Combining Texts

All the ideas for 'Necessary Existents', 'Elements of Geometry' and 'Change in View: Principles of Reasoning'

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23 ideas

2. Reason / A. Nature of Reason / 1. On Reason
It is a principle of reasoning not to clutter your mind with trivialities [Harman]
The rules of reasoning are not the rules of logic [Harman]
If there is a great cost to avoiding inconsistency, we learn to reason our way around it [Harman]
Logic has little relevance to reasoning, except when logical conclusions are immediate [Harman]
2. Reason / A. Nature of Reason / 4. Aims of Reason
Implication just accumulates conclusions, but inference may also revise our views [Harman]
2. Reason / E. Argument / 6. Conclusive Proof
Proof reveals the interdependence of truths, as well as showing their certainty [Euclid, by Frege]
4. Formal Logic / C. Predicate Calculus PC / 2. Tools of Predicate Calculus / c. Derivations rules of PC
If you pick an arbitrary triangle, things proved of it are true of all triangles [Euclid, by Lemmon]
6. Mathematics / A. Nature of Mathematics / 2. Geometry
Euclid's geometry is synthetic, but Descartes produced an analytic version of it [Euclid, by Resnik]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / b. Types of number
An assumption that there is a largest prime leads to a contradiction [Euclid, by Brown,JR]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / m. One
A unit is that according to which each existing thing is said to be one [Euclid]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / a. The Infinite
Postulate 2 says a line can be extended continuously [Euclid, by Shapiro]
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
Euclid relied on obvious properties in diagrams, as well as on his axioms [Potter on Euclid]
Euclid's parallel postulate defines unique non-intersecting parallel lines [Euclid, by Friend]
Euclid needs a principle of continuity, saying some lines must intersect [Shapiro on Euclid]
Euclid says we can 'join' two points, but Hilbert says the straight line 'exists' [Euclid, by Bernays]
Modern geometries only accept various parts of the Euclid propositions [Russell on Euclid]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / b. Greek arithmetic
Euclid's common notions or axioms are what we must have if we are to learn anything at all [Euclid, by Roochnik]
10. Modality / B. Possibility / 6. Probability
The Gambler's Fallacy (ten blacks, so red is due) overemphasises the early part of a sequence [Harman]
High probability premises need not imply high probability conclusions [Harman]
11. Knowledge Aims / A. Knowledge / 4. Belief / c. Aim of beliefs
We strongly desire to believe what is true, even though logic does not require it [Harman]
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / a. Coherence as justification
In revision of belief, we need to keep track of justifications for foundations, but not for coherence [Harman]
Coherence is intelligible connections, especially one element explaining another [Harman]
19. Language / D. Propositions / 3. Concrete Propositions
Propositions (such as 'that dog is barking') only exist if their items exist [Williamson]