Combining Philosophers

All the ideas for Mark Sainsbury, Posidonius and George Boole

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17 ideas

4. Formal Logic / B. Propositional Logic PL / 1. Propositional Logic
Boole applied normal algebra to logic, aiming at an algebra of thought [Boole, by Devlin]
Boole's notation can represent syllogisms and propositional arguments, but not both at once [Boole, by Weiner]
5. Theory of Logic / A. Overview of Logic / 2. History of Logic
Boole made logic more mathematical, with algebra, quantifiers and probability [Boole, by Friend]
5. Theory of Logic / F. Referring in Logic / 1. Naming / e. Empty names
It is best to say that a name designates iff there is something for it to designate [Sainsbury]
5. Theory of Logic / F. Referring in Logic / 2. Descriptions / b. Definite descriptions
Definite descriptions may not be referring expressions, since they can fail to refer [Sainsbury]
Definite descriptions are usually rigid in subject, but not in predicate, position [Sainsbury]
5. Theory of Logic / H. Proof Systems / 2. Axiomatic Proof
Boole's method was axiomatic, achieving economy, plus multiple interpretations [Boole, by Potter]
7. Existence / D. Theories of Reality / 10. Vagueness / b. Vagueness of reality
If 'red' is vague, then membership of the set of red things is vague, so there is no set of red things [Sainsbury]
7. Existence / E. Categories / 2. Categorisation
We should abandon classifying by pigeon-holes, and classify around paradigms [Sainsbury]
9. Objects / B. Unity of Objects / 3. Unity Problems / e. Vague objects
Vague concepts are concepts without boundaries [Sainsbury]
If concepts are vague, people avoid boundaries, can't spot them, and don't want them [Sainsbury]
Boundaryless concepts tend to come in pairs, such as child/adult, hot/cold [Sainsbury]
19. Language / B. Reference / 3. Direct Reference / b. Causal reference
A new usage of a name could arise from a mistaken baptism of nothing [Sainsbury]
19. Language / B. Reference / 5. Speaker's Reference
Even a quantifier like 'someone' can be used referentially [Sainsbury]
25. Social Practice / E. Policies / 5. Education / b. Education principles
Learned men gain more in one day than others do in a lifetime [Posidonius]
26. Natural Theory / A. Speculations on Nature / 3. Natural Function
Things are thought to have a function, even when they can't perform them [Sainsbury]
27. Natural Reality / D. Time / 1. Nature of Time / d. Time as measure
Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus]