Combining Philosophers

All the ideas for David Fair, Michal Walicki and John Duns Scotus

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45 ideas

4. Formal Logic / B. Propositional Logic PL / 1. Propositional Logic
Post proved the consistency of propositional logic in 1921 [Walicki]
Propositional language can only relate statements as the same or as different [Walicki]
4. Formal Logic / B. Propositional Logic PL / 3. Truth Tables
Boolean connectives are interpreted as functions on the set {1,0} [Walicki]
4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set
The empty set is useful for defining sets by properties, when the members are not yet known [Walicki]
The empty set avoids having to take special precautions in case members vanish [Walicki]
4. Formal Logic / F. Set Theory ST / 6. Ordering in Sets
Ordinals play the central role in set theory, providing the model of well-ordering [Walicki]
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
To determine the patterns in logic, one must identify its 'building blocks' [Walicki]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
A 'model' of a theory specifies interpreting a language in a domain to make all theorems true [Walicki]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
The L-S Theorem says no theory (even of reals) says more than a natural number theory [Walicki]
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
A compact axiomatisation makes it possible to understand a field as a whole [Walicki]
Axiomatic systems are purely syntactic, and do not presuppose any interpretation [Walicki]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
Ordinals are transitive sets of transitive sets; or transitive sets totally ordered by inclusion [Walicki]
Ordinals are the empty set, union with the singleton, and any arbitrary union of ordinals [Walicki]
The union of finite ordinals is the first 'limit ordinal'; 2ω is the second... [Walicki]
Two infinite ordinals can represent a single infinite cardinal [Walicki]
Members of ordinals are ordinals, and also subsets of ordinals [Walicki]
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
In non-Euclidean geometry, all Euclidean theorems are valid that avoid the fifth postulate [Walicki]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / f. Mathematical induction
Inductive proof depends on the choice of the ordering [Walicki]
7. Existence / A. Nature of Existence / 3. Being / a. Nature of Being
The concept of being has only one meaning, whether talking of universals or of God [Duns Scotus, by Dumont]
Being (not sensation or God) is the primary object of the intellect [Duns Scotus, by Dumont]
7. Existence / A. Nature of Existence / 6. Criterion for Existence
Are things distinct if they are both separate, or if only one of them can be separate? [Duns Scotus, by Pasnau]
8. Modes of Existence / B. Properties / 1. Nature of Properties
Accidents must have formal being, if they are principles of real action, and of mental action and thought [Duns Scotus]
8. Modes of Existence / D. Universals / 4. Uninstantiated Universals
Duns Scotus was a realist about universals [Duns Scotus, by Dumont]
8. Modes of Existence / E. Nominalism / 1. Nominalism / a. Nominalism
If only the singular exists, science is impossible, as that relies on true generalities [Duns Scotus, by Panaccio]
If things were singular they would only differ numerically, but horse and tulip differ more than that [Duns Scotus, by Panaccio]
9. Objects / A. Existence of Objects / 5. Individuation / a. Individuation
We distinguish one thing from another by contradiction, because this is, and that is not [Duns Scotus]
9. Objects / A. Existence of Objects / 5. Individuation / d. Individuation by haecceity
Scotus said a substantial principle of individuation [haecceitas] was needed for an essence [Duns Scotus, by Dumont]
The haecceity is the featureless thing which gives ultimate individuality to a substance [Duns Scotus, by Cover/O'Leary-Hawthorne]
9. Objects / B. Unity of Objects / 1. Unifying an Object / a. Intrinsic unification
'Unity' is a particularly difficult word, because things can have hidden unity [Duns Scotus]
9. Objects / B. Unity of Objects / 1. Unifying an Object / b. Unifying aggregates
It is absurd that there is no difference between a genuinely unified thing, and a mere aggregate [Duns Scotus]
9. Objects / B. Unity of Objects / 2. Substance / a. Substance
Substance is an intrinsic thing, so parts of substances can't also be intrinsic things [Duns Scotus]
Substance is only grasped under the general heading of 'being' [Duns Scotus]
9. Objects / C. Structure of Objects / 2. Hylomorphism / d. Form as unifier
Matter and form give true unity; subject and accident is just unity 'per accidens' [Duns Scotus]
9. Objects / C. Structure of Objects / 8. Parts of Objects / c. Wholes from parts
What prevents a stone from being divided into parts which are still the stone? [Duns Scotus]
9. Objects / D. Essence of Objects / 2. Types of Essence
Avicenna and Duns Scotus say essences have independent and prior existence [Duns Scotus, by Dumont]
9. Objects / F. Identity among Objects / 8. Leibniz's Law
Two things are different if something is true of one and not of the other [Duns Scotus]
10. Modality / A. Necessity / 2. Nature of Necessity
Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki]
11. Knowledge Aims / B. Certain Knowledge / 1. Certainty
Certainty comes from the self-evident, from induction, and from self-awareness [Duns Scotus, by Dumont]
11. Knowledge Aims / C. Knowing Reality / 1. Perceptual Realism / b. Direct realism
Scotus defended direct 'intuitive cognition', against the abstractive view [Duns Scotus, by Dumont]
12. Knowledge Sources / A. A Priori Knowledge / 2. Self-Evidence
Augustine's 'illumination' theory of knowledge leads to nothing but scepticism [Duns Scotus, by Dumont]
16. Persons / F. Free Will / 2. Sources of Free Will
The will retains its power for opposites, even when it is acting [Duns Scotus, by Dumont]
26. Natural Theory / C. Causation / 4. Naturalised causation
Science has shown that causal relations are just transfers of energy or momentum [Fair, by Sosa/Tooley]
Fair shifted his view to talk of counterfactuals about energy flow [Fair, by Schaffer,J]
28. God / A. Divine Nature / 2. Divine Nature
The concept of God is the unique first efficient cause, final cause, and most eminent being [Duns Scotus, by Dumont]
28. God / B. Proving God / 3. Proofs of Evidence / a. Cosmological Proof
We can't infer the infinity of God from creation ex nihilo [Duns Scotus, by Dumont]