Combining Texts

All the ideas for 'Aristotle and Descartes on Matter', 'First-order Logic, 2nd-order, Completeness' and 'Scientific Attitude and Fallibilism'

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19 ideas

5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
Second-order logic needs the sets, and its consequence has epistemological problems [Rossberg]
Henkin semantics has a second domain of predicates and relations (in upper case) [Rossberg]
There are at least seven possible systems of semantics for second-order logic [Rossberg]
5. Theory of Logic / B. Logical Consequence / 2. Types of Consequence
Logical consequence is intuitively semantic, and captured by model theory [Rossberg]
5. Theory of Logic / B. Logical Consequence / 3. Deductive Consequence |-
Γ |- S says S can be deduced from Γ; Γ |= S says a good model for Γ makes S true [Rossberg]
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
In proof-theory, logical form is shown by the logical constants [Rossberg]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
A model is a domain, and an interpretation assigning objects, predicates, relations etc. [Rossberg]
5. Theory of Logic / J. Model Theory in Logic / 2. Isomorphisms
If models of a mathematical theory are all isomorphic, it is 'categorical', with essentially one model [Rossberg]
5. Theory of Logic / K. Features of Logics / 4. Completeness
Completeness can always be achieved by cunning model-design [Rossberg]
5. Theory of Logic / K. Features of Logics / 5. Incompleteness
A deductive system is only incomplete with respect to a formal semantics [Rossberg]
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / c. Counting procedure
Numbers are just names devised for counting [Peirce]
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / c. Against mathematical empiricism
That two two-eyed people must have four eyes is a statement about numbers, not a fact [Peirce]
11. Knowledge Aims / B. Certain Knowledge / 3. Fallibilism
Reasoning is based on statistical induction, so it can't achieve certainty or precision [Peirce]
12. Knowledge Sources / A. A Priori Knowledge / 3. Innate Knowledge / a. Innate knowledge
Innate truths are very uncertain and full of error, so they certainly have exceptions [Peirce]
12. Knowledge Sources / E. Direct Knowledge / 3. Inspiration
A truth is hard for us to understand if it rests on nothing but inspiration [Peirce]
If we decide an idea is inspired, we still can't be sure we have got the idea right [Peirce]
Only reason can establish whether some deliverance of revelation really is inspired [Peirce]
15. Nature of Minds / C. Capacities of Minds / 2. Imagination
Only imagination can connect phenomena together in a rational way [Peirce]
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / b. Prime matter
Prime matter is nothing when it is at rest [Leibniz]