Combining Texts

All the ideas for 'Logical Consequence', 'On the Syllogism IV' and 'Essays on Intellectual Powers 5: Abstraction'

expand these ideas     |    start again     |     specify just one area for these texts

16 ideas

4. Formal Logic / A. Syllogistic Logic / 2. Syllogistic Logic
10688 'Equivocation' is when terms do not mean the same thing in premises and conclusion [Beall/Restall]
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
10690 Formal logic is invariant under permutations, or devoid of content, or gives the norms for thought [Beall/Restall]
5. Theory of Logic / B. Logical Consequence / 2. Types of Consequence
10691 Logical consequence needs either proofs, or absence of counterexamples [Beall/Restall]
5. Theory of Logic / B. Logical Consequence / 4. Semantic Consequence |=
10695 Logical consequence is either necessary truth preservation, or preservation based on interpretation [Beall/Restall]
5. Theory of Logic / B. Logical Consequence / 8. Material Implication
10689 A step is a 'material consequence' if we need contents as well as form [Beall/Restall]
5. Theory of Logic / E. Structures of Logic / 6. Relations in Logic
17744 De Morgan started the study of relations and their properties [De Morgan, by Walicki]
13501 De Morgan found inferences involving relations, which eluded Aristotle's syllogistic [De Morgan, by Hart,WD]
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
10696 A 'logical truth' (or 'tautology', or 'theorem') follows from empty premises [Beall/Restall]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
10693 Models are mathematical structures which interpret the non-logical primitives [Beall/Restall]
6. Mathematics / B. Foundations for Mathematics / 2. Proof in Mathematics
10692 Hilbert proofs have simple rules and complex axioms, and natural deduction is the opposite [Beall/Restall]
8. Modes of Existence / D. Universals / 5. Universals as Concepts
23651 Universals are not objects of sense and cannot be imagined - but can be conceived [Reid]
8. Modes of Existence / E. Nominalism / 1. Nominalism / b. Nominalism about universals
23650 Only individuals exist [Reid]
8. Modes of Existence / E. Nominalism / 2. Resemblance Nominalism
23649 No one thinks two sheets possess a single whiteness, but all agree they are both white [Reid]
9. Objects / F. Identity among Objects / 1. Concept of Identity
11874 Real identity admits of no degrees [Reid]
18. Thought / A. Modes of Thought / 1. Thought
23652 We must first conceive things before we can consider them [Reid]
18. Thought / E. Abstraction / 1. Abstract Thought
23648 First we notice and name attributes ('abstracting'); then we notice that subjects share them ('generalising') [Reid]