Combining Philosophers

All the ideas for Hermarchus, Paul Boghossian and Graham Priest

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52 ideas

2. Reason / B. Laws of Thought / 3. Non-Contradiction
Someone standing in a doorway seems to be both in and not-in the room [Priest,G, by Sorensen]
2. Reason / D. Definition / 4. Real Definition
A sentence may simultaneously define a term, and also assert a fact [Boghossian]
3. Truth / H. Deflationary Truth / 3. Minimalist Truth
Minimalism is incoherent, as it implies that truth both is and is not a property [Boghossian, by Horwich]
4. Formal Logic / E. Nonclassical Logics / 5. Relevant Logic
A logic is 'relevant' if premise and conclusion are connected, and 'paraconsistent' allows contradictions [Priest,G, by Friend]
4. Formal Logic / E. Nonclassical Logics / 6. Free Logic
Free logic is one of the few first-order non-classical logics [Priest,G]
4. Formal Logic / F. Set Theory ST / 2. Mechanics of Set Theory / a. Symbols of ST
X1 x X2 x X3... x Xn indicates the 'cartesian product' of those sets [Priest,G]
<a,b&62; is a set whose members occur in the order shown [Priest,G]
{x; A(x)} is a set of objects satisfying the condition A(x) [Priest,G]
{a1, a2, ...an} indicates that a set comprising just those objects [Priest,G]
a ∈ X says a is an object in set X; a ∉ X says a is not in X [Priest,G]
Φ indicates the empty set, which has no members [Priest,G]
{a} is the 'singleton' set of a (not the object a itself) [Priest,G]
X⊆Y means set X is a 'subset' of set Y [Priest,G]
X⊂Y means set X is a 'proper subset' of set Y [Priest,G]
X = Y means the set X equals the set Y [Priest,G]
X ∩ Y indicates the 'intersection' of sets X and Y, the objects which are in both sets [Priest,G]
Y - X is the 'relative complement' of X with respect to Y; the things in Y that are not in X [Priest,G]
X∪Y indicates the 'union' of all the things in sets X and Y [Priest,G]
4. Formal Logic / F. Set Theory ST / 2. Mechanics of Set Theory / b. Terminology of ST
The 'union' of two sets is a set containing all the things in either of the sets [Priest,G]
The 'intersection' of two sets is a set of the things that are in both sets [Priest,G]
The 'relative complement' is things in the second set not in the first [Priest,G]
The 'induction clause' says complex formulas retain the properties of their basic formulas [Priest,G]
A 'cartesian product' of sets is the set of all the n-tuples with one member in each of the sets [Priest,G]
A 'set' is a collection of objects [Priest,G]
A 'member' of a set is one of the objects in the set [Priest,G]
An 'ordered pair' (or ordered n-tuple) is a set with its members in a particular order [Priest,G]
A 'singleton' is a set with only one member [Priest,G]
The 'empty set' or 'null set' has no members [Priest,G]
A set is a 'subset' of another set if all of its members are in that set [Priest,G]
A 'proper subset' is smaller than the containing set [Priest,G]
4. Formal Logic / F. Set Theory ST / 2. Mechanics of Set Theory / c. Basic theorems of ST
The empty set Φ is a subset of every set (including itself) [Priest,G]
5. Theory of Logic / I. Semantics of Logic / 2. Formal Truth
Conventionalism agrees with realists that logic has truth values, but not over the source [Boghossian]
5. Theory of Logic / L. Paradox / 1. Paradox
Typically, paradoxes are dealt with by dividing them into two groups, but the division is wrong [Priest,G]
5. Theory of Logic / L. Paradox / 4. Paradoxes in Logic / b. König's paradox
The 'least indefinable ordinal' is defined by that very phrase [Priest,G]
5. Theory of Logic / L. Paradox / 4. Paradoxes in Logic / c. Berry's paradox
'x is a natural number definable in less than 19 words' leads to contradiction [Priest,G]
5. Theory of Logic / L. Paradox / 4. Paradoxes in Logic / d. Richard's paradox
By diagonalization we can define a real number that isn't in the definable set of reals [Priest,G]
5. Theory of Logic / L. Paradox / 5. Paradoxes in Set Theory / c. Burali-Forti's paradox
The least ordinal greater than the set of all ordinals is both one of them and not one of them [Priest,G]
5. Theory of Logic / L. Paradox / 5. Paradoxes in Set Theory / e. Mirimanoff's paradox
The next set up in the hierarchy of sets seems to be both a member and not a member of it [Priest,G]
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / a. The Liar paradox
There are Liar Pairs, and Liar Chains, which fit the same pattern as the basic Liar [Priest,G]
If you know that a sentence is not one of the known sentences, you know its truth [Priest,G]
12. Knowledge Sources / A. A Priori Knowledge / 4. A Priori as Necessities
'Snow is white or it isn't' is just true, not made true by stipulation [Boghossian]
12. Knowledge Sources / A. A Priori Knowledge / 8. A Priori as Analytic
The a priori is explained as analytic to avoid a dubious faculty of intuition [Boghossian]
That logic is a priori because it is analytic resulted from explaining the meaning of logical constants [Boghossian]
We can't hold a sentence true without evidence if we can't agree which sentence is definitive of it [Boghossian]
12. Knowledge Sources / A. A Priori Knowledge / 11. Denying the A Priori
We may have strong a priori beliefs which we pragmatically drop from our best theory [Boghossian]
12. Knowledge Sources / E. Direct Knowledge / 2. Intuition
If we learn geometry by intuition, how could this faculty have misled us for so long? [Boghossian]
19. Language / A. Nature of Meaning / 7. Meaning Holism / c. Meaning by Role
'Conceptual role semantics' says terms have meaning from sentences and/or inferences [Boghossian]
If meaning depends on conceptual role, what properties are needed to do the job? [Boghossian]
19. Language / A. Nature of Meaning / 8. Synonymy
Could expressions have meaning, without two expressions possibly meaning the same? [Boghossian]
19. Language / E. Analyticity / 2. Analytic Truths
There are no truths in virtue of meaning, but there is knowability in virtue of understanding [Boghossian, by Jenkins]
19. Language / E. Analyticity / 3. Analytic and Synthetic
Epistemological analyticity: grasp of meaning is justification; metaphysical: truth depends on meaning [Boghossian]
25. Social Practice / F. Life Issues / 6. Animal Rights
Animals are dangerous and nourishing, and can't form contracts of justice [Hermarchus, by Sedley]