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All the ideas for 'What is Logic?st1=Ian Hacking', 'Why there isn't a ready-made world' and 'Science of Logic'

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43 ideas

1. Philosophy / E. Nature of Metaphysics / 6. Metaphysics as Conceptual
If we start with indeterminate being, we arrive at being and nothing as a united pair [Hegel, by Houlgate]
Thought about being leads to a string of other concepts, like becoming, quantity, specificity, causality... [Hegel, by Houlgate]
We must start with absolute abstraction, with no presuppositions, so we start with pure being [Hegel]
2. Reason / A. Nature of Reason / 5. Objectivity
Objectivity is not by correspondence, but by the historical determined necessity of Geist [Hegel, by Pinkard]
2. Reason / B. Laws of Thought / 3. Non-Contradiction
Being and nothing are the same and not the same, which is the identity of identity and non-identity [Hegel]
The so-called world is filled with contradiction [Hegel]
2. Reason / C. Styles of Reason / 1. Dialectic
Dialectic is the instability of thoughts generating their opposite, and then new more complex thoughts [Hegel, by Houlgate]
Hegel's dialectic is not thesis-antithesis-synthesis, but usually negation of negation of the negation [Hegel, by Moore,AW]
2. Reason / D. Definition / 3. Types of Definition
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
'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking]
Gentzen's Cut Rule (or transitivity of deduction) is 'If A |- B and B |- C, then A |- C' [Hacking]
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
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
First-order logic is the strongest complete compact theory with Löwenheim-Skolem [Hacking]
A limitation of first-order logic is that it cannot handle branching quantifiers [Hacking]
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
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
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
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
If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking]
7. Existence / A. Nature of Existence / 3. Being / d. Non-being
To grasp an existence, we must consider its non-existence [Hegel, by Houlgate]
Nothing exists, as thinkable and expressible [Hegel]
7. Existence / A. Nature of Existence / 3. Being / e. Being and nothing
Thinking of nothing is not the same as simply not thinking [Hegel, by Houlgate]
7. Existence / C. Structure of Existence / 1. Grounding / a. Nature of grounding
The ground of a thing is not another thing, but the first thing's substance or rational concept [Hegel, by Houlgate]
7. Existence / D. Theories of Reality / 2. Realism
Kant's thing-in-itself is just an abstraction from our knowledge; things only exist for us [Hegel, by Bowie]
Hegel believe that the genuine categories reveal things in themselves [Hegel, by Houlgate]
Metaphysical realism is committed to there being one ultimate true theory [Putnam]
7. Existence / D. Theories of Reality / 4. Anti-realism
It is an illusion to think there could be one good scientific theory of reality [Putnam]
8. Modes of Existence / A. Relations / 2. Internal Relations
The nature of each category relates itself to another [Hegel]
9. Objects / B. Unity of Objects / 3. Unity Problems / c. Statue and clay
Shape is essential relative to 'statue', but not essential relative to 'clay' [Putnam]
11. Knowledge Aims / B. Certain Knowledge / 1. Certainty
In absolute knowing, the gap between object and oneself closes, producing certainty [Hegel]
11. Knowledge Aims / C. Knowing Reality / 3. Idealism / d. Absolute idealism
The 'absolute idea' is when all the contradictions are exhausted [Hegel, by Bowie]
Hegel, unlike Kant, said how things appear is the same as how things are [Hegel, by Moore,AW]
Hegel's non-subjective idealism is the unity of subjective and objective viewpoints [Hegel, by Pinkard]
Hegel claimed his system was about the world, but it only mapped conceptual interdependence [Pinkard on Hegel]
The Absolute is the primitive system of concepts which are actualised [Hegel, by Gardner]
Authentic thinking and reality have the same content [Hegel]
The absolute idea is being, imperishable life, self-knowing truth, and all truth [Hegel]
The absolute idea is the great unity of the infinite system of concepts [Hegel, by Moore,AW]
12. Knowledge Sources / B. Perception / 4. Sense Data / b. Nature of sense-data
The old view that sense data are independent of mind is quite dotty [Putnam]
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / a. Coherence as justification
Hegel's 'absolute idea' is the interdependence of all truths to justify any of them [Hegel, by Bowie]
18. Thought / D. Concepts / 1. Concepts / a. Nature of concepts
Every concept depends on the counter-concepts of what it is not [Hegel, by Bowie]
19. Language / E. Analyticity / 4. Analytic/Synthetic Critique
When we explicate the category of being, we watch a new category emerge [Hegel, by Houlgate]
26. Natural Theory / C. Causation / 8. Particular Causation / d. Selecting the cause
An alien might think oxygen was the main cause of a forest fire [Putnam]