Combining Philosophers

All the ideas for Herodotus, George Santayana and Marcus Rossberg

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

---

14 ideas

1. Philosophy / C. History of Philosophy / 1. History of Philosophy

8000	He who is ignorant of the history of philosophy is doomed to repeat it [Santayana, by MacIntyre]

5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic

10757

Henkin semantics has a second domain of predicates and relations (in upper case) [Rossberg]

10751

Second-order logic needs the sets, and its consequence has epistemological problems [Rossberg]

10759

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

10753

Logical consequence is intuitively semantic, and captured by model theory [Rossberg]

5. Theory of Logic / B. Logical Consequence / 3. Deductive Consequence |-

10752

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

10754

In proof-theory, logical form is shown by the logical constants [Rossberg]

5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models

10756

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

10758

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

10761

Completeness can always be achieved by cunning model-design [Rossberg]

5. Theory of Logic / K. Features of Logics / 5. Incompleteness

10755

A deductive system is only incomplete with respect to a formal semantics [Rossberg]

7. Existence / A. Nature of Existence / 6. Criterion for Existence

18521

The criterion of existence is the possibility of action [Santayana]

22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / e. Human nature

23060

The good is not relative, but is rooted in facts about human needs [Santayana]

29. Religion / D. Religious Issues / 2. Immortality / a. Immortality

1513	The Egyptians were the first to say the soul is immortal and reincarnated [Herodotus]