Combining Texts

All the ideas for 'Wiener Logik', 'Alfred Tarski: life and logic' and 'On the Heavens'

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27 ideas

2. Reason / A. Nature of Reason / 9. Limits of Reason
19740 A very hungry man cannot choose between equidistant piles of food [Aristotle]
2. Reason / D. Definition / 2. Aims of Definition
18261 A simplification which is complete constitutes a definition [Kant]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
10147 The Axiom of Choice is consistent with the other axioms of set theory [Feferman/Feferman]
10148 Axiom of Choice: a set exists which chooses just one element each of any set of sets [Feferman/Feferman]
10149 Platonist will accept the Axiom of Choice, but others want criteria of selection or definition [Feferman/Feferman]
10150 The Trichotomy Principle is equivalent to the Axiom of Choice [Feferman/Feferman]
10146 Cantor's theories needed the Axiom of Choice, but it has led to great controversy [Feferman/Feferman]
5. Theory of Logic / A. Overview of Logic / 3. Value of Logic
22275 Logic gives us the necessary rules which show us how we ought to think [Kant]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
10158 A structure is a 'model' when the axioms are true. So which of the structures are models? [Feferman/Feferman]
10162 Tarski and Vaught established the equivalence relations between first-order structures [Feferman/Feferman]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
10159 Löwenheim-Skolem Theorem, and Gödel's completeness of first-order logic, the earliest model theory [Feferman/Feferman]
10160 Löwenheim-Skolem says if the sentences are countable, so is the model [Feferman/Feferman]
5. Theory of Logic / K. Features of Logics / 4. Completeness
10161 If a sentence holds in every model of a theory, then it is logically derivable from the theory [Feferman/Feferman]
5. Theory of Logic / K. Features of Logics / 7. Decidability
10156 'Recursion theory' concerns what can be solved by computing machines [Feferman/Feferman]
10155 Both Principia Mathematica and Peano Arithmetic are undecidable [Feferman/Feferman]
13. Knowledge Criteria / A. Justification Problems / 3. Internal or External / b. Pro-externalism
18260 If we knew what we know, we would be astonished [Kant]
22. Metaethics / B. Value / 2. Values / b. Successful function
398 Each thing that has a function is for the sake of that function [Aristotle]
26. Natural Theory / A. Speculations on Nature / 2. Natural Purpose / a. Final purpose
394 An unworn sandal is in vain, but nothing in nature is in vain [Aristotle]
396 There has to be some goal, and not just movement to infinity [Aristotle]
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / f. Ancient elements
16102 Aether moves in circles and is imperishable; the four elements perish, and move in straight lines [Aristotle, by Gill,ML]
17463 An element is what bodies are analysed into, and won't itself divide into something else [Aristotle]
27. Natural Reality / A. Classical Physics / 1. Mechanics / a. Explaining movement
399 If the more you raise some earth the faster it moves, why does the whole earth not move? [Aristotle]
27. Natural Reality / C. Space / 1. Void
20918 Void is a kind of place, so it can't explain place [Aristotle]
27. Natural Reality / E. Cosmology / 1. Cosmology
402 The Earth must be spherical, because it casts a convex shadow on the moon [Aristotle]
403 The earth must be round and of limited size, because moving north or south makes different stars visible [Aristotle]
27. Natural Reality / E. Cosmology / 3. The Beginning
1498 Everyone agrees that the world had a beginning, but thinkers disagree over whether it will end [Aristotle]
27. Natural Reality / E. Cosmology / 10. Multiverse
395 It seems possible that there exists a limited number of other worlds apart from this one [Aristotle]