Ideas of Theodore Sider, by Theme

[American, fl. 2001, Professor at Rutgers University, New Jersey, then New York University.]

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1. Philosophy / D. Nature of Philosophy / 3. Philosophy Defined
9218 Maybe what distinguishes philosophy from science is its pursuit of necessary truths
1. Philosophy / E. Nature of Metaphysics / 2. Possibility of Metaphysics
14721 Metaphysical enquiry can survive if its conclusions are tentative
15010 Your metaphysics is 'cheating' if your ontology won't support the beliefs you accept
1. Philosophy / E. Nature of Metaphysics / 4. Metaphysics as Science
14977 Metaphysics is not about what exists or is true or essential; it is about the structure of reality
14994 Extreme doubts about metaphysics also threaten to undermine the science of unobservables
1. Philosophy / E. Nature of Metaphysics / 6. Metaphysics as Conceptual
15003 It seems unlikely that the way we speak will give insights into the universe
1. Philosophy / F. Analytic Philosophy / 4. Conceptual Analysis
14986 Conceptual analysts trust particular intuitions much more than general ones
2. Reason / D. Definition / 13. Against Definition
15015 It seems possible for a correct definition to be factually incorrect, as in defining 'contact'
14981 Philosophical concepts are rarely defined, and are not understood by means of definitions
3. Truth / A. Truth Problems / 3. Value of Truth
14992 We don't care about plain truth, but truth in joint-carving terms
3. Truth / B. Truthmakers / 5. What Makes Truths / b. Objects make truths
15012 Orthodox truthmaker theories make entities fundamental, but that is poor for explanation
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / b. Terminology of PL
13689 'Theorems' are formulas provable from no premises at all
4. Formal Logic / B. Propositional Logic PL / 3. Truth Tables
13705 Truth tables assume truth functionality, and are just pictures of truth functions
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / c. System D
13710 In D we add that 'what is necessary is possible'; then tautologies are possible, and contradictions not necessary
13706 Intuitively, deontic accessibility seems not to be reflexive, but to be serial
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / f. System B
13711 System B introduces iterated modalities
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / h. System S5
13708 S5 is the strongest system, since it has the most valid formulas, because it is easy to be S5-valid
4. Formal Logic / D. Modal Logic ML / 5. Epistemic Logic
13712 Epistemic accessibility is reflexive, and allows positive and negative introspection (KK and K¬K)
4. Formal Logic / D. Modal Logic ML / 6. Temporal Logic
13714 We can treat modal worlds as different times
4. Formal Logic / D. Modal Logic ML / 7. Barcan Formula
13723 System B is needed to prove the Barcan Formula
13718 The Barcan Formula ∀x□Fx→□∀xFx may be a defect in modal logic
13720 Converse Barcan Formula: □∀αφ→∀α□φ
15023 The Barcan schema implies if X might have fathered something, there is something X might have fathered
4. Formal Logic / E. Nonclassical Logics / 2. Intuitionist Logic
13715 You can employ intuitionist logic without intuitionism about mathematics
4. Formal Logic / G. Formal Mereology / 1. Mereology
15004 'Gunk' is an object in which proper parts all endlessly have further proper parts
4. Formal Logic / G. Formal Mereology / 3. Axioms of Mereology
14984 Which should be primitive in mereology - part, or overlap?
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
14980 There is a real issue over what is the 'correct' logic
15000 'It is raining' and 'it is not raining' can't be legislated, so we can't legislate 'p or ¬p'
5. Theory of Logic / A. Overview of Logic / 6. Classical Logic
15020 Classical logic is good for mathematics and science, but less good for natural language
5. Theory of Logic / B. Logical Consequence / 1. Logical Consequence
13682 Maybe logical consequence is impossibility of the premises being true and the consequent false
13679 Maybe logical consequence is more a matter of provability than of truth-preservation
13678 The most popular account of logical consequence is the semantic or model-theoretic one
13680 Maybe logical consequence is a primitive notion
15029 Modal accounts of logical consequence are simple necessity, or essential use of logical words
5. Theory of Logic / B. Logical Consequence / 3. Deductive Consequence |-
13722 A 'theorem' is an axiom, or the last line of a legitimate proof
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
15019 Define logical constants by role in proofs, or as fixed in meaning, or as topic-neutral
5. Theory of Logic / E. Structures of Logic / 4. Variables in Logic
13696 When a variable is 'free' of the quantifier, the result seems incapable of truth or falsity
5. Theory of Logic / E. Structures of Logic / 5. Functions in Logic
13700 A 'total' function must always produce an output for a given domain
5. Theory of Logic / F. Referring in Logic / 3. Property (λ-) Abstraction
13703 λ can treat 'is cold and hungry' as a single predicate
5. Theory of Logic / H. Proof Systems / 2. Axiomatic Proof
13687 No assumptions in axiomatic proofs, so no conditional proof or reductio
13688 Good axioms should be indisputable logical truths
5. Theory of Logic / H. Proof Systems / 3. Proof from Assumptions
13690 Proof by induction 'on the length of the formula' deconstructs a formula into its accepted atoms
13691 Induction has a 'base case', then an 'inductive hypothesis', and then the 'inductive step'
5. Theory of Logic / H. Proof Systems / 4. Natural Deduction
13685 Natural deduction helpfully allows reasoning with assumptions
15001 'Tonk' is supposed to follow the elimination and introduction rules, but it can't be so interpreted
5. Theory of Logic / H. Proof Systems / 6. Sequent Calculi
13686 We can build proofs just from conclusions, rather than from plain formulae
5. Theory of Logic / I. Semantics of Logic / 1. Semantics of Logic
13697 Valuations in PC assign truth values to formulas relative to variable assignments
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
13684 The semantical notion of a logical truth is validity, being true in all interpretations
13704 It is hard to say which are the logical truths in modal logic, especially for iterated modal operators
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
13724 In model theory, first define truth, then validity as truth in all models, and consequence as truth-preservation
5. Theory of Logic / K. Features of Logics / 4. Completeness
13698 In a complete logic you can avoid axiomatic proofs, by using models to show consequences
5. Theory of Logic / K. Features of Logics / 6. Compactness
13699 Compactness surprisingly says that no contradictions can emerge when the set goes infinite
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / e. Peano arithmetic 2nd-order
13701 A single second-order sentence validates all of arithmetic - but this can't be proved axiomatically
7. Existence / B. Change in Existence / 2. Processes
14760 Four-dimensionalism sees things and processes as belonging in the same category
7. Existence / C. Structure of Existence / 5. Supervenience / a. Nature of supervenience
15017 Supervenience is a modal connection
7. Existence / C. Structure of Existence / 6. Fundamentals / b. Types of fundamental
15008 Is fundamentality in whole propositions (and holistic), or in concepts (and atomic)?
15013 Tables and chairs have fundamental existence, but not fundamental natures
7. Existence / C. Structure of Existence / 8. Stuff / a. Pure stuff
15014 Unlike things, stuff obeys unrestricted composition and mereological essentialism
7. Existence / D. Theories of Reality / 8. States of Affairs
15009 We must distinguish 'concrete' from 'abstract' and necessary states of affairs.
7. Existence / D. Theories of Reality / 9. Vagueness / f. Supervaluation for vagueness
13692 A 'precisification' of a trivalent interpretation reduces it to a bivalent interpretation
13693 A 'supervaluation' assigns further Ts and Fs, if they have been assigned in every precisification
13694 We can 'sharpen' vague terms, and then define truth as true-on-all-sharpenings
13695 Supervaluational logic is classical, except when it adds the 'Definitely' operator
7. Existence / D. Theories of Reality / 10. Ontological Commitment / d. Commitment of theories
14983 Accept the ontology of your best theory - and also that it carves nature at the joints
8. Modes of Existence / A. Relations / 1. Nature of Relations
13683 A relation is a feature of multiple objects taken together
8. Modes of Existence / B. Properties / 3. Types of Properties
14978 A property is intrinsic if an object alone in the world can instantiate it
8. Modes of Existence / B. Properties / 6. Categorical Properties
14194 Proper ontology should only use categorical (actual) properties, not hypothetical ones
8. Modes of Existence / B. Properties / 10. Properties as Predicates
14995 Predicates can be 'sparse' if there is a universal, or if there is a natural property or relation
9. Objects / A. Existence of Objects / 5. Individuation / e. Individuation by kind
14745 If sortal terms fix the kind and the persistence conditions, we need to know what kinds there are
9. Objects / B. Unity of Objects / 3. Unity Problems / b. Cat and its tail
14740 If Tib is all of Tibbles bar her tail, when Tibbles loses her tail, two different things become one
9. Objects / B. Unity of Objects / 3. Unity Problems / c. Statue and clay
14752 Artists 'create' statues because they are essentially statues, and so lack identity with the lump of clay
9. Objects / B. Unity of Objects / 3. Unity Problems / d. Coincident objects
14743 The stage view of objects is best for dealing with coincident entities
9. Objects / C. Structure of Objects / 5. Composition of an Object
14747 'Composition as identity' says that an object just is the objects which compose it
9. Objects / D. Essence of Objects / 12. Essential Parts
14757 Mereological essentialism says an object's parts are necessary for its existence
9. Objects / D. Essence of Objects / 15. Against Essentialism
15026 Essence (even if nonmodal) is not fundamental in metaphysics
9. Objects / E. Objects over Time / 3. Three-Dimensionalism
14727 Three-dimensionalists assert 'enduring', being wholly present at each moment, and deny 'temporal parts'
14738 Some might say that its inconsistency with time travel is a reason to favour three-dimensionalism
9. Objects / E. Objects over Time / 4. Four-Dimensionalism
14729 4D says each spatiotemporal object must have a temporal part at every moment at which it exists
14726 Four-dimensionalists assert 'temporal parts', 'perduring', and being spread out over time
14728 4D says intrinsic change is difference between successive parts
9. Objects / E. Objects over Time / 5. Temporal Parts
14731 Temporal parts are instantaneous
14730 Temporal parts exist, but are not prior building blocks for objects
14758 How can an instantaneous stage believe anything, if beliefs take time?
14762 Four-dimensionalism says temporal parts are caused (through laws of motion) by previous temporal parts
9. Objects / E. Objects over Time / 9. Ship of Theseus
14741 The ship undergoes 'asymmetric' fission, where one candidate is seen as stronger
9. Objects / F. Identity among Objects / 7. Indiscernible Objects
13702 The identity of indiscernibles is necessarily true, if being a member of some set counts as a property
9. Objects / F. Identity among Objects / 8. Leibniz's Law
14754 If you say Leibniz's Law doesn't apply to 'timebound' properties, you are no longer discussing identity
10. Modality / A. Necessity / 3. Types of Necessity
13721 'Strong' necessity in all possible worlds; 'weak' necessity in the worlds where the relevant objects exist
10. Modality / A. Necessity / 5. Metaphysical Necessity
13707 Maybe metaphysical accessibility is intransitive, if a world in which I am a frog is impossible
10. Modality / A. Necessity / 6. Logical Necessity
13709 Logical truths must be necessary if anything is
10. Modality / B. Possibility / 8. Conditionals / b. Types of conditional
13716 'If B hadn't shot L someone else would have' if false; 'If B didn't shoot L, someone else did' is true
10. Modality / C. Sources of Modality / 1. Sources of Necessity
15030 Humeans say that we decide what is necessary
15031 Modal terms in English are entirely contextual, with no modality outside the language
10. Modality / C. Sources of Modality / 3. Necessity by Convention
15028 Conventionalism doesn't seem to apply to examples of the necessary a posteriori
15027 If truths are necessary 'by convention', that seems to make them contingent
10. Modality / C. Sources of Modality / 4. Necessity from Concepts
15033 Humeans says mathematics and logic are necessary because that is how our concept of necessity works
10. Modality / C. Sources of Modality / 5. Modality from Actuality
15025 The world does not contain necessity and possibility - merely how things are
10. Modality / E. Possible worlds / 3. Transworld Objects / a. Transworld identity
13717 Transworld identity is not a problem in de dicto sentences, which needn't identify an individual
10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts
14763 Counterparts rest on similarity, so there are many such relations in different contexts
10. Modality / E. Possible worlds / 3. Transworld Objects / e. Possible Objects
13719 Barcan Formula problem: there might have been a ghost, despite nothing existing which could be a ghost
14. Science / B. Scientific Theories / 2. Aim of Science
14988 A theory which doesn't fit nature is unexplanatory, even if it is true
14. Science / B. Scientific Theories / 8. Ramsey Sentences
14982 If I used ramsey sentences to eliminate fundamentality from my theory, that would be a real loss
14. Science / C. Induction / 5. Paradoxes of Induction / a. Grue problem
14989 Problem predicates in induction don't reflect the structure of nature
14997 Two applications of 'grue' do not guarantee a similarity between two things
14. Science / C. Induction / 6. Bayes's Theorem
14990 Bayes produces weird results if the prior probabilities are bizarre
14. Science / D. Explanation / 1. Explanation / a. Explanation
15005 Explanations must cite generalisations
14. Science / D. Explanation / 3. Best Explanation / b. Ultimate explanation
15011 If the ultimate explanation is a list of entities, no laws, patterns or mechanisms can be cited
15. Nature of Minds / B. Features of Minds / 4. Intentionality / a. Nature of intentionality
15018 Intentionality is too superficial to appear in the catalogue of ultimate physics
19. Language / A. Nature of Meaning / 6. Meaning as Use
14999 Prior to conventions, not all green things were green?
19. Language / E. Analyticity / 2. Analytic Truths
14998 Conventions are contingent and analytic truths are necessary, so that isn't their explanation
19. Language / E. Analyticity / 4. Analytic/Synthetic Critique
15016 Analyticity has lost its traditional role, which relied on truth by convention
26. Natural Theory / D. Laws of Nature / 11. Against Laws of Nature
14987 Many of the key theories of modern physics do not appear to be 'laws'
14985 The notion of law doesn't seem to enhance physical theories
27. Natural Reality / A. Classical Physics / 1. Mechanics / a. Explaining movement
14725 Maybe motion is a dynamical quantity intrinsic to a thing at a particular time
27. Natural Reality / C. Space / 4. Substantival Space
14991 Space has real betweenness and congruence structure (though it is not the Euclidean concepts)
27. Natural Reality / C. Space / 6. Space-Time
14735 Space is 3D and lacks a direction; time seems connected to causation
15021 The central question in the philosophy of time is: How alike are time and space?
27. Natural Reality / D. Time / 1. Nature of Time / f. Eternalism
15024 The spotlight theorists accepts eternal time, but with a spotlight of the present moving across it
27. Natural Reality / D. Time / 1. Nature of Time / g. Growing block
14722 Between presentism and eternalism is the 'growing block' view - the past is real, the future is not
27. Natural Reality / D. Time / 1. Nature of Time / h. Presentism
14724 Presentists must deny truths about multiple times
14756 For Presentists there must always be a temporal vantage point for any description
27. Natural Reality / D. Time / 2. Passage of Time / c. Tenses and time
14723 Talk using tenses can be eliminated, by reducing it to indexical connections for an utterance
27. Natural Reality / D. Time / 2. Passage of Time / f. Tenseless (B) series
14734 The B-series involves eternalism, and the reduction of tense
14736 The B-theory is adequate, except that it omits to say which time is present