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All the ideas for 'What is Logic?st1=Ian Hacking', 'Rationality in Action' and 'Russell'

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47 ideas

2. Reason / A. Nature of Reason / 1. On Reason
Entailment and validity are relations, but inference is a human activity [Searle]
Theory involves accepting conclusions, and so is a special case of practical reason [Searle]
2. Reason / A. Nature of Reason / 8. Naturalising Reason
Rationality is the way we coordinate our intentionality [Searle]
Rationality is built into the intentionality of the mind, and its means of expression [Searle]
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
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 / 1. Overview of Logic
If complex logic requires rules, then so does basic logic [Searle]
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 / I. Semantics of Logic / 1. Semantics of Logic
In real reasoning semantics gives validity, not syntax [Searle]
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]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / a. Early logicism
Russell needed three extra axioms to reduce maths to logic: infinity, choice and reducibility [Grayling]
7. Existence / C. Structure of Existence / 5. Supervenience / b. Types of supervenience
Users of 'supervenience' blur its causal and constitutive meanings [Searle]
11. Knowledge Aims / A. Knowledge / 4. Belief / c. Aim of beliefs
Our beliefs are about things, not propositions (which are the content of the belief) [Searle]
A belief is a commitment to truth [Searle]
We can't understand something as a lie if beliefs aren't commitment to truth [Searle]
11. Knowledge Aims / B. Certain Knowledge / 4. The Cogito
Thinking must involve a self, not just an "it" [Searle]
12. Knowledge Sources / A. A Priori Knowledge / 2. Self-Evidence
Two propositions might seem self-evident, but contradict one another [Grayling]
13. Knowledge Criteria / A. Justification Problems / 1. Justification / a. Justification issues
Reasons can either be facts in the world, or intentional states [Searle]
13. Knowledge Criteria / C. External Justification / 1. External Justification
In the past people had a reason not to smoke, but didn't realise it [Searle]
13. Knowledge Criteria / C. External Justification / 2. Causal Justification
Causes (usually events) are not the same as reasons (which are never events) [Searle]
16. Persons / A. Concept of a Person / 2. Persons as Responsible
Being held responsible for past actions makes no sense without personal identity [Searle]
16. Persons / A. Concept of a Person / 3. Persons as Reasoners
Giving reasons for action requires reference to a self [Searle]
A 'self' must be capable of conscious reasonings about action [Searle]
An intentional, acting, rational being must have a self [Searle]
16. Persons / A. Concept of a Person / 4. Persons as Agents
Action requires a self, even though perception doesn't [Searle]
16. Persons / B. Nature of the Self / 1. Self and Consciousness
A self must at least be capable of consciousness [Searle]
Selfs are conscious, enduring, reasonable, active, free, and responsible [Searle]
16. Persons / B. Nature of the Self / 4. Presupposition of Self
The self is neither an experience nor a thing experienced [Searle]
16. Persons / B. Nature of the Self / 5. Self as Associations
The bundle must also have agency in order to act, and a self to act rationally [Searle]
16. Persons / F. Free Will / 4. For Free Will
Rational decision making presupposes free will [Searle]
Free will is most obvious when we choose between several reasons for an action [Searle]
We freely decide whether to make a reason for action effective [Searle]
20. Action / C. Motives for Action / 1. Acting on Desires
Preferences can result from deliberation, not just precede it [Searle]
20. Action / C. Motives for Action / 3. Acting on Reason / a. Practical reason
We don't accept practical reasoning if the conclusion is unpalatable [Searle]
20. Action / C. Motives for Action / 3. Acting on Reason / b. Intellectualism
The essence of humanity is desire-independent reasons for action [Searle]
Only an internal reason can actually motivate the agent to act [Searle]
22. Metaethics / B. Value / 1. Nature of Value / b. Fact and value
If it is true, you ought to believe it [Searle]
If this is a man, you ought to accept similar things as men [Searle]
23. Ethics / B. Contract Ethics / 3. Promise Keeping
Promises hold because I give myself a reason, not because it is an institution [Searle]
23. Ethics / D. Deontological Ethics / 2. Duty
'Ought' implies that there is a reason to do something [Searle]