Combining Texts

All the ideas for 'fragments/reports', 'De Re and De Dicto' and 'Higher-Order Logic'

expand these ideas     |    start again     |     specify just one area for these texts


22 ideas

4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
The axiom of choice is controversial, but it could be replaced [Shapiro]
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
First-order logic is Complete, and Compact, with the Löwenheim-Skolem Theorems [Shapiro]
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
Some say that second-order logic is mathematics, not logic [Shapiro]
If the aim of logic is to codify inferences, second-order logic is useless [Shapiro]
5. Theory of Logic / B. Logical Consequence / 1. Logical Consequence
Logical consequence can be defined in terms of the logical terminology [Shapiro]
5. Theory of Logic / F. Referring in Logic / 1. Naming / a. Names
Maybe proper names involve essentialism [Plantinga]
5. Theory of Logic / G. Quantification / 5. Second-Order Quantification
Second-order variables also range over properties, sets, relations or functions [Shapiro]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
The Löwenheim-Skolem theorem seems to be a defect of first-order logic [Shapiro]
Up Löwenheim-Skolem: if natural numbers satisfy wffs, then an infinite domain satisfies them [Shapiro]
Downward Löwenheim-Skolem: if there's an infinite model, there is a countable model [Shapiro]
The Löwenheim-Skolem Theorems fail for second-order languages with standard semantics [Shapiro]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / g. Real numbers
Could I name all of the real numbers in one fell swoop? Call them all 'Charley'? [Plantinga]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / e. Peano arithmetic 2nd-order
Second-order logic has the expressive power for mathematics, but an unworkable model theory [Shapiro]
8. Modes of Existence / B. Properties / 11. Properties as Sets
Logicians use 'property' and 'set' interchangeably, with little hanging on it [Shapiro]
9. Objects / A. Existence of Objects / 5. Individuation / d. Individuation by haecceity
Surely self-identity is essential to Socrates? [Plantinga]
9. Objects / D. Essence of Objects / 9. Essence and Properties
An object has a property essentially if it couldn't conceivably have lacked it [Plantinga]
10. Modality / A. Necessity / 4. De re / De dicto modality
Can we find an appropriate 'de dicto' paraphrase for any 'de re' proposition? [Plantinga]
Expressing modality about a statement is 'de dicto'; expressing it of property-possession is 'de re' [Plantinga]
'De dicto' true and 'de re' false is possible, and so is 'de dicto' false and 'de re' true [Plantinga]
10. Modality / E. Possible worlds / 3. Transworld Objects / a. Transworld identity
What Socrates could have been, and could have become, are different? [Plantinga]
26. Natural Theory / A. Speculations on Nature / 5. Infinite in Nature
Archelaus was the first person to say that the universe is boundless [Archelaus, by Diog. Laertius]
27. Natural Reality / G. Biology / 3. Evolution
Archelaus said life began in a primeval slime [Archelaus, by Schofield]