Combining Texts

All the ideas for 'Sweet Dreams', 'Negation' and 'What is Logic?'

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30 ideas

2. Reason / A. Nature of Reason / 9. Limits of Reason
Inconsistency doesn't prevent us reasoning about some system [Mares]
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]
4. Formal Logic / E. Nonclassical Logics / 2. Intuitionist Logic
Intuitionist logic looks best as natural deduction [Mares]
Intuitionism as natural deduction has no rule for negation [Mares]
4. Formal Logic / E. Nonclassical Logics / 3. Many-Valued Logic
Three-valued logic is useful for a theory of presupposition [Mares]
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 / 6. Classical Logic
Material implication (and classical logic) considers nothing but truth values for implications [Mares]
In classical logic the connectives can be related elegantly, as in De Morgan's laws [Mares]
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 / D. Assumptions for Logic / 1. Bivalence
Excluded middle standardly implies bivalence; attacks use non-contradiction, De M 3, or double negation [Mares]
Standard disjunction and negation force us to accept the principle of bivalence [Mares]
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]
The connectives are studied either through model theory or through proof theory [Mares]
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 / H. Proof Systems / 4. Natural Deduction
Many-valued logics lack a natural deduction system [Mares]
5. Theory of Logic / I. Semantics of Logic / 1. Semantics of Logic
Situation semantics for logics: not possible worlds, but information in situations [Mares]
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]
5. Theory of Logic / K. Features of Logics / 2. Consistency
Consistency is semantic, but non-contradiction is syntactic [Mares]
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / b. Intuitionism
For intuitionists there are not numbers and sets, but processes of counting and collecting [Mares]
15. Nature of Minds / B. Features of Minds / 5. Qualia / c. Explaining qualia
Obviously there can't be a functional anaylsis of qualia if they are defined by intrinsic properties [Dennett]
16. Persons / E. Rejecting the Self / 4. Denial of the Self
The work done by the 'homunculus in the theatre' must be spread amongst non-conscious agencies [Dennett]
17. Mind and Body / E. Mind as Physical / 2. Reduction of Mind
Intelligent agents are composed of nested homunculi, of decreasing intelligence, ending in machines [Dennett]
17. Mind and Body / E. Mind as Physical / 3. Eliminativism
I don't deny consciousness; it just isn't what people think it is [Dennett]
18. Thought / B. Mechanics of Thought / 6. Artificial Thought / a. Artificial Intelligence
What matters about neuro-science is the discovery of the functional role of the chemistry [Dennett]
19. Language / C. Assigning Meanings / 2. Semantics
In 'situation semantics' our main concepts are abstracted from situations [Mares]