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All the ideas for 'What is Logic?st1=Ian Hacking', 'The Enneads' and 'Guide to Ground'

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48 ideas

1. Philosophy / E. Nature of Metaphysics / 5. Metaphysics beyond Science
Realist metaphysics concerns what is real; naive metaphysics concerns natures of things [Fine,K]
2. Reason / D. Definition / 3. Types of Definition
A decent modern definition should always imply a semantics [Hacking]
3. Truth / B. Truthmakers / 3. Truthmaker Maximalism
Truths need not always have their source in what exists [Fine,K]
3. Truth / B. Truthmakers / 7. Making Modal Truths
If the truth-making relation is modal, then modal truths will be grounded in anything [Fine,K]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / d. Basic theorems of PL
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]
'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [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 / B. Logical Consequence / 1. Logical Consequence
Logical consequence is verification by a possible world within a truth-set [Fine,K]
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 / f. Primary being
Being is the product of pure intellect [Plotinus]
The One does not exist, but is the source of all existence [Plotinus]
The One is a principle which transcends Being [Plotinus]
7. Existence / A. Nature of Existence / 3. Being / g. Particular being
Number determines individual being [Plotinus]
7. Existence / C. Structure of Existence / 1. Grounding / a. Nature of grounding
2+2=4 is necessary if it is snowing, but not true in virtue of the fact that it is snowing [Fine,K]
If you say one thing causes another, that leaves open that the 'other' has its own distinct reality [Fine,K]
An immediate ground is the next lower level, which gives the concept of a hierarchy [Fine,K]
'Strict' ground moves down the explanations, but 'weak' ground can move sideways [Fine,K]
We learn grounding from what is grounded, not what does the grounding [Fine,K]
7. Existence / C. Structure of Existence / 1. Grounding / b. Relata of grounding
Ground is best understood as a sentence operator, rather than a relation between predicates [Fine,K]
If grounding is a relation it must be between entities of the same type, preferably between facts [Fine,K]
7. Existence / C. Structure of Existence / 1. Grounding / c. Grounding and explanation
Only metaphysical grounding must be explained by essence [Fine,K]
Philosophical explanation is largely by ground (just as cause is used in science) [Fine,K]
7. Existence / C. Structure of Existence / 1. Grounding / d. Grounding and reduction
We can only explain how a reduction is possible if we accept the concept of ground [Fine,K]
7. Existence / D. Theories of Reality / 8. Facts / a. Facts
Facts, such as redness and roundness of a ball, can be 'fused' into one fact [Fine,K]
9. Objects / E. Objects over Time / 5. Temporal Parts
Even a three-dimensionalist might identify temporal parts, in their thinking [Fine,K]
10. Modality / C. Sources of Modality / 1. Sources of Necessity
Every necessary truth is grounded in the nature of something [Fine,K]
Each basic modality has its 'own' explanatory relation [Fine,K]
14. Science / D. Explanation / 2. Types of Explanation / a. Types of explanation
Is there metaphysical explanation (as well as causal), involving a constitutive form of determination? [Fine,K]
We explain by identity (what it is), or by truth (how things are) [Fine,K]
15. Nature of Minds / A. Nature of Mind / 5. Unity of Mind
If soul was like body, its parts would be separate, without communication [Plotinus]
15. Nature of Minds / B. Features of Minds / 2. Unconscious Mind
The movement of Soul is continuous, but we are only aware of the parts of it that are sensed [Plotinus]
16. Persons / D. Continuity of the Self / 2. Mental Continuity / b. Self as mental continuity
A person is the whole of their soul [Plotinus]
17. Mind and Body / A. Mind-Body Dualism / 1. Dualism
Our soul has the same ideal nature as the oldest god, and is honourable above the body [Plotinus]
The soul is outside of all of space, and has no connection to the bodily order [Plotinus]
17. Mind and Body / D. Property Dualism / 5. Supervenience of mind
If mind supervenes on the physical, it may also explain the physical (and not vice versa) [Fine,K]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / b. Rational ethics
The Soul reasons about the Right, so there must be some permanent Right about which it reasons [Plotinus]
22. Metaethics / C. The Good / 2. Happiness / a. Nature of happiness
Ecstasy is for the neo-Platonist the highest psychological state of man [Plotinus, by Feuerbach]
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / e. The One
How can multiple existence arise from the unified One? [Plotinus]
Because the One is immobile, it must create by radiation, light the sun producing light [Plotinus]
Soul is the logos of Nous, just as Nous is the logos of the One [Plotinus]
28. God / B. Proving God / 3. Proofs of Evidence / b. Teleological Proof
Soul is author of all of life, and of the stars, and it gives them law and movement [Plotinus]
29. Religion / D. Religious Issues / 2. Immortality / b. Soul
Even the soul is secondary to the Intellectual-Principle [Nous], of which soul is an utterance [Plotinus]