Combining Texts

All the ideas for 'Meno', 'Introduction to Mathematical Logic' and 'Letters to Wagner'

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32 ideas

1. Philosophy / A. Wisdom / 1. Nature of Wisdom
1922 Spiritual qualities only become advantageous with the growth of wisdom [Plato]
4. Formal Logic / B. Propositional Logic PL / 1. Propositional Logic
17749 Post proved the consistency of propositional logic in 1921 [Walicki]
17765 Propositional language can only relate statements as the same or as different [Walicki]
4. Formal Logic / B. Propositional Logic PL / 3. Truth Tables
17764 Boolean connectives are interpreted as functions on the set {1,0} [Walicki]
4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set
17752 The empty set is useful for defining sets by properties, when the members are not yet known [Walicki]
17753 The empty set avoids having to take special precautions in case members vanish [Walicki]
4. Formal Logic / F. Set Theory ST / 6. Ordering in Sets
17759 Ordinals play the central role in set theory, providing the model of well-ordering [Walicki]
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
17741 To determine the patterns in logic, one must identify its 'building blocks' [Walicki]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
17747 A 'model' of a theory specifies interpreting a language in a domain to make all theorems true [Walicki]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
17748 The L-S Theorem says no theory (even of reals) says more than a natural number theory [Walicki]
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
17761 A compact axiomatisation makes it possible to understand a field as a whole [Walicki]
17763 Axiomatic systems are purely syntactic, and do not presuppose any interpretation [Walicki]
5. Theory of Logic / L. Paradox / 2. Aporiai
11259 How can you seek knowledge of something if you don't know it? [Plato]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
17758 Ordinals are transitive sets of transitive sets; or transitive sets totally ordered by inclusion [Walicki]
17755 Ordinals are the empty set, union with the singleton, and any arbitrary union of ordinals [Walicki]
17756 The union of finite ordinals is the first 'limit ordinal'; 2ω is the second... [Walicki]
17760 Two infinite ordinals can represent a single infinite cardinal [Walicki]
17757 Members of ordinals are ordinals, and also subsets of ordinals [Walicki]
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
17762 In non-Euclidean geometry, all Euclidean theorems are valid that avoid the fifth postulate [Walicki]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / f. Mathematical induction
17754 Inductive proof depends on the choice of the ordering [Walicki]
10. Modality / A. Necessity / 2. Nature of Necessity
17742 Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki]
11. Knowledge Aims / A. Knowledge / 3. Value of Knowledge
20219 True opinions only become really valuable when they are tied down by reasons [Plato]
12. Knowledge Sources / A. A Priori Knowledge / 3. Innate Knowledge / b. Recollection doctrine
5985 Seeking and learning are just recollection [Plato]
5986 The slave boy learns geometry from questioning, not teaching, so it is recollection [Plato]
13. Knowledge Criteria / A. Justification Problems / 1. Justification / b. Need for justification
1923 As a guide to action, true opinion is as good as knowledge [Plato]
13. Knowledge Criteria / D. Scepticism / 6. Scepticism Critique
1919 You don't need to learn what you know, and how do you seek for what you don't know? [Plato]
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / d. Teaching virtue
1927 It seems that virtue is neither natural nor taught, but is a divine gift [Plato]
1913 Is virtue taught, or achieved by practice, or a natural aptitude, or what? [Plato]
1921 If virtue is a type of knowledge then it ought to be taught [Plato]
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / j. Unity of virtue
1916 Even if virtues are many and various, they must have something in common to make them virtues [Plato]
1918 How can you know part of virtue without knowing the whole? [Plato]
26. Natural Theory / A. Speculations on Nature / 7. Later Matter Theories / a. Early Modern matter
19436 Bare or primary matter is passive; it is clothed or secondary matter which contains action [Leibniz]