Combining Texts

All the ideas for 'Introduction to Mathematical Logic', 'Euthyphro' and 'Towards a Critique of Hegel's Philosophy'

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29 ideas

1. Philosophy / C. History of Philosophy / 1. History of Philosophy
19441 All philosophies presuppose their historical moment, and arise from it [Feuerbach]
1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / a. Philosophy as worldly
19442 I don't study Plato for his own sake; the primary aim is always understanding [Feuerbach]
2. Reason / C. Styles of Reason / 1. Dialectic
19445 A dialectician has to be his own opponent [Feuerbach]
19444 Each proposition has an antithesis, and truth exists as its refutation [Feuerbach]
3. Truth / A. Truth Problems / 3. Value of Truth
19443 Truth forges an impersonal unity between people [Feuerbach]
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
17763 Axiomatic systems are purely syntactic, and do not presuppose any interpretation [Walicki]
17761 A compact axiomatisation makes it possible to understand a field as a whole [Walicki]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
17757 Members of ordinals are ordinals, and also subsets of ordinals [Walicki]
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]
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]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / e. Ontological commitment problems
19446 To our consciousness it is language which looks unreal [Feuerbach]
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 / C. Knowing Reality / 3. Idealism / d. Absolute idealism
19447 The Absolute is the 'and' which unites 'spirit and nature' [Feuerbach]
13. Knowledge Criteria / E. Relativism / 6. Relativism Critique
335 Do the gods also hold different opinions about what is right and honourable? [Plato]
28. God / A. Divine Nature / 6. Divine Morality / b. Euthyphro question
336 Is what is pious loved by the gods because it is pious, or is it pious because they love it? (the 'Euthyphro Question') [Plato]
337 It seems that the gods love things because they are pious, rather than making them pious by loving them [Plato]