Combining Texts

All the ideas for 'Necessary Existents', 'Ideas: intro to pure phenomenology' and 'A Tour through Mathematical Logic'

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46 ideas

1. Philosophy / H. Continental Philosophy / 2. Phenomenology
Phenomenology studies different types of correlation between consciousness and its objects [Husserl, by Bernet]
Phenomenology aims to validate objects, on the basis of intentional intuitive experience [Husserl, by Bernet]
Phenomenology needs absolute reflection, without presuppositions [Husserl]
There can only be a science of fluctuating consciousness if it focuses on stable essences [Husserl, by Bernet]
Husserl saw transcendental phenomenology as idealist, in its construction of objects [Husserl, by Bernet]
Start philosophising with no preconceptions, from the intuitively non-theoretical self-given [Husserl]
Epoché or 'bracketing' is refraining from judgement, even when some truths are certain [Husserl]
'Bracketing' means no judgements at all about spatio-temporal existence [Husserl]
After everything is bracketed, consciousness still has a unique being of its own [Husserl]
Phenomenology describes consciousness, in the light of pure experiences [Husserl]
2. Reason / D. Definition / 13. Against Definition
The use of mathematical-style definitions in philosophy is fruitless and harmful [Husserl]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / b. Terminology of PL
A 'tautology' must include connectives [Wolf,RS]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / c. Derivation rules of PL
Deduction Theorem: T∪{P}|-Q, then T|-(P→Q), which justifies Conditional Proof [Wolf,RS]
4. Formal Logic / C. Predicate Calculus PC / 2. Tools of Predicate Calculus / d. Universal quantifier ∀
Universal Specification: ∀xP(x) implies P(t). True for all? Then true for an instance [Wolf,RS]
Universal Generalization: If we prove P(x) with no special assumptions, we can conclude ∀xP(x) [Wolf,RS]
4. Formal Logic / C. Predicate Calculus PC / 2. Tools of Predicate Calculus / e. Existential quantifier ∃
Existential Generalization (or 'proof by example'): if we can say P(t), then we can say something is P [Wolf,RS]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / e. Axiom of the Empty Set IV
Empty Set: ∃x∀y ¬(y∈x). The unique empty set exists [Wolf,RS]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / n. Axiom of Comprehension
Comprehension Axiom: if a collection is clearly specified, it is a set [Wolf,RS]
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
In first-order logic syntactic and semantic consequence (|- and |=) nicely coincide [Wolf,RS]
First-order logic is weakly complete (valid sentences are provable); we can't prove every sentence or its negation [Wolf,RS]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
Model theory uses sets to show that mathematical deduction fits mathematical truth [Wolf,RS]
Model theory reveals the structures of mathematics [Wolf,RS]
Model theory 'structures' have a 'universe', some 'relations', some 'functions', and some 'constants' [Wolf,RS]
First-order model theory rests on completeness, compactness, and the Löwenheim-Skolem-Tarski theorem [Wolf,RS]
5. Theory of Logic / J. Model Theory in Logic / 2. Isomorphisms
An 'isomorphism' is a bijection that preserves all structural components [Wolf,RS]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
The LST Theorem is a serious limitation of first-order logic [Wolf,RS]
5. Theory of Logic / K. Features of Logics / 4. Completeness
If a theory is complete, only a more powerful language can strengthen it [Wolf,RS]
5. Theory of Logic / K. Features of Logics / 10. Monotonicity
Most deductive logic (unlike ordinary reasoning) is 'monotonic' - we don't retract after new givens [Wolf,RS]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
An ordinal is an equivalence class of well-orderings, or a transitive set whose members are transitive [Wolf,RS]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
Modern mathematics has unified all of its objects within set theory [Wolf,RS]
7. Existence / A. Nature of Existence / 3. Being / a. Nature of Being
Our goal is to reveal a new hidden region of Being [Husserl]
7. Existence / A. Nature of Existence / 3. Being / h. Dasein (being human)
As a thing and its perception are separated, two modes of Being emerge [Husserl]
7. Existence / D. Theories of Reality / 3. Reality
The World is all experiencable objects [Husserl]
7. Existence / D. Theories of Reality / 4. Anti-realism
Absolute reality is an absurdity [Husserl]
9. Objects / D. Essence of Objects / 5. Essence as Kind
The sense of anything contingent has a purely apprehensible essence or Eidos [Husserl]
9. Objects / D. Essence of Objects / 9. Essence and Properties
Imagine an object's properties varying; the ones that won't vary are the essential ones [Husserl, by Vaidya]
11. Knowledge Aims / B. Certain Knowledge / 4. The Cogito
The physical given, unlike the mental given, could be non-existing [Husserl]
12. Knowledge Sources / A. A Priori Knowledge / 2. Self-Evidence
Feelings of self-evidence (and necessity) are just the inventions of theory [Husserl]
12. Knowledge Sources / E. Direct Knowledge / 2. Intuition
Direct 'seeing' by consciousness is the ultimate rational legitimation [Husserl]
12. Knowledge Sources / E. Direct Knowledge / 4. Memory
The phenomena of memory are given in the present, but as being past [Husserl, by Bernet]
13. Knowledge Criteria / D. Scepticism / 6. Scepticism Critique
Natural science has become great by just ignoring ancient scepticism [Husserl]
15. Nature of Minds / A. Nature of Mind / 4. Other Minds / c. Knowing other minds
We know another's mind via bodily expression, while also knowing it is inaccessible [Husserl, by Bernet]
15. Nature of Minds / B. Features of Minds / 1. Consciousness / b. Essence of consciousness
Pure consciousness is a sealed off system of actual Being [Husserl]
16. Persons / C. Self-Awareness / 2. Knowing the Self
We never meet the Ego, as part of experience, or as left over from experience [Husserl]
19. Language / D. Propositions / 3. Concrete Propositions
Propositions (such as 'that dog is barking') only exist if their items exist [Williamson]
22. Metaethics / B. Value / 1. Nature of Value / b. Fact and value
Only facts follow from facts [Husserl]