119 ideas
11051 | Frege's logical approach dominates the analytical tradition [Hanna] |
11054 | Scientism says most knowledge comes from the exact sciences [Hanna] |
10237 | Coherence is a primitive, intuitive notion, not reduced to something formal [Shapiro] |
10204 | An 'implicit definition' gives a direct description of the relations of an entity [Shapiro] |
11070 | 'Denying the antecedent' fallacy: φ→ψ, ¬φ, so ¬ψ [Hanna] |
11071 | 'Affirming the consequent' fallacy: φ→ψ, ψ, so φ [Hanna] |
11088 | We can list at least fourteen informal fallacies [Hanna] |
11059 | Circular arguments are formally valid, though informally inadmissible [Hanna] |
11089 | Formally, composition and division fallacies occur in mereology [Hanna] |
10206 | Modal operators are usually treated as quantifiers [Shapiro] |
14684 | A world is 'accessible' to another iff the first is possible according to the second [Salmon,N] |
14669 | For metaphysics, T may be the only correct system of modal logic [Salmon,N] |
14692 | System B implies that possibly-being-realized is an essential property of the world [Salmon,N] |
14667 | System B has not been justified as fallacy-free for reasoning on what might have been [Salmon,N] |
14668 | In B it seems logically possible to have both p true and p is necessarily possibly false [Salmon,N] |
14671 | What is necessary is not always necessarily necessary, so S4 is fallacious [Salmon,N] |
14686 | S5 modal logic ignores accessibility altogether [Salmon,N] |
14691 | S5 believers say that-things-might-have-been-that-way is essential to ways things might have been [Salmon,N] |
14693 | The unsatisfactory counterpart-theory allows the retention of S5 [Salmon,N] |
14670 | Metaphysical (alethic) modal logic concerns simple necessity and possibility (not physical, epistemic..) [Salmon,N] |
10252 | The Axiom of Choice seems to license an infinite amount of choosing [Shapiro] |
10208 | Axiom of Choice: some function has a value for every set in a given set [Shapiro] |
10207 | Anti-realists reject set theory [Shapiro] |
11058 | Logic is explanatorily and ontologically dependent on rational animals [Hanna] |
11072 | Logic is personal and variable, but it has a universal core [Hanna] |
11061 | Intensional consequence is based on the content of the concepts [Hanna] |
10259 | The two standard explanations of consequence are semantic (in models) and deductive [Shapiro] |
10257 | Intuitionism only sanctions modus ponens if all three components are proved [Shapiro] |
10253 | Either logic determines objects, or objects determine logic, or they are separate [Shapiro] |
10251 | The law of excluded middle might be seen as a principle of omniscience [Shapiro] |
10212 | Classical connectives differ from their ordinary language counterparts; '∧' is timeless, unlike 'and' [Shapiro] |
10209 | A function is just an arbitrary correspondence between collections [Shapiro] |
10268 | Maybe plural quantifiers should be understood in terms of classes or sets [Shapiro] |
10235 | A sentence is 'satisfiable' if it has a model [Shapiro] |
10239 | The central notion of model theory is the relation of 'satisfaction' [Shapiro] |
10240 | Model theory deals with relations, reference and extensions [Shapiro] |
10238 | The set-theoretical hierarchy contains as many isomorphism types as possible [Shapiro] |
10214 | Theory ontology is never complete, but is only determined 'up to isomorphism' [Shapiro] |
10234 | Any theory with an infinite model has a model of every infinite cardinality [Shapiro] |
10201 | Virtually all of mathematics can be modeled in set theory [Shapiro] |
10213 | Real numbers are thought of as either Cauchy sequences or Dedekind cuts [Shapiro] |
18243 | Understanding the real-number structure is knowing usage of the axiomatic language of analysis [Shapiro] |
18245 | Cuts are made by the smallest upper or largest lower number, some of them not rational [Shapiro] |
10236 | There is no grounding for mathematics that is more secure than mathematics [Shapiro] |
10256 | For intuitionists, proof is inherently informal [Shapiro] |
10202 | Natural numbers just need an initial object, successors, and an induction principle [Shapiro] |
10205 | Mathematics originally concerned the continuous (geometry) and the discrete (arithmetic) [Shapiro] |
10222 | Mathematical foundations may not be sets; categories are a popular rival [Shapiro] |
10218 | Baseball positions and chess pieces depend entirely on context [Shapiro] |
10224 | The even numbers have the natural-number structure, with 6 playing the role of 3 [Shapiro] |
10228 | Could infinite structures be apprehended by pattern recognition? [Shapiro] |
10230 | The 4-pattern is the structure common to all collections of four objects [Shapiro] |
10249 | The main mathematical structures are algebraic, ordered, and topological [Shapiro] |
10273 | Some structures are exemplified by both abstract and concrete [Shapiro] |
10276 | Mathematical structures are defined by axioms, or in set theory [Shapiro] |
10270 | The main versions of structuralism are all definitionally equivalent [Shapiro] |
10221 | Is there is no more to structures than the systems that exemplify them? [Shapiro] |
10248 | Number statements are generalizations about number sequences, and are bound variables [Shapiro] |
10220 | Because one structure exemplifies several systems, a structure is a one-over-many [Shapiro] |
10223 | There is no 'structure of all structures', just as there is no set of all sets [Shapiro] |
8703 | Shapiro's structuralism says model theory (comparing structures) is the essence of mathematics [Shapiro, by Friend] |
10274 | Does someone using small numbers really need to know the infinite structure of arithmetic? [Shapiro] |
10200 | We distinguish realism 'in ontology' (for objects), and 'in truth-value' (for being either true or false) [Shapiro] |
10210 | If mathematical objects are accepted, then a number of standard principles will follow [Shapiro] |
10215 | Platonists claim we can state the essence of a number without reference to the others [Shapiro] |
10233 | Platonism must accept that the Peano Axioms could all be false [Shapiro] |
10244 | Intuition is an outright hindrance to five-dimensional geometry [Shapiro] |
10280 | A stone is a position in some pattern, and can be viewed as an object, or as a location [Shapiro] |
11063 | Logicism struggles because there is no decent theory of analyticity [Hanna] |
10254 | Can the ideal constructor also destroy objects? [Shapiro] |
10255 | Presumably nothing can block a possible dynamic operation? [Shapiro] |
10279 | Can we discover whether a deck is fifty-two cards, or a person is time-slices or molecules? [Shapiro] |
11055 | Supervenience can add covariation, upward dependence, and nomological connection [Hanna] |
10227 | The abstract/concrete boundary now seems blurred, and would need a defence [Shapiro] |
10226 | Mathematicians regard arithmetic as concrete, and group theory as abstract [Shapiro] |
10262 | Fictionalism eschews the abstract, but it still needs the possible (without model theory) [Shapiro] |
10277 | Structuralism blurs the distinction between mathematical and ordinary objects [Shapiro] |
10272 | The notion of 'object' is at least partially structural and mathematical [Shapiro] |
10275 | A blurry border is still a border [Shapiro] |
14678 | Any property is attached to anything in some possible world, so I am a radical anti-essentialist [Salmon,N] |
11083 | A sentence is necessary if it is true in a set of worlds, and nonfalse in the other worlds [Hanna] |
14680 | Logical possibility contains metaphysical possibility, which contains nomological possibility [Salmon,N] |
14685 | Metaphysical necessity is NOT truth in all (unrestricted) worlds; necessity comes first, and is restricted [Salmon,N] |
14690 | In the S5 account, nested modalities may be unseen, but they are still there [Salmon,N] |
14688 | Without impossible worlds, the unrestricted modality that is metaphysical has S5 logic [Salmon,N] |
11086 | Metaphysical necessity can be 'weak' (same as logical) and 'strong' (based on essences) [Hanna] |
14677 | Metaphysical necessity is said to be unrestricted necessity, true in every world whatsoever [Salmon,N] |
14679 | Bizarre identities are logically but not metaphysically possible, so metaphysical modality is restricted [Salmon,N] |
11084 | Logical necessity is truth in all logically possible worlds, because of laws and concepts [Hanna] |
14681 | Logical necessity is free of constraints, and may accommodate all of S5 logic [Salmon,N] |
10258 | Logical modalities may be acceptable, because they are reducible to satisfaction in models [Shapiro] |
11085 | Nomological necessity is truth in all logically possible worlds with our laws [Hanna] |
14676 | Nomological necessity is expressed with intransitive relations in modal semantics [Salmon,N] |
14689 | Necessity and possibility are not just necessity and possibility according to the actual world [Salmon,N] |
10266 | Why does the 'myth' of possible worlds produce correct modal logic? [Shapiro] |
14674 | Impossible worlds are also ways for things to be [Salmon,N] |
14682 | Denial of impossible worlds involves two different confusions [Salmon,N] |
14687 | Without impossible worlds, how things might have been is the only way for things to be [Salmon,N] |
14683 | Possible worlds rely on what might have been, so they can' be used to define or analyse modality [Salmon,N] |
14675 | Possible worlds just have to be 'maximal', but they don't have to be consistent [Salmon,N] |
14672 | Possible worlds are maximal abstract ways that things might have been [Salmon,N] |
14673 | You can't define worlds as sets of propositions, and then define propositions using worlds [Salmon,N] |
11078 | Intuition is only outside the 'space of reasons' if all reasons are inferential [Hanna] |
11077 | Intuition includes apriority, clarity, modality, authority, fallibility and no inferences [Hanna] |
11080 | Intuition is more like memory, imagination or understanding, than like perception [Hanna] |
11053 | Explanatory reduction is stronger than ontological reduction [Hanna] |
11081 | Imagination grasps abstracta, generates images, and has its own correctness conditions [Hanna] |
10203 | We apprehend small, finite mathematical structures by abstraction from patterns [Shapiro] |
11082 | Should we take the 'depictivist' or the 'descriptivist/propositionalist' view of mental imagery? [Hanna] |
11047 | Hegelian holistic rationality is the capacity to seek coherence [Hanna] |
11048 | Humean Instrumental rationality is the capacity to seek contingent truths [Hanna] |
11046 | Kantian principled rationality is recognition of a priori universal truths [Hanna] |
11067 | Rational animals have a normative concept of necessity [Hanna] |
11068 | One tradition says talking is the essence of rationality; the other says the essence is logic [Hanna] |
11045 | Most psychologists are now cognitivists [Hanna] |
10229 | Simple types can be apprehended through their tokens, via abstraction [Shapiro] |
10217 | We can apprehend structures by focusing on or ignoring features of patterns [Shapiro] |
9554 | We can focus on relations between objects (like baseballers), ignoring their other features [Shapiro] |
10231 | Abstract objects might come by abstraction over an equivalence class of base entities [Shapiro] |