Combining Texts

All the ideas for 'Nominalism', 'Logical Necessity' and 'The Nature of Mathematics'

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23 ideas

1. Philosophy / G. Scientific Philosophy / 3. Scientism
14782 Philosophy is an experimental science, resting on common experience [Peirce]
2. Reason / B. Laws of Thought / 3. Non-Contradiction
14787 Self-contradiction doesn't reveal impossibility; it is inductive impossibility which reveals self-contradiction [Peirce]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / h. System S5
12204 The logic of metaphysical necessity is S5 [Rumfitt]
4. Formal Logic / F. Set Theory ST / 3. Types of Set / c. Unit (Singleton) Sets
8956 What is a singleton set, if a set is meant to be a collection of objects? [Szabó]
5. Theory of Logic / B. Logical Consequence / 1. Logical Consequence
12195 Soundness in argument varies with context, and may be achieved very informally indeed [Rumfitt]
12199 There is a modal element in consequence, in assessing reasoning from suppositions [Rumfitt]
12201 We reject deductions by bad consequence, so logical consequence can't be deduction [Rumfitt]
5. Theory of Logic / C. Ontology of Logic / 3. If-Thenism
14783 Logic, unlike mathematics, is not hypothetical; it asserts categorical ends from hypothetical means [Peirce]
5. Theory of Logic / D. Assumptions for Logic / 3. Contradiction
12194 Contradictions include 'This is red and not coloured', as well as the formal 'B and not-B' [Rumfitt]
5. Theory of Logic / H. Proof Systems / 2. Axiomatic Proof
12198 Geometrical axioms in logic are nowadays replaced by inference rules (which imply the logical truths) [Rumfitt]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / a. Early logicism
14788 Mathematics is close to logic, but is even more abstract [Peirce]
7. Existence / C. Structure of Existence / 7. Abstract/Concrete / a. Abstract/concrete
8953 Abstract entities don't depend on their concrete entities ...but maybe on the totality of concrete things [Szabó]
10. Modality / A. Necessity / 3. Types of Necessity
14532 A distinctive type of necessity is found in logical consequence [Rumfitt, by Hale/Hoffmann,A]
10. Modality / A. Necessity / 6. Logical Necessity
12193 Logical necessity is when 'necessarily A' implies 'not-A is contradictory' [Rumfitt]
12200 A logically necessary statement need not be a priori, as it could be unknowable [Rumfitt]
12202 Narrow non-modal logical necessity may be metaphysical, but real logical necessity is not [Rumfitt]
10. Modality / B. Possibility / 1. Possibility
14786 Some logical possibility concerns single propositions, but there is also compatibility between propositions [Peirce]
10. Modality / E. Possible worlds / 1. Possible Worlds / e. Against possible worlds
12203 If a world is a fully determinate way things could have been, can anyone consider such a thing? [Rumfitt]
12. Knowledge Sources / D. Empiricism / 1. Empiricism
14789 Experience is indeed our only source of knowledge, provided we include inner experience [Peirce]
12. Knowledge Sources / D. Empiricism / 5. Empiricism Critique
14785 The world is one of experience, but experiences are always located among our ideas [Peirce]
15. Nature of Minds / C. Capacities of Minds / 3. Abstraction by mind
8954 Geometrical circles cannot identify a circular paint patch, presumably because they lack something [Szabó]
18. Thought / E. Abstraction / 5. Abstracta by Negation
8955 Abstractions are imperceptible, non-causal, and non-spatiotemporal (the third explaining the others) [Szabó]
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / b. Defining ethics
14784 Ethics is the science of aims [Peirce]