Combining Texts

All the ideas for 'Principles of Philosophy', 'First-order Logic, 2nd-order, Completeness' and 'Leibniz'

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34 ideas

1. Philosophy / D. Nature of Philosophy / 2. Invocation to Philosophy
The greatest good for a state is true philosophers [Descartes]
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]
8. Modes of Existence / C. Powers and Dispositions / 3. Powers as Derived
All powers can be explained by obvious features like size, shape and motion of matter [Descartes]
8. Modes of Existence / D. Universals / 1. Universals
Five universals: genus, species, difference, property, accident [Descartes]
8. Modes of Existence / E. Nominalism / 2. Resemblance Nominalism
A universal is a single idea applied to individual things that are similar to one another [Descartes]
9. Objects / B. Unity of Objects / 2. Substance / a. Substance
If we perceive an attribute, we infer the existence of some substance [Descartes]
9. Objects / B. Unity of Objects / 2. Substance / d. Substance defined
A substance needs nothing else in order to exist [Descartes]
9. Objects / D. Essence of Objects / 9. Essence and Properties
A substance has one principal property which is its nature and essence [Descartes]
9. Objects / F. Identity among Objects / 7. Indiscernible Objects
The Identity of Indiscernibles is really the same as the verification principle [Jolley]
11. Knowledge Aims / B. Certain Knowledge / 4. The Cogito
Total doubt can't include your existence while doubting [Descartes]
I think, therefore I am, because for a thinking thing to not exist is a contradiction [Descartes]
'Thought' is all our conscious awareness, including feeling as well as understanding [Descartes]
12. Knowledge Sources / A. A Priori Knowledge / 4. A Priori as Necessities
'Nothing comes from nothing' is an eternal truth found within the mind [Descartes]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / b. Basic beliefs
We can know basic Principles without further knowledge, but not the other way round [Descartes]
15. Nature of Minds / B. Features of Minds / 1. Consciousness / b. Essence of consciousness
We can understand thinking occuring without imagination or sensation [Descartes]
16. Persons / D. Continuity of the Self / 7. Self and Thinking
In thinking we shut ourselves off from other substances, showing our identity and separateness [Descartes]
16. Persons / F. Free Will / 1. Nature of Free Will
Our free will is so self-evident to us that it must be a basic innate idea [Descartes]
17. Mind and Body / A. Mind-Body Dualism / 1. Dualism
There are two ultimate classes of existence: thinking substance and extended substance [Descartes]
17. Mind and Body / D. Property Dualism / 5. Supervenience of mind
Even if tightly united, mind and body are different, as God could separate them [Descartes]
18. Thought / A. Modes of Thought / 6. Judgement / b. Error
Most errors of judgement result from an inaccurate perception of the facts [Descartes]
20. Action / C. Motives for Action / 4. Responsibility for Actions
We do not praise the acts of an efficient automaton, as their acts are necessary [Descartes]
The greatest perfection of man is to act by free will, and thus merit praise or blame [Descartes]
26. Natural Theory / A. Speculations on Nature / 1. Nature
Physics only needs geometry or abstract mathematics, which can explain and demonstrate everything [Descartes]
26. Natural Theory / A. Speculations on Nature / 2. Natural Purpose / c. Purpose denied
We will not try to understand natural or divine ends, or final causes [Descartes]
26. Natural Theory / A. Speculations on Nature / 7. Later Matter Theories / c. Matter as extension
Matter is not hard, heavy or coloured, but merely extended in space [Descartes]