Combining Texts

All the ideas for 'What is Logic?st1=Ian Hacking', 'Identity and Essence' and 'The Vocation of Man'

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48 ideas

2. Reason / A. Nature of Reason / 8. Naturalising Reason
The need to act produces consciousness, and practical reason is the root of all reason [Fichte]
2. Reason / B. Laws of Thought / 2. Sufficient Reason
Sufficient reason makes the transition from the particular to the general [Fichte]
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]
8. Modes of Existence / B. Properties / 1. Nature of Properties
Each object has a precise number of properties, each to a precise degree [Fichte]
8. Modes of Existence / C. Powers and Dispositions / 2. Powers as Basic
The principle of activity and generation is found in a self-moving basic force [Fichte]
9. Objects / A. Existence of Objects / 5. Individuation / a. Individuation
Indiscernibility is a necessary and sufficient condition for identity [Brody]
9. Objects / A. Existence of Objects / 5. Individuation / e. Individuation by kind
Brody bases sortal essentialism on properties required throughout something's existence [Brody, by Mackie,P]
9. Objects / C. Structure of Objects / 2. Hylomorphism / a. Hylomorphism
Modern emphasis is on properties had essentially; traditional emphasis is on sort-defining properties [Brody]
9. Objects / D. Essence of Objects / 5. Essence as Kind
A sortal essence is a property which once possessed always possessed [Brody, by Mackie,P]
Maybe essential properties are those which determine a natural kind? [Brody]
9. Objects / D. Essence of Objects / 6. Essence as Unifier
De re essentialism standardly says all possible objects identical with a have a's essential properties [Brody]
9. Objects / D. Essence of Objects / 7. Essence and Necessity / a. Essence as necessary properties
Essentially, a has P, always had P, must have had P, and has never had a future without P [Brody]
An object having a property essentially is equivalent to its having it necessarily [Brody]
9. Objects / D. Essence of Objects / 8. Essence as Explanatory
Essentialism is justified if the essential properties of things explain their other properties [Brody]
9. Objects / D. Essence of Objects / 12. Essential Parts
Mereological essentialism says that every part that ensures the existence is essential [Brody]
9. Objects / E. Objects over Time / 12. Origin as Essential
Interrupted objects have two first moments of existence, which could be two beginnings [Brody]
9. Objects / F. Identity among Objects / 7. Indiscernible Objects
a and b share all properties; so they share being-identical-with-a; so a = b [Brody]
10. Modality / E. Possible worlds / 3. Transworld Objects / b. Rigid designation
Identity across possible worlds is prior to rigid designation [Brody]
11. Knowledge Aims / C. Knowing Reality / 3. Idealism / b. Transcendental idealism
I am myself, but not the external object; so I only sense myself, and not the object [Fichte]
11. Knowledge Aims / C. Knowing Reality / 3. Idealism / d. Absolute idealism
Self-consciousness is the basis of knowledge, and knowing something is knowing myself [Fichte]
There is nothing to say about anything which is outside my consciousness [Fichte]
Awareness of reality comes from the free activity of consciousness [Fichte]
12. Knowledge Sources / B. Perception / 6. Inference in Perception
I immediately know myself, and anything beyond that is an inference [Fichte]
12. Knowledge Sources / E. Direct Knowledge / 2. Intuition
Faith is not knowledge; it is a decision of the will [Fichte]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / b. Basic beliefs
Knowledge can't be its own foundation; there has to be regress of higher and higher authorities [Fichte]
15. Nature of Minds / A. Nature of Mind / 1. Mind / c. Features of mind
Consciousness has two parts, passively receiving sensation, and actively causing productions [Fichte]
15. Nature of Minds / B. Features of Minds / 7. Blindsight
We can't know by sight or hearing without realising that we are doing so [Fichte]
16. Persons / B. Nature of the Self / 4. Presupposition of Self
Consciousness of external things is always accompanied by an unnoticed consciousness of self [Fichte]
16. Persons / F. Free Will / 1. Nature of Free Will
Forming purposes is absolutely free, and produces something from nothing [Fichte]
The capacity for freedom is above the laws of nature, with its own power of purpose and will [Fichte]
16. Persons / F. Free Will / 2. Sources of Free Will
I want independent control of the fundamental cause of my decisions [Fichte]
17. Mind and Body / A. Mind-Body Dualism / 3. Panpsychism
Nature contains a fundamental force of thought [Fichte]
20. Action / B. Preliminaries of Action / 2. Willed Action / a. Will to Act
The will is awareness of one of our inner natural forces [Fichte]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / e. Human nature
I cannot change the nature which has been determined for me [Fichte]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / g. Will to power
The self is, apart from outward behaviour, a drive in your nature [Fichte]
22. Metaethics / B. Value / 2. Values / g. Love
If life lacks love it becomes destruction [Fichte]
23. Ethics / F. Existentialism / 6. Authentic Self
Freedom means making yourself become true to your essential nature [Fichte]
26. Natural Theory / A. Speculations on Nature / 1. Nature
Nature is wholly interconnected, and the tiniest change affects everything [Fichte]