Justification Problems / 2. Justification Challenges / b. Gettier problem
Gettier says you don't know if you are confused about how it is true
     Full Idea: We know from Gettier that if you are right to regard Q as true, but you are sufficiently confused about HOW it is true - about how things stand with respect to its subject matter - then you don't know that Q.
     From: Stephen Yablo (Aboutness [2014], 07.4)
     A reaction: I'm inclined to approach Gettier by focusing on the propositions being expressed, where his cases tend to focus on the literal wording of the sentences. What did the utterer mean by the sentences - not what did they appear to say.
14. Science / B. Scientific Theories / 2. Aim of Science
A theory need not be true to be good; it should just be true about its physical aspects
     Full Idea: A physical theory need not be true to be good, Field has argued, and I agree. All we ask of it truth-wise is that its physical implications should be true, or, in my version, that it should be true about the physical.
     From: Stephen Yablo (Aboutness [2014], 12.5)
     A reaction: Yablo is, of course, writing a book here about the concept of 'about'. This seems persuasive. The internal terminology of the theory isn't committed to anything - it is only at its physical periphery (Quine) that the ontology matters.
14. Science / C. Induction / 5. Paradoxes of Induction / b. Raven paradox
If sentences point to different evidence, they must have different subject-matter
     Full Idea: 'All crows are black' cannot say quite the same as 'All non-black things are non-crows', for the two are confirmed by different evidence. Subject matter looks to be the distinguishing feature. One is about crows, the other not.
     From: Stephen Yablo (Aboutness [2014], Intro)
     A reaction: You might reply that they are confirmed by the same evidence (but only in its unobtainable totality). The point, I think, is that the sentences invite you to start your search in different places.
Most people say nonblack nonravens do confirm 'all ravens are black', but only a tiny bit
     Full Idea: The standard response to the raven paradox is to say that a nonblack nonraven does confirm that all ravens are black. But it confirms it just the teeniest little bit - not as much as a black raven does.
     From: Stephen Yablo (Aboutness [2014], 06.5)
     A reaction: It depends on the proportion between the relevant items. How do you confirm 'all the large animals in this zoo are mammals'? Check for size every animal which is obviously not a mammal?
18. Thought / E. Abstraction / 7. Abstracta by Equivalence
A sentence should be recarved to reveal its content or implication relations
     Full Idea: A sentence invites recarving iff it will then do better justice to the internal structure of its content and/or its implication relations.
     From: Stephen Yablo (Carving Content at the Joints [2002], 11)
     A reaction: This invites human intervention in a logical process (by choosing which recarvings to do, instead of allowing all equivalences to generate them). He seems to think we should abstract in order to reveal logical form.
19. Language / A. Nature of Meaning / 4. Meaning as Truth-Conditions
Sentence-meaning is the truth-conditions - plus factors responsible for them
     Full Idea: A sentence's meaning is to do with its truth-value in various possible scenarios, AND the factors responsible for that truth-value.
     From: Stephen Yablo (Aboutness [2014], Intro)
     A reaction: The thesis of his book, which I welcome. I'm increasingly struck by the way in which much modern philosophy settles for a theory being complete, when actually further explanation is possible. Exhibit A is functional explanations. Why that function?
19. Language / C. Assigning Meanings / 4. Compositionality
The content of an assertion can be quite different from compositional content
     Full Idea: Assertive content - what a sentence is heard as saying - can be at quite a distance from compositional content.
     From: Stephen Yablo (Aboutness [2014], Intro)
     A reaction: This is the obvious reason why semantics cannot be entirely compositional, since there is nearly always a contextual component which then has to be added. In the case of irony, the compositional content is entirely reversed.
19. Language / C. Assigning Meanings / 6. Truth-Conditions Semantics
Truth-conditions as subject-matter has problems of relevance, short cut, and reversal
     Full Idea: If the subject-matter of S is how it is true, we get three unfortunate results: S has truth-value in worlds where its subject-matter draws a blank; learning what S is about tells you its truth-value; negating S changes what it's about.
     From: Stephen Yablo (Aboutness [2014], 02.8)
     A reaction: Together these make fairly devastating objections to the truth-conditions (in possible worlds) theory of meaning. The first-objection concerns when S is false
19. Language / F. Communication / 3. Denial
Not-A is too strong to just erase an improper assertion, because it actually reverses A
     Full Idea: The idea that negation is, or can be, a cancellation device raises an interesting question. What does one do to wipe the slate clean after an improper assertion? Not-A is too strong; it reverses our stand on A rather than nullifying it.
     From: Stephen Yablo (Aboutness [2014], 09.8)
     A reaction: [He is discussing a remark of Strawson 1952] It seems that 'not' has two meanings or uses: a weak use of 'nullifying' an assertion, and a strong use of 'reversing' an assertion. One could do both: 'that's not right; in fact, it's just the opposite'.
19. Language / F. Communication / 6. Interpreting Language / d. Metaphor
Hardly a word in the language is devoid of metaphorical potential
     Full Idea: There is hardly a word in the language - be it an adverb, preposition, conjunction, or what have you - that is devoid of metaphorical potential.
     From: Stephen Yablo (Apriority and Existence [2000], 12)
     A reaction: Yablo goes on to claim that metaphor is at the heart of all of our abstract thinking. 'Dead metaphors' (like the "mouth" of a river) sink totally into literal language. I think Yablo is on the right lines.