Combining Texts

All the ideas for 'General Facts,Phys Necessity, and Metaph of Time', 'Higher-Order Logic' and 'The Sophist'

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29 ideas

1. Philosophy / D. Nature of Philosophy / 2. Invocation to Philosophy
We must fight fiercely for knowledge, understanding and intelligence [Plato]
1. Philosophy / F. Analytic Philosophy / 7. Limitations of Analysis
The desire to split everything into its parts is unpleasant and unphilosophical [Plato]
2. Reason / C. Styles of Reason / 1. Dialectic
Good analysis involves dividing things into appropriate forms without confusion [Plato]
Dialectic should only be taught to those who already philosophise well [Plato]
2. Reason / C. Styles of Reason / 2. Elenchus
In discussion a person's opinions are shown to be in conflict, leading to calm self-criticism [Plato]
3. Truth / B. Truthmakers / 3. Truthmaker Maximalism
The truth-maker principle is that every truth has a sufficient truth-maker [Forrest]
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 / 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
Up Löwenheim-Skolem: if natural numbers satisfy wffs, then an infinite domain satisfies them [Shapiro]
The Löwenheim-Skolem Theorems fail for second-order languages with standard semantics [Shapiro]
The Löwenheim-Skolem theorem seems to be a defect of first-order logic [Shapiro]
Downward Löwenheim-Skolem: if there's an infinite model, there is a countable model [Shapiro]
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]
7. Existence / A. Nature of Existence / 3. Being / d. Non-being
What does 'that which is not' refer to? [Plato]
7. Existence / A. Nature of Existence / 3. Being / e. Being and nothing
If statements about non-existence are logically puzzling, so are statements about existence [Plato]
7. Existence / A. Nature of Existence / 6. Criterion for Existence
To be is to have a capacity, to act on other things, or to receive actions [Plato]
7. Existence / D. Theories of Reality / 6. Physicalism
Some alarming thinkers think that only things which you can touch exist [Plato]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / a. Ontological commitment
Whenever there's speech it has to be about something [Plato]
8. Modes of Existence / B. Properties / 11. Properties as Sets
Logicians use 'property' and 'set' interchangeably, with little hanging on it [Shapiro]
8. Modes of Existence / D. Universals / 6. Platonic Forms / a. Platonic Forms
Good thinkers spot forms spread through things, or included within some larger form [Plato]
The not-beautiful is part of the beautiful, though opposed to it, and is just as real [Plato]
9. Objects / A. Existence of Objects / 6. Nihilism about Objects
If we see everything as separate, we can then give no account of it [Plato]
12. Knowledge Sources / C. Rationalism / 1. Rationalism
A soul without understanding is ugly [Plato]
23. Ethics / A. Egoism / 1. Ethical Egoism
Wickedness is an illness of the soul [Plato]
25. Social Practice / E. Policies / 5. Education / c. Teaching
Didactic education is hard work and achieves little [Plato]