Combining Texts

All the ideas for 'teaching', 'Logic in Mathematics' and 'The Work of a Free Person'

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32 ideas

1. Philosophy / A. Wisdom / 1. Nature of Wisdom
Speak the truth, for this alone deifies man [Pythagoras, by Porphyry]
1. Philosophy / B. History of Ideas / 2. Ancient Thought
Pythagoras discovered the numerical relation of sounds on a string [Pythagoras, by Diog. Laertius]
2. Reason / D. Definition / 3. Types of Definition
A 'constructive' (as opposed to 'analytic') definition creates a new sign [Frege]
2. Reason / D. Definition / 10. Stipulative Definition
Frege suggested that mathematics should only accept stipulative definitions [Frege, by Gupta]
2. Reason / E. Argument / 6. Conclusive Proof
We must be clear about every premise and every law used in a proof [Frege]
5. Theory of Logic / A. Overview of Logic / 3. Value of Logic
Logic not only proves things, but also reveals logical relations between them [Frege]
5. Theory of Logic / A. Overview of Logic / 8. Logic of Mathematics
Does some mathematical reasoning (such as mathematical induction) not belong to logic? [Frege]
The closest subject to logic is mathematics, which does little apart from drawing inferences [Frege]
5. Theory of Logic / E. Structures of Logic / 8. Theories in Logic
'Theorems' are both proved, and used in proofs [Frege]
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
Tracing inference backwards closes in on a small set of axioms and postulates [Frege]
The essence of mathematics is the kernel of primitive truths on which it rests [Frege]
Axioms are truths which cannot be doubted, and for which no proof is needed [Frege]
A truth can be an axiom in one system and not in another [Frege]
6. Mathematics / A. Nature of Mathematics / 1. Mathematics
To create order in mathematics we need a full system, guided by patterns of inference [Frege]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / m. One
For Pythagoreans 'one' is not a number, but the foundation of numbers [Pythagoras, by Watson]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / a. Axioms for numbers
If principles are provable, they are theorems; if not, they are axioms [Frege]
9. Objects / B. Unity of Objects / 3. Unity Problems / e. Vague objects
Every concept must have a sharp boundary; we cannot allow an indeterminate third case [Frege]
18. Thought / B. Mechanics of Thought / 5. Mental Files
We need definitions to cram retrievable sense into a signed receptacle [Frege]
We use signs to mark receptacles for complex senses [Frege]
19. Language / A. Nature of Meaning / 6. Meaning as Use
A sign won't gain sense just from being used in sentences with familiar components [Frege]
19. Language / D. Propositions / 2. Abstract Propositions / a. Propositions as sense
Thoughts are not subjective or psychological, because some thoughts are the same for us all [Frege]
A thought is the sense expressed by a sentence, and is what we prove [Frege]
19. Language / D. Propositions / 5. Unity of Propositions
The parts of a thought map onto the parts of a sentence [Frege]
22. Metaethics / B. Value / 2. Values / d. Health
Pythagoras taught that virtue is harmony, and health, and universal good, and God [Pythagoras, by Diog. Laertius]
23. Ethics / C. Virtue Theory / 3. Virtues / c. Justice
For Pythagoreans, justice is simply treating all people the same [Pythagoras, by Aristotle]
24. Political Theory / D. Ideologies / 11. Capitalism
Once money is the main aim, society needs everyone to think wealth is possible [Weil]
26. Natural Theory / A. Speculations on Nature / 4. Mathematical Nature
For Pythagoreans the entire universe is made of numbers [Pythagoras, by Aristotle]
Pythagoreans define timeliness, justice and marriage in terms of numbers [Pythagoras, by Aristotle]
Pythagoreans think mathematical principles are the principles of all of nature [Pythagoras, by Aristotle]
Pythagoreans say things imitate numbers, but Plato says things participate in numbers [Pythagoras, by Aristotle]
When musical harmony and rhythm were discovered, similar features were seen in bodily movement [Pythagoras, by Plato]
29. Religion / D. Religious Issues / 2. Immortality / a. Immortality
The modern idea of an immortal soul was largely created by Pythagoras [Pythagoras, by Watson]