Combining Philosophers

All the ideas for Engelbretsen,G/Sayward,C, C.I. Lewis and Carl Friedrich Gauss

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24 ideas

4. Formal Logic / A. Syllogistic Logic / 1. Aristotelian Logic
13913 The four 'perfect syllogisms' are called Barbara, Celarent, Darii and Ferio [Engelbretsen/Sayward]
13914 Syllogistic logic has one rule: what is affirmed/denied of wholes is affirmed/denied of their parts [Engelbretsen/Sayward]
4. Formal Logic / A. Syllogistic Logic / 2. Syllogistic Logic
13915 Syllogistic can't handle sentences with singular terms, or relational terms, or compound sentences [Engelbretsen/Sayward]
4. Formal Logic / A. Syllogistic Logic / 3. Term Logic
13916 Term logic uses expression letters and brackets, and '-' for negative terms, and '+' for compound terms [Engelbretsen/Sayward]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / h. System S5
7791 The simplest of the logics based on possible worlds is Lewis's S5 [Lewis,CI, by Girle]
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
9358 There are several logics, none of which will ever derive falsehoods from truth [Lewis,CI]
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
13850 In modern logic all formal validity can be characterised syntactically [Engelbretsen/Sayward]
5. Theory of Logic / A. Overview of Logic / 6. Classical Logic
13849 Classical logic rests on truth and models, where constructivist logic rests on defence and refutation [Engelbretsen/Sayward]
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
9357 Excluded middle is just our preference for a simplified dichotomy in experience [Lewis,CI]
5. Theory of Logic / D. Assumptions for Logic / 4. Identity in Logic
13851 Unlike most other signs, = cannot be eliminated [Engelbretsen/Sayward]
5. Theory of Logic / F. Referring in Logic / 1. Naming / a. Names
9364 Names represent a uniformity in experience, or they name nothing [Lewis,CI]
5. Theory of Logic / K. Features of Logics / 5. Incompleteness
13852 Axioms are ω-incomplete if the instances are all derivable, but the universal quantification isn't [Engelbretsen/Sayward]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / d. Actual infinite
10855 Actual infinities are not allowed in mathematics - only limits which may increase without bound [Gauss]
10. Modality / A. Necessity / 2. Nature of Necessity
11002 Equating necessity with informal provability is the S4 conception of necessity [Lewis,CI, by Read]
10. Modality / A. Necessity / 11. Denial of Necessity
9362 Necessary truths are those we will maintain no matter what [Lewis,CI]
10. Modality / B. Possibility / 8. Conditionals / a. Conditionals
7803 Modal logic began with translation difficulties for 'If...then' [Lewis,CI, by Girle]
12. Knowledge Sources / A. A Priori Knowledge / 7. A Priori from Convention
9365 We can maintain a priori principles come what may, but we can also change them [Lewis,CI]
12. Knowledge Sources / E. Direct Knowledge / 4. Memory
21500 We rely on memory for empirical beliefs because they mutually support one another [Lewis,CI]
21501 If we doubt memories we cannot assess our doubt, or what is being doubted [Lewis,CI]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / a. Foundationalism
6556 If anything is to be probable, then something must be certain [Lewis,CI]
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / b. Pro-coherentism
21498 Congruents assertions increase the probability of each individual assertion in the set [Lewis,CI]
18. Thought / C. Content / 8. Intension
5828 Extension is the class of things, intension is the correct definition of the thing, and intension determines extension [Lewis,CI]
18. Thought / E. Abstraction / 2. Abstracta by Selection
9361 We have to separate the mathematical from physical phenomena by abstraction [Lewis,CI]
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / a. Scientific essentialism
9363 Science seeks classification which will discover laws, essences, and predictions [Lewis,CI]