Combining Texts

All the ideas for 'What is Logic?st1=Ian Hacking', 'Intro to I: Classical Logic' and 'The Disorder of Things'

expand these ideas     |    start again     |     specify just one area for these texts

29 ideas

2. Reason / D. Definition / 3. Types of Definition
13838 A decent modern definition should always imply a semantics [Hacking]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / d. Basic theorems of PL
13833 'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking]
13834 Gentzen's Cut Rule (or transitivity of deduction) is 'If A |- B and B |- C, then A |- C' [Hacking]
13835 Only Cut reduces complexity, so logic is constructive without it, and it can be dispensed with [Hacking]
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
13845 The various logics are abstractions made from terms like 'if...then' in English [Hacking]
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
13840 First-order logic is the strongest complete compact theory with Löwenheim-Skolem [Hacking]
13844 A limitation of first-order logic is that it cannot handle branching quantifiers [Hacking]
5. Theory of Logic / A. Overview of Logic / 6. Classical Logic
9463 Classical logic is bivalent, has excluded middle, and only quantifies over existent objects [Jacquette]
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
13842 Second-order completeness seems to need intensional entities and possible worlds [Hacking]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
13837 With a pure notion of truth and consequence, the meanings of connectives are fixed syntactically [Hacking]
5. Theory of Logic / E. Structures of Logic / 4. Variables in Logic
13839 Perhaps variables could be dispensed with, by arrows joining places in the scope of quantifiers [Hacking]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
13843 If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking]
7. Existence / E. Categories / 1. Categories
17377 All descriptive language is classificatory [Dupré]
7. Existence / E. Categories / 2. Categorisation
17376 We should aim for a classification which tells us as much as possible about the object [Dupré]
9. Objects / D. Essence of Objects / 8. Essence as Explanatory
17390 Natural kinds don't need essentialism to be explanatory [Dupré]
9. Objects / D. Essence of Objects / 10. Essence as Species
17389 A species might have its essential genetic mechanism replaced by a new one [Dupré]
17388 It seems that species lack essential properties, so they can't be natural kinds [Dupré]
14. Science / A. Basis of Science / 4. Prediction
17374 The possibility of prediction rests on determinism [Dupré]
18. Thought / C. Content / 5. Twin Earth
17378 Presumably molecular structure seems important because we never have the Twin Earth experience [Dupré]
26. Natural Theory / B. Natural Kinds / 1. Natural Kinds
17381 Phylogenetics involves history, and cladism rests species on splits in lineage [Dupré]
17385 Kinds don't do anything (including evolve) because they are abstract [Dupré]
26. Natural Theory / B. Natural Kinds / 7. Critique of Kinds
17375 Natural kinds are decided entirely by the intentions of our classification [Dupré]
17379 Borders between species are much less clear in vegetables than among animals [Dupré]
17384 Even atoms of an element differ, in the energy levels of their electrons [Dupré]
17387 Ecologists favour classifying by niche, even though that can clash with genealogy [Dupré]
17382 Cooks, unlike scientists, distinguish garlic from onions [Dupré]
17380 Wales may count as fish [Dupré]
27. Natural Reality / G. Biology / 5. Species
17383 Species are the lowest-level classification in biology [Dupré]
17386 The theory of evolution is mainly about species [Dupré]