Combining Texts

All the ideas for 'Thinking About Logic', 'Dialogues Concerning Natural Religion' and 'Phenomenal and Perceptual Concepts'

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68 ideas

2. Reason / E. Argument / 3. Analogy
An analogy begins to break down as soon as the two cases differ [Hume]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / c. Derivation rules of PL
Three traditional names of rules are 'Simplification', 'Addition' and 'Disjunctive Syllogism' [Read]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / a. Systems of modal logic
Necessity is provability in S4, and true in all worlds in S5 [Read]
4. Formal Logic / E. Nonclassical Logics / 4. Fuzzy Logic
There are fuzzy predicates (and sets), and fuzzy quantifiers and modifiers [Read]
4. Formal Logic / E. Nonclassical Logics / 6. Free Logic
Same say there are positive, negative and neuter free logics [Read]
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / c. Logical sets
Realisms like the full Comprehension Principle, that all good concepts determine sets [Read]
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
Not all validity is captured in first-order logic [Read]
5. Theory of Logic / A. Overview of Logic / 6. Classical Logic
The non-emptiness of the domain is characteristic of classical logic [Read]
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
Semantics must precede proof in higher-order logics, since they are incomplete [Read]
5. Theory of Logic / A. Overview of Logic / 8. Logic of Mathematics
We should exclude second-order logic, precisely because it captures arithmetic [Read]
5. Theory of Logic / B. Logical Consequence / 1. Logical Consequence
A theory of logical consequence is a conceptual analysis, and a set of validity techniques [Read]
Logical consequence isn't just a matter of form; it depends on connections like round-square [Read]
5. Theory of Logic / E. Structures of Logic / 8. Theories in Logic
A theory is logically closed, which means infinite premisses [Read]
5. Theory of Logic / G. Quantification / 1. Quantification
Quantifiers are second-order predicates [Read]
5. Theory of Logic / G. Quantification / 5. Second-Order Quantification
In second-order logic the higher-order variables range over all the properties of the objects [Read]
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
A logical truth is the conclusion of a valid inference with no premisses [Read]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
Any first-order theory of sets is inadequate [Read]
5. Theory of Logic / K. Features of Logics / 6. Compactness
Compactness does not deny that an inference can have infinitely many premisses [Read]
Compactness is when any consequence of infinite propositions is the consequence of a finite subset [Read]
Compactness blocks the proof of 'for every n, A(n)' (as the proof would be infinite) [Read]
Compactness makes consequence manageable, but restricts expressive power [Read]
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / a. The Liar paradox
Self-reference paradoxes seem to arise only when falsity is involved [Read]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / d. Actual infinite
Infinite cuts and successors seems to suggest an actual infinity there waiting for us [Read]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / e. Peano arithmetic 2nd-order
Although second-order arithmetic is incomplete, it can fully model normal arithmetic [Read]
Second-order arithmetic covers all properties, ensuring categoricity [Read]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / g. Von Neumann numbers
Von Neumann numbers are helpful, but don't correctly describe numbers [Read]
7. Existence / D. Theories of Reality / 10. Vagueness / d. Vagueness as linguistic
Would a language without vagueness be usable at all? [Read]
7. Existence / D. Theories of Reality / 10. Vagueness / f. Supervaluation for vagueness
Supervaluations say there is a cut-off somewhere, but at no particular place [Read]
A 'supervaluation' gives a proposition consistent truth-value for classical assignments [Read]
Identities and the Indiscernibility of Identicals don't work with supervaluations [Read]
9. Objects / A. Existence of Objects / 5. Individuation / d. Individuation by haecceity
A haecceity is a set of individual properties, essential to each thing [Read]
10. Modality / A. Necessity / 2. Nature of Necessity
Equating necessity with truth in every possible world is the S5 conception of necessity [Read]
10. Modality / B. Possibility / 8. Conditionals / a. Conditionals
The standard view of conditionals is that they are truth-functional [Read]
The point of conditionals is to show that one will accept modus ponens [Read]
Some people even claim that conditionals do not express propositions [Read]
10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds
Knowledge of possible worlds is not causal, but is an ontology entailed by semantics [Read]
10. Modality / E. Possible worlds / 1. Possible Worlds / c. Possible worlds realism
How can modal Platonists know the truth of a modal proposition? [Read]
10. Modality / E. Possible worlds / 1. Possible Worlds / d. Possible worlds actualism
Actualism is reductionist (to parts of actuality), or moderate realist (accepting real abstractions) [Read]
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / c. Worlds as propositions
A possible world is a determination of the truth-values of all propositions of a domain [Read]
10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts
If worlds are concrete, objects can't be present in more than one, and can only have counterparts [Read]
12. Knowledge Sources / D. Empiricism / 4. Pro-Empiricism
Events are baffling before experience, and obvious after experience [Hume]
15. Nature of Minds / C. Capacities of Minds / 3. Abstraction by mind
The mind abstracts ways things might be, which are nonetheless real [Read]
18. Thought / B. Mechanics of Thought / 5. Mental Files
There is a single file per object, memorised, reactivated, consolidated and expanded [Papineau, by Recanati]
19. Language / C. Assigning Meanings / 4. Compositionality
Negative existentials with compositionality make the whole sentence meaningless [Read]
19. Language / D. Propositions / 1. Propositions
A proposition objectifies what a sentence says, as indicative, with secure references [Read]
28. God / A. Divine Nature / 3. Divine Perfections
We can't assume God's perfections are like our ideas or like human attributes [Hume]
28. God / B. Proving God / 1. Proof of God
The objects of theological reasoning are too big for our minds [Hume]
28. God / B. Proving God / 2. Proofs of Reason / b. Ontological Proof critique
No being's non-existence can imply a contradiction, so its existence cannot be proved a priori [Hume]
28. God / B. Proving God / 3. Proofs of Evidence / a. Cosmological Proof
A chain of events requires a cause for the whole as well as the parts, yet the chain is just a sum of parts [Hume]
If something must be necessary so that something exists rather than nothing, why can't the universe be necessary? [Hume]
28. God / B. Proving God / 3. Proofs of Evidence / b. Teleological Proof
The thing which contains order must be God, so see God where you see order [Hume]
28. God / B. Proving God / 3. Proofs of Evidence / c. Teleological Proof critique
Analogy suggests that God has a very great human mind [Hume]
How can we pronounce on a whole after a brief look at a very small part? [Hume]
If the divine cause is proportional to its effects, the effects are finite, so the Deity cannot be infinite [Hume]
Design cannot prove a unified Deity. Many men make a city, so why not many gods for a world? [Hume]
From a ship you would judge its creator a genius, not a mere humble workman [Hume]
Creation is more like vegetation than human art, so it won't come from reason [Hume]
This excellent world may be the result of a huge sequence of trial-and-error [Hume]
Humans renew their species sexually. If there are many gods, would they not do the same? [Hume]
This Creator god might be an infant or incompetent or senile [Hume]
Order may come from an irrational source as well as a rational one [Hume]
Motion often begins in matter, with no sign of a controlling agent [Hume]
The universe could settle into superficial order, without a designer [Hume]
Ideas arise from objects, not vice versa; ideas only influence matter if they are linked [Hume]
A surprise feature of all products of 9 looks like design, but is actually a necessity [Hume]
The universe may be the result of trial-and-error [Hume]
From our limited view, we cannot tell if the universe is faulty [Hume]
Why would we infer an infinite creator from a finite creation? [Hume]