Ideas of David Lewis, by Theme

[American, 1941 - 2001, Pupil of Willard Quine. Professor at Princeton University.]

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1. Philosophy / D. Nature of Philosophy / 4. Aims of Philosophy / a. Philosophy as worldly
Honesty requires philosophical theories we can commit to with our ordinary commonsense
1. Philosophy / F. Analytic Philosophy / 1. Analysis
Armstrong's analysis seeks truthmakers rather than definitions
Analysis reduces primitives and makes understanding explicit (without adding new knowledge)
1. Philosophy / F. Analytic Philosophy / 2. Conceptual Analysis
In addition to analysis of a concept, one can deny it, or accept it as primitive
2. Reason / D. Definition / 1. Definitions
Interdefinition is useless by itself, but if we grasp one separately, we have them both
2. Reason / D. Definition / 2. Aims of Definition
Defining terms either enables elimination, or shows that they don't require elimination
2. Reason / E. Argument / 1. Argument
Arguments are nearly always open to challenge, but they help to explain a position rather than force people to believe
3. Truth / A. Truth Problems / 5. Truth Bearers
To be true a sentence must express a proposition, and not be ambiguous or vague or just expressive
3. Truth / A. Truth Problems / 6. Verisimilitude
Verisimilitude might be explained as being close to the possible world where the truth is exact
Verisimilitude has proved hard to analyse, and seems to have several components
3. Truth / B. Truthmakers / 2. Truthmaker Relation
Truthmakers are about existential grounding, not about truth
3. Truth / B. Truthmakers / 5. What Makes Truths / a. What makes truths
Predications aren't truth because of what exists, but of how it exists
3. Truth / B. Truthmakers / 5. What Makes Truths / d. Being makes truths
Say 'truth is supervenient on being', but construe 'being' broadly
3. Truth / B. Truthmakers / 6. Making Negative Truths
If it were true that nothing at all existed, would that have a truthmaker?
3. Truth / B. Truthmakers / 9. Making Past Truths
Presentism says only the present exists, so there is nothing for tensed truths to supervene on
3. Truth / B. Truthmakers / 11. Truthmaking and Correspondence
Truthmaker is correspondence, but without the requirement to be one-to-one
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / g. System S4
If what is actual might have been impossible, we need S4 modal logic
4. Formal Logic / D. Modal Logic ML / 4. Alethic Modal Logic
For modality Lewis rejected boxes and diamonds, preferring worlds, and an index for the actual one
4. Formal Logic / F. Set Theory ST / 1. Set Theory
Sets are mereological sums of the singletons of their members
We can build set theory on singletons: classes are then fusions of subclasses, membership is the singleton
Mathematics reduces to set theory, which reduces, with some mereology, to the singleton function
4. Formal Logic / F. Set Theory ST / 2. Mechanics of Set Theory / b. Terminology of ST
Classes divide into subclasses in many ways, but into members in only one way
A subclass of a subclass is itself a subclass; a member of a member is not in general a member
4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set
We needn't accept this speck of nothingness, this black hole in the fabric of Reality!
The null set is not a little speck of sheer nothingness, a black hole in Reality
We can accept the null set, but there is no null class of anything
There are four main reasons for asserting that there is an empty set
We can accept the null set, but not a null class, a class lacking members
The null set plays the role of last resort, for class abstracts and for existence
4. Formal Logic / F. Set Theory ST / 3. Types of Set / c. Unit (Singleton) Set
We can replace the membership relation with the member-singleton relation (plus mereology)
If we don't understand the singleton, then we don't understand classes
If a set is 'a many thought of as one', beginners should protest against singleton sets
If singleton membership is external, why is an object a member of one rather than another?
Maybe singletons have a structure, of a thing and a lasso?
What on earth is the relationship between a singleton and an element?
Are all singletons exact intrinsic duplicates?
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
Set theory has some unofficial axioms, generalisations about how to understand it
Set theory reduces to a mereological theory with singletons as the only atoms
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / a. Sets as existing
If singletons are where their members are, then so are all sets
A huge part of Reality is only accepted as existing if you have accepted set theory
Set theory isn't innocent; it generates infinities from a single thing; but mathematics needs it
4. Formal Logic / G. Formal Mereology / 1. Mereology
Megethology is the result of adding plural quantification to mereology
5. Theory of Logic / E. Structures of Logic / 6. Relations in Logic
We can use mereology to simulate quantification over relations
5. Theory of Logic / G. Quantification / 4. Substitutional Quantification
We can quantify over fictions by quantifying for real over their names
5. Theory of Logic / G. Quantification / 6. Plural Quantification
Plural quantification lacks a complete axiom system
Quantification sometimes commits to 'sets', but sometimes just to pluralities (or 'classes')
I like plural quantification, but am not convinced of its connection with second-order logic
5. Theory of Logic / G. Quantification / 7. Unorthodox Quantification
We could quantify over impossible objects - as bundles of properties
5. Theory of Logic / J. Model Theory in Logic / 2. Isomorphisms
A consistent theory just needs one model; isomorphic versions will do too, and large domains provide those
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Number / a. Axioms for numbers
Mathematics is generalisations about singleton functions
6. Mathematics / B. Foundations for Mathematics / 4. Definitions of Number / f. Zermelo numbers
Zermelo's model of arithmetic is distinctive because it rests on a primitive of set theory
6. Mathematics / B. Foundations for Mathematics / 5. Mathematics as Set Theory / a. Mathematics is set theory
Giving up classes means giving up successful mathematics because of dubious philosophy
6. Mathematics / B. Foundations for Mathematics / 6. Mathematical Structuralism / a. Structuralism
To be a structuralist, you quantify over relations
6. Mathematics / B. Foundations for Mathematics / 6. Mathematical Structuralism / e. Structuralism critique
We don't need 'abstract structures' to have structural truths about successor functions
7. Existence / A. Nature of Existence / 1. Nature of Existence
'Allists' embrace the existence of all controversial entities; 'noneists' reject all but the obvious ones
7. Existence / A. Nature of Existence / 2. Types of Existence
Lewis's distinction of 'existing' from 'being actual' is Meinong's between 'existing' and 'subsisting'
There are only two kinds: sets, and possibilia (actual and possible particulars)
We can't accept a use of 'existence' that says only some of the things there are actually exist
Existence doesn't come in degrees; once asserted, it can't then be qualified
7. Existence / A. Nature of Existence / 3. Being / a. Nature of Being
Every proposition is entirely about being
7. Existence / B. Change in Existence / 1. Nature of Change
You can't deny temporary intrinsic properties by saying the properties are relations (to times)
7. Existence / B. Change in Existence / 4. Events / a. Nature of events
The events that suit semantics may not be the events that suit causation
Events are classes, and so there is a mereology of their parts
Some events involve no change; they must, because causal histories involve unchanges
Events have inbuilt essences, as necessary conditions for their occurrence
7. Existence / B. Change in Existence / 4. Events / c. Reduction of events
An event is a property of a unique space-time region
7. Existence / C. Structure of Existence / 2. Reduction
Supervenience is reduction without existence denials, ontological priorities, or translatability
The whole truth supervenes on the physical truth
7. Existence / C. Structure of Existence / 5. Supervenience / a. Nature of supervenience
Supervenience concerns whether things could differ, so it is a modal notion
7. Existence / C. Structure of Existence / 5. Supervenience / b. Types of supervenience
Where pixels make up a picture, supervenience is reduction
7. Existence / C. Structure of Existence / 5. Supervenience / c. Significance of supervenience
A supervenience thesis is a denial of independent variation
7. Existence / C. Structure of Existence / 5. Supervenience / d. Humean supervenience
Humean supervenience says the world is just a vast mosaic of qualities in space-time
7. Existence / C. Structure of Existence / 8. Stuff / a. Pure stuff
Atomless gunk is an individual whose parts all have further proper parts
We have no idea of a third sort of thing, that isn't an individual, a class, or their mixture
7. Existence / D. Theories of Reality / 3. Anti-realism
Anti-realists see the world as imaginary, or lacking joints, or beyond reference, or beyond truth
7. Existence / D. Theories of Reality / 5. Physicalism
Materialism is (roughly) that two worlds cannot differ without differing physically
7. Existence / D. Theories of Reality / 6. Fictionalism
Abstractions may well be verbal fictions, in which we ignore some features of an object
7. Existence / D. Theories of Reality / 8. States of Affairs
How do things combine to make states of affairs? Constituents can repeat, and fail to combine
7. Existence / D. Theories of Reality / 9. Vagueness / c. Vagueness as semantic
Semantic vagueness involves alternative and equal precisifications of the language
Vagueness is semantic indecision: we haven't settled quite what our words are meant to express
Whether or not France is hexagonal depends on your standards of precision
Semantic indecision explains vagueness (if we have precisifications to be undecided about)
8. Modes of Existence / B. Properties / 1. Nature of Properties
Surely 'slept in by Washington' is a property of some bed?
Universals are wholly present in their instances, whereas properties are spread around
Properties don't have degree; they are determinate, and things have varying relations to them
The 'abundant' properties are just any bizarre property you fancy
8. Modes of Existence / B. Properties / 2. Need for Properties
To be a 'property' is to suit a theoretical role
8. Modes of Existence / B. Properties / 4. Intrinsic Properties
A disjunctive property can be unnatural, but intrinsic if its disjuncts are intrinsic
If a global intrinsic never varies between possible duplicates, all necessary properties are intrinsic
Global intrinsic may make necessarily coextensive properties both intrinsic or both extrinsic
If you think universals are immanent, you must believe them to be sparse, and not every related predicate
We must avoid circularity between what is intrinsic and what is natural
A property is 'intrinsic' iff it can never differ between duplicates
Ellipsoidal stars seem to have an intrinsic property which depends on other objects
All of the natural properties are included among the intrinsic properties
Being alone doesn't guarantee intrinsic properties; 'being alone' is itself extrinsic
Extrinsic properties come in degrees, with 'brother' less extrinsic than 'sibling'
8. Modes of Existence / B. Properties / 5. Natural Properties
For us, a property being natural is just an aspect of its featuring in the contents of our attitudes
All perfectly natural properties are intrinsic
We might try defining the natural properties by a short list of them
Natural properties fix resemblance and powers, and are picked out by universals
Natural properties give similarity, joint carving, intrinsicness, specificity, homogeneity...
Defining natural properties by means of laws of nature is potentially circular
We can't define natural properties by resemblance, if they are used to explain resemblance
I don't take 'natural' properties to be fixed by the nature of one possible world
Sparse properties rest either on universals, or on tropes, or on primitive naturalness
Natural properties figure in the analysis of similarity in intrinsic respects
Reference partly concerns thought and language, partly eligibility of referent by natural properties
Objects are demarcated by density and chemistry, and natural properties belong in what is well demarcated
Natural properties tend to belong to well-demarcated things, typically loci of causal chains
I assume there could be natural properties that are not instantiated in our world
8. Modes of Existence / B. Properties / 6. Categorical Properties
Lewis says properties are sets of actual and possible objects
Any class of things is a property, no matter how whimsical or irrelevant
The distinction between dispositional and 'categorical' properties leads to confusion
8. Modes of Existence / B. Properties / 10. Properties as Predicates
There are far more properties than any brain could ever encodify
We need properties as semantic values for linguistic expressions
There is the property of belonging to a set, so abundant properties are as numerous as the sets
Properties are very abundant (unlike universals), and are used for semantics and higher-order variables
8. Modes of Existence / B. Properties / 11. Properties as Sets
Properties are sets of their possible instances (which separates 'renate' from 'cordate')
The property of being F is identical with the set of objects, in all possible worlds, which are F
Accidentally coextensive properties come apart when we include their possible instances
Properties don't seem to be sets, because different properties can have the same set
If a property is relative, such as being a father or son, then set membership seems relative too
Trilateral and triangular seem to be coextensive sets in all possible worlds
I believe in properties, which are sets of possible individuals
A property is any class of possibilia
Properties are classes of possible and actual concrete particulars
A property is the set of its actual and possible instances
It would be easiest to take a property as the set of its instances
8. Modes of Existence / B. Properties / 13. Tropes / a. Nature of tropes
You must accept primitive similarity to like tropes, but tropes give a good account of it
Tropes are particular properties, which cannot recur, but can be exact duplicates
8. Modes of Existence / B. Properties / 13. Tropes / b. Critique of tropes
Tropes need a similarity primitive, so they cannot be used to explain similarity
Trope theory (unlike universals) needs a primitive notion of being duplicates
Trope theory needs a primitive notion for what unites some tropes
8. Modes of Existence / C. Powers and Dispositions / 2. Powers as Basic
If dispositions are more fundamental than causes, then they won't conceptually reduce to them
8. Modes of Existence / C. Powers and Dispositions / 3. Powers as Derived
Lewisian properties have powers because of their relationships to other properties
All dispositions must have causal bases
A disposition needs a causal basis, a property in a certain causal role. Could the disposition be the property?
8. Modes of Existence / C. Powers and Dispositions / 6. Dispositions / c. Dispositions as conditional
A 'finkish' disposition is real, but disappears when the stimulus occurs
8. Modes of Existence / C. Powers and Dispositions / 7. Against Powers
Most properties are causally irrelevant, and we can't spot the relevant ones.
8. Modes of Existence / D. Universals / 1. Universals
I suspend judgements about universals, but their work must done
Universals recur, are multiply located, wholly present, make things overlap, and are held in common
The main rivals to universals are resemblance or natural-class nominalism, or sparse trope theory
If particles were just made of universals, similar particles would be the same particle
8. Modes of Existence / D. Universals / 2. Need for Universals
Universals are meant to give an account of resemblance
8. Modes of Existence / D. Universals / 3. Instantiated Universals
Universals aren't parts of things, because that relationship is transitive, and universals need not be
8. Modes of Existence / E. Nominalism / 1. Nominalism / b. Nominalism about universals
The One over Many problem (in predication terms) deserves to be neglected (by ostriches)
8. Modes of Existence / E. Nominalism / 5. Class Nominalism
We can add a primitive natural/unnatural distinction to class nominalism
To have a property is to be a member of a class, usually a class of things
Class Nominalism and Resemblance Nominalism are pretty much the same
9. Objects / A. Existence of Objects / 4. Individuation / b. Individuation by properties
Total intrinsic properties give us what a thing is
9. Objects / B. Unity of Objects / 3. Unity Problems / b. Cat and its tail
If cats are vague, we deny that the many cats are one, or deny that the one cat is many
9. Objects / B. Unity of Objects / 3. Unity Problems / e. Vague objects
We have one cloud, but many possible boundaries and aggregates for it
9. Objects / C. Structure of Objects / 1. Structure of an Object
Structural universals have a necessary connection to the universals forming its parts
We can't get rid of structural universals if there are no simple universals
The 'pictorial' view of structural universals says they are wholes made of universals as parts
The structural universal 'methane' needs the universal 'hydrogen' four times over
Butane and Isobutane have the same atoms, but different structures
We could not uphold a truthmaker for 'Fa' without structures
The 'magical' view of structural universals says they are atoms, even though they have parts
If 'methane' is an atomic structural universal, it has nothing to connect it to its carbon universals
9. Objects / C. Structure of Objects / 5. Composition of an Object
Composition is not just making new things from old; there are too many counterexamples
The many are many and the one is one, so they can't be identical
Lewis affirms 'composition as identity' - that an object is no more than its parts
9. Objects / C. Structure of Objects / 8. Parts of Objects / b. Sums of parts
A gerrymandered mereological sum can be a mess, but still have natural joints
In mereology no two things consist of the same atoms
Trout-turkeys exist, despite lacking cohesion, natural joints and united causal power
Given cats, a fusion of cats adds nothing further to reality
The one has different truths from the many; it is one rather than many, one rather than six
9. Objects / C. Structure of Objects / 8. Parts of Objects / c. Wholes from parts
Mereological composition is unrestricted: any class of things has a mereological sum
There are no restrictions on composition, because they would be vague, and composition can't be vague
Lewis prefers giving up singletons to giving up sums
A whole is distinct from its parts, but is not a further addition in ontology
Different things (a toy house and toy car) can be made of the same parts at different times
Lewis only uses fusions to create unities, but fusions notoriously flatten our distinctions
A commitment to cat-fusions is not a further commitment; it is them and they are it
I say that absolutely any things can have a mereological fusion
9. Objects / D. Essence of Objects / 1. Essences of Objects
Aristotelian essentialism says essences are not relative to specification
9. Objects / D. Essence of Objects / 7. Essence and Necessity / a. Essence as necessary properties
An essential property is one possessed by all counterparts
9. Objects / E. Objects over Time / 1. Objects over Time
A thing 'perdures' if it has separate temporal parts, and 'endures' if it is wholly present at different times
9. Objects / E. Objects over Time / 2. Objects that Change
Properties cannot be relations to times, if there are temporary properties which are intrinsic
9. Objects / E. Objects over Time / 3. Three-Dimensionalism
Endurance is the wrong account, because things change intrinsic properties like shape
There are three responses to the problem that intrinsic shapes do not endure
9. Objects / E. Objects over Time / 12. Origin as Essential
I can ask questions which create a context in which origin ceases to be essential
9. Objects / F. Identity among Objects / 5. Self-Identity
Identity is simple - absolutely everything is self-identical, and nothing is identical to another thing
9. Objects / F. Identity among Objects / 6. Identity between Objects
Two things can never be identical, so there is no problem
10. Modality / A. Necessity / 4. De re / De dicto modality
De re modal predicates are ambiguous
10. Modality / A. Necessity / 7. Natural Necessity
Causal necessities hold in all worlds compatible with the laws of nature
10. Modality / B. Possibility / 7. Chance
We can explain a chance event, but can never show why some other outcome did not occur
10. Modality / B. Possibility / 8. Conditionals / a. Conditionals
A conditional probability does not measure the probability of the truth of any proposition
10. Modality / B. Possibility / 8. Conditionals / c. Truth-function conditionals
Lewis says indicative conditionals are truth-functional
10. Modality / B. Possibility / 9. Counterfactuals
Backtracking counterfactuals go from supposed events to their required causal antecedents
In good counterfactuals the consequent holds in world like ours except that the antecedent is true
For true counterfactuals, both antecedent and consequent true is closest to actuality
10. Modality / D. Knowledge of Modality / 4. Conceivable as Possible / b. Conceivable but impossible
The impossible can be imagined as long as it is a bit vague
10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds
There are no free-floating possibilia; they have mates in a world, giving them extrinsic properties
10. Modality / E. Possible worlds / 1. Possible Worlds / b. Impossible worlds
Possible worlds can contain contradictions if such worlds are seen as fictions
On mountains or in worlds, reporting contradictions is contradictory, so no such truths can be reported
10. Modality / E. Possible worlds / 1. Possible Worlds / c. Possible worlds realism
For Lewis there is no real possibility, since all possibilities are actual
Lewis posits possible worlds just as Quine says that physics needs numbers and sets
For me, all worlds are equal, with each being actual relative to itself
If possible worlds really exist, then they are part of actuality
A world is a maximal mereological sum of spatiotemporally interrelated things
10. Modality / E. Possible worlds / 1. Possible Worlds / d. Possible worlds actualism
Lewis can't know possible worlds without first knowing what is possible or impossible
What are the ontological grounds for grouping possibilia into worlds?
The actual world is just the world you are in
Lewis rejects actualism because he identifies properties with sets
Ersatzers say we have one world, and abstract representations of how it might have been
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / a. Nature of possible worlds
Ersatz worlds represent either through language, or by models, or magically
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / b. Worlds as fictions
Linguistic possible worlds need a complete supply of unique names for each thing
Maximal consistency for a world seems a modal distinction, concerning what could be true together
Linguistic possible worlds have problems of inconsistencies, no indiscernibles, and vocabulary
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / c. Worlds as propositions
If sets exist, then defining worlds as proposition sets implies an odd distinction between existing and actual
10. Modality / E. Possible worlds / 3. Transworld Objects / b. Rigid designation
It doesn't take the whole of a possible Humphrey to win the election
A logically determinate name names the same thing in every possible world
10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts
Essential attributes are those shared with all the counterparts
The counterpart relation is sortal-relative, so objects need not be a certain way
Why should statements about what my 'counterpart' could have done interest me?
Counterpart theory is bizarre, as no one cares what happens to a mere counterpart
Counterparts are not the original thing, but resemble it more than other things do
If the closest resembler to you is in fact quite unlike you, then you have no counterpart
A counterpart in a possible world is sufficiently similar, and more similar than anything else
In counterpart theory 'Humphrey' doesn't name one being, but a mereological sum of many beings
10. Modality / E. Possible worlds / 3. Transworld Objects / d. Haecceitism
Extreme haecceitists could say I might have been a poached egg, but it is too remote to consider
Haecceitism implies de re differences but qualitative identity
Extreme haecceitism says you might possibly be a poached egg
11. Knowledge Aims / A. Knowledge / 4. Belief / a. Beliefs
A content is a property, and believing it is self-ascribing that property
The timid student has knowledge without belief, lacking confidence in their correct answer
11. Knowledge Aims / B. Certain Knowledge / 4. Fallibilism
To say S knows P, but cannot eliminate not-P, sounds like a contradiction
12. Knowledge Sources / B. Perception / 2. Qualities in Perception / a. Qualities in perception
Some say qualities are parts of things - as repeatable universals, or as particulars
13. Knowledge Criteria / A. Justification Problems / 1. Justification / b. Need for justification
Justification is neither sufficient nor necessary for knowledge
13. Knowledge Criteria / C. External Justification / 2. Causal Justification
General causal theories of knowledge are refuted by mathematics
13. Knowledge Criteria / C. External Justification / 6. Contextual Justification / a. Contextualism
Knowing is context-sensitive because the domain of quantification varies
We have knowledge if alternatives are eliminated, but appropriate alternatives depend on context
14. Science / B. Scientific Theories / 8. Ramsey Sentences
A Ramsey sentence just asserts that a theory can be realised, without saying by what
The Ramsey sentence of a theory says that it has at least one realisation
It is better to have one realisation of a theory than many - but it may not always be possible
There is a method for defining new scientific terms just using the terms we already understand
14. Science / C. Induction / 2. Aims of Induction
Induction is just reasonable methods of inferring the unobserved from the observed
14. Science / C. Induction / 5. Paradoxes of Induction / a. Grue problem
To just expect unexamined emeralds to be grue would be totally unreasonable
14. Science / D. Explanation / 1. Explanation / b. Aims of explanation
Does a good explanation produce understanding? That claim is just empty
14. Science / D. Explanation / 2. Types of Explanation / d. Lawlike explanations
Science may well pursue generalised explanation, rather than laws
14. Science / D. Explanation / 2. Types of Explanation / e. Necessity in explanations
A good explanation is supposed to show that the event had to happen
14. Science / D. Explanation / 2. Types of Explanation / f. Causal explanations
An explanation tells us how an event was caused
Lewis endorses the thesis that all explanation of singular events is causal explanation
Often explanaton seeks fundamental laws, rather than causal histories
To explain an event is to provide some information about its causal history
14. Science / D. Explanation / 2. Types of Explanation / k. Probabilistic explanations
If the well-ordering of a pack of cards was by shuffling, the explanation would make it more surprising
15. Nature of Minds / A. Nature of Mind / 1. Mind / b. Purpose of mind
A mind is an organ of representation
15. Nature of Minds / B. Features of Minds / 5. Qualia / a. Nature of qualia
Part of the folk concept of qualia is what makes recognition and comparison possible
15. Nature of Minds / C. Capacities of Minds / 3. Abstraction by mind
Maybe abstraction is just mereological subtraction
16. Persons / F. Free Will / 2. Free Will Theories / b. Determinism
Determinism says there can't be two identical worlds up to a time, with identical laws, which then differ
17. Mind and Body / C. Functionalism / 4. Causal Functionalism
Experiences are defined by their causal role, and causal roles belong to physical states
'Pain' contingently names the state that occupies the causal role of pain
Type-type psychophysical identity is combined with a functional characterisation of pain
17. Mind and Body / E. Mind as Physical / 1. Physical Mind
Human pain might be one thing; Martian pain might be something else
The application of 'pain' to physical states is non-rigid and contingent
Psychophysical identity implies the possibility of idealism or panpsychism
17. Mind and Body / E. Mind as Physical / 2. Reduction of Mind
I am a reductionist about mind because I am an a priori reductionist about everything
17. Mind and Body / E. Mind as Physical / 7. Anti-Physicalism / b. Multiple realisability
A theory must be mixed, to cover qualia without behaviour, and behaviour without qualia
18. Thought / A. Modes of Thought / 2. Propositional Attitudes
Attitudes involve properties (not propositions), and belief is self-ascribing the properties
18. Thought / A. Modes of Thought / 5. Folk Psychology
Folk psychology makes good predictions, by associating mental states with causal roles
18. Thought / A. Modes of Thought / 9. Indexical Thought
Lewis's popular centred worlds approach gives an attitude an index of world, subject and time
18. Thought / B. Mechanics of Thought / 4. Language of Thought
Folk psychology doesn't say that there is a language of thought
18. Thought / C. Content / 6. Broad Content
Nothing shows that all content is 'wide', or that wide content has logical priority
If you don't share an external world with a brain-in-a-vat, then externalism says you don't share any beliefs.
A spontaneous duplicate of you would have your brain states but no experience, so externalism would deny him any beliefs
Wide content derives from narrow content and relationships with external things
18. Thought / E. Abstraction / 1. Abstract Thought
Abstraction is usually explained either by example, or conflation, or abstraction, or negatively
18. Thought / E. Abstraction / 3. Abstracta by Ignoring
The Way of Abstraction says an incomplete description of a concrete entity is the complete abstraction
18. Thought / E. Abstraction / 4. Abstracta by Example
The Way of Example compares donkeys and numbers, but what is the difference, and what are numbers?
18. Thought / E. Abstraction / 6. Abstracta by Conflation
If abstractions are non-spatial, then both sets and universals seem to have locations
Abstracta can be causal: sets can be causes or effects; there can be universal effects; events may be sets
If we can abstract the extrinsic relations and features of objects, abstraction isn't universals or tropes
If universals or tropes are parts of things, then abstraction picks out those parts
18. Thought / E. Abstraction / 7. Abstracta by Equivalence
For most sets, the concept of equivalence is too artificial to explain abstraction
The abstract direction of a line is the equivalence class of it and all lines parallel to it
Mathematicians abstract by equivalence classes, but that doesn't turn a many into one
18. Thought / E. Abstraction / 8. Abstractionism Critique
We can't account for an abstraction as 'from' something if the something doesn't exist
19. Language / A. Nature of Meaning / 4. Meaning as Truth-Conditions
A theory of perspectival de se content gives truth conditions relative to an agent
19. Language / A. Nature of Meaning / 7. Meaning Holism / c. Meaning by Role
A particular functional role is what gives content to a thought
19. Language / C. Reference / 3. Direct Reference / b. Causal reference
Causal theories of reference make errors in reference easy
19. Language / C. Reference / 4. Descriptive Reference / b. Reference by description
Descriptive theories remain part of the theory of reference (with seven mild modifications)
19. Language / D. Propositions / 2. Abstract Propositions / b. Propositions as possible worlds
A proposition is a set of entire possible worlds which instantiate a particular property
A proposition is the property of being a possible world where it holds true
Propositions can't have syntactic structure if they are just sets of worlds
A proposition is a set of possible worlds where it is true
19. Language / F. Communication / 6. Interpreting Language / c. Principle of charity
A sophisticated principle of charity sometimes imputes error as well as truth
We need natural properties in order to motivate the principle of charity
Basic to pragmatics is taking a message in a way that makes sense of it
26. Natural Theory / B. Concepts of Nature / 1. Basis of Nature
Physics aim for a list of natural properties
26. Natural Theory / B. Concepts of Nature / 4. Time / h. Growing block of time
It is quite implausible that the future is unreal, as that would terminate everything
26. Natural Theory / C. Causation / 1. Causation / a. Causation
Causation is a general relation derived from instances of causal dependence
26. Natural Theory / C. Causation / 1. Causation / b. Types of cause
Explaining match lighting in general is like explaining one lighting of a match
26. Natural Theory / C. Causation / 1. Causation / e. Direction of causation
A theory of causation should explain why cause precedes effect, not take it for granted
I reject making the direction of causation axiomatic, since that takes too much for granted
There are few traces of an event before it happens, but many afterwards
26. Natural Theory / C. Causation / 2. Particular Causation / d. Selecting the cause
Ways of carving causes may be natural, but never 'right'
It is just individious discrimination to pick out one cause and label it as 'the' cause
The modern regularity view says a cause is a member of a minimal set of sufficient conditions
We only pick 'the' cause for the purposes of some particular enquiry.
26. Natural Theory / C. Causation / 3. General Causation / a. Constant conjunction
Regularity analyses could make c an effect of e, or an epiphenomenon, or inefficacious, or pre-empted
26. Natural Theory / C. Causation / 3. General Causation / c. Counterfactual causation
Lewis has basic causation, counterfactuals, and a general ancestral (thus handling pre-emption)
The counterfactual view says causes are necessary (rather than sufficient) for their effects
Counterfactual causation implies all laws are causal, which they aren't
One event causes another iff there is a causal chain from first to second
My counterfactual analysis applies to particular cases, not generalisations
Counterfactuals 'backtrack' if a different present implies a different past
Causal counterfactuals must avoid backtracking, to avoid epiphenomena and preemption
Causation is when at the closest world without the cause, there is no effect either
Causal dependence is counterfactual dependence between events
26. Natural Theory / D. Laws of Nature / 1. Laws of Nature
Physics discovers laws and causal explanations, and also the natural properties required
26. Natural Theory / D. Laws of Nature / 4. Regularities / b. Best system theory
Laws are the best axiomatization of the total history of world events or facts
A number of systematizations might tie as the best and most coherent system
If simplicity and strength are criteria for laws of nature, that introduces a subjective element
A law of nature is a general axiom of the deductive system that is best for simplicity and strength
Lewis later proposed the axioms at the intersection of the best theories (which may be few)
A law of nature is any regularity that earns inclusion in the ideal system
26. Natural Theory / D. Laws of Nature / 9. Counterfactual Claims
An event causes another just if the second event would not have happened without the first
Lewis's account of counterfactuals is fine if we know what a law of nature is, but it won't explain the latter
26. Natural Theory / D. Laws of Nature / 12. Against Laws of Nature
The world is just a vast mosaic of little matters of local particular fact