This document discusses an alternative approach to logic called the logic of acceptance and rejection (AR4). It begins by outlining three views on logic: logical absolutism, relativism, and relative charity. It then introduces AR4, which treats logic as involving questions, answers, and speech acts of assertion and rejection. Under AR4, a proposition can be answered by either asserting or rejecting it in response to the questions of whether it is the case and whether it is not the case. This moves beyond the traditional view of logic as only involving truth. The document outlines the components of AR4 and how it represents logic using a four-valued semantics involving acceptance and rejection.
1. Relative Charity
(a1(p) = 1 a1(p) = 0)?
Fabien Schang
schang.fabien@voila.fr
fschang@hse.ru
National Research University, HSE
Seminar “Formal Philosophy”
24 February 2015
2. Content
1 The Background: Logic in Translation
2 An Alternative Referential Semantics
3 A Logic of Acceptance and Rejection
4 Coherence beyond Consistency
5 Truths in Meaning
6 Conclusion: The Answer is in the Question
7 Appendix: On Conditional
4. by reference to assent and dissent we can state semantic
criteria for truth-functions; i.e., criteria for determining
whether a given native idiom is to be constructed as
expressing the truth-function in question. The semantic
criterion of negation is that it turns any short sentence to
which one will assent into a sentence from which one will
dissent, and vice versa. That of conjunction is that it
produces compounds to which (so long as the component
sentences are short) one is prepared to assent always only
when one is prepared to assent to each component. That
of alternation is similar with assent changed twice to
dissent.
Quine (1960): 57-8
6. by reference to assent and dissent we can state semantic
criteria for truth-functions; i.e., criteria for determining
whether a given native idiom is to be constructed as
expressing the truth-function in question. The semantic
criterion of negation is that it turns any short sentence to
which one will assent into a sentence from which one will
dissent, and vice versa. That of conjunction is that it
produces compounds to which (so long as the component
sentences are short) one is prepared to assent always only
when one is prepared to assent to each component. That
of alternation is similar with assent changed twice to
dissent.
Quine (1960): 57-8
7. Negation
v(p) = T iff v(p) = F
Conjunction
v(p q) = T iff v(p) = v(q) = T
Disjunction
v(p q) = F iff v(p) = v(q) = F
… Conditional?
8. by reference to assent and dissent we can state semantic
criteria for truth-functions; i.e., criteria for determining
whether a given native idiom is to be constructed as
expressing the truth-function in question. The semantic
criterion of negation is that it turns any short sentence to
which one will assent into a sentence from which one will
dissent, and vice versa. That of conjunction is that it
produces compounds to which (so long as the component
sentences are short) one is prepared to assent always only
when one is prepared to assent to each component. That of
alternation is similar with assent changed twice to dissent.
Quine (1960): 57-8
9. Negation
v(p) = T iff v(p) = F
Conjunction
v(pq) = T iff v(p) = v(q) = T
Disjunction
v(p q) = F iff v(p) = v(q) = F
… Conditional?
10. by reference to assent and dissent we can state semantic
criteria for truth-functions; i.e., criteria for determining
whether a given native idiom is to be constructed as
expressing the truth-function in question. The semantic
criterion of negation is that it turns any short sentence to
which one will assent into a sentence from which one will
dissent, and vice versa. That of conjunction is that it
produces compounds to which (so long as the component
sentences are short) one is prepared to assent always only
when one is prepared to assent to each component. That of
alternation is similar with assent changed twice to dissent.
Quine (1960): 57-8
11. Negation
v(p) = T iff v(p) = F
Conjunction
v(pq) = T iff v(p) = v(q) = T
Disjunction
v(pq) = F iff v(p) = v(q) = F
12. Negation
v(p) = T iff v(p) = F
Conjunction
v(pq) = T iff v(p) = v(q) = T
Disjunction
v(pq) = F iff v(p) = v(q) = F
… Conditional?
13. The methodological advice to interpret in a way that
optimizes agreement should not be conceived as resting
on a charitable assumption about human intelligence that
might turn out to be false. If we cannot find a way to
interpret the utterances and other behavior of a creature
as revealing a set of beliefs largely consistent and true by
our own standards, we have no reason to count that
creature as rational, as having beliefs, or as saying
anything.
Davidson (1973): 324
15. (1) Logical Absolutism
A common rationality standard includes only one correct logic; there is
only one rational standard; therefore, there is only one correct logic.
(If A then B; A; therefore B)
(2) Logical Relativism
A common rationality standard includes only one correct logic; there are
several correct logics; therefore, there are several rational standards.
(If A then B; not-B; therefore A)
(3) Relative charity
A common rationality standard includes several correct logics
not-(if A then B) = A and not-B
16. (1) Logical Absolutism
A common rationality standard includes only one correct logic; there is
only one rational standard; therefore, there is only one correct logic.
(If A then B; A; therefore B)
(2) Logical Relativism
A common rationality standard includes only one correct logic; there are
several correct logics; therefore, there are several rational standards.
(If A then B; not-B; therefore not-A)
(3) Relative charity
A common rationality standard includes several correct logics
not-(if A then B) = A and not-B
17. (1) Logical Absolutism
A common rationality standard includes only one correct logic; there is
only one rational standard; therefore, there is only one correct logic.
(If A then B; A; therefore B)
(2) Logical Relativism
A common rationality standard includes only one correct logic; there are
several correct logics; therefore, there are several rational standards.
(If A then B; not-B; therefore not-A)
(3) Relative charity
A common rationality standard includes several correct logics
not-(if A then B) = A and not-B
18. Cultural anthropologists usually maintain that there is no
evidence that there exist cultures which adhere to
different logics than we do. But I find this a strange claim.
For one thing, even in my own country there is a
subculture of people who try to adhere to intuitionistic
logic rather than classical logic.
Lokhorst (1998): 57
19. The proper “Conceptual Scheme”: A Logic of Statements
- each lexicographer has to do with statements, rather than sentences
- statements: speech-acts performed with sentential content
Reference: Searle (1965)
p: sentence with truth-conditions (truth, false)
F(p): statement with satisfaction-conditions
F: assertion, order, declaration, … (speech-act theory)
In the following, 2 basic “transcendental” speech-acts:
- assertion (the speaker says “yes”, commits himself, accepts p)
- rejection (the speaker says “no”, does not commit himself, rejects p)
20. The proper “Conceptual Scheme”: A Logic of Statements
- each lexicographer has to do with statements, rather than sentences
- statements: speech-acts performed with sentential content
Reference: Searle (1965)
p: sentence with truth-conditions (truth, false)
F(p): statement with satisfaction-conditions
F: assertion, order, declaration, … (speech-act theory)
In the following, 2 basic “transcendental” speech-acts:
- assertion (the speaker says “yes”, commits himself, accepts p)
- rejection (the speaker says “no”, does not commit himself, rejects p)
21. The proper “Conceptual Scheme”: A Logic of Statements
- each lexicographer has to do with statements, rather than sentences
- statements: speech-acts performed with sentential content
Reference: Searle (1965)
p: sentence with truth-conditions (truth, false)
F(p): statement with satisfaction-conditions
F: assertion, order, declaration, … (speech-act theory)
In the following, 2 basic “transcendental” speech-acts:
- assertion (the speaker says “yes”, commits himself, accepts p)
- rejection (the speaker says “no”, does not commit himself, rejects p)
23. Meaning corresponds to a logical value:
a 3-dimensional object
answers = statements
A() = a11(), … ,aij() questions = sentences
parameters = quantifiers/modalities
24. AR4: Logic of Acceptance and Rejection (theory of normative answers)
2 main components:
Question Q: statement-forming operator upon a given sentence p
Q(p) = q1(p), …, qn(p)
The number of required questions about p is not predetermined
Answer A: set of ordered answers to a given question Q
A(p) = a1(p), …, am(p)
In AR4: n = 2 relevant questions, m = 2 possible sorts of answer
Card(V) = mn = 22 = 4
Note: n and m are independent from each other (rejectivism!)
25. AR4: Logic of Acceptance and Rejection (theory of normative answers)
2 main components:
Question Q: statement-forming operator upon a given sentence p
Q(p) = q1(p), …, qn(p)
The number of required questions about p is not predetermined
Answer A: set of ordered answers to a given question Q
A(p) = a1(p), …, am(p)
In AR4: n = 2 relevant questions, m = 2 possible sorts of answer
Card(V) = mn = 22 = 4
Note: n and m are independent from each other (rejectivism!)
26. AR4: Logic of Acceptance and Rejection (theory of normative answers)
2 main components:
Question Q: statement-forming operator upon a given sentence p
Q(p) = q1(p), …, qn(p)
The number of required questions about p is not predetermined
Answer A: set of ordered answers to a given question Q
A(p) = a1(p), …, am(p)
In AR4: n = 2 relevant questions, m = 2 possible sorts of answers
Card(V) = mn = 22 = 4
Note: n and m are independent from each other (rejectivism!)
27. AR4: Logic of Acceptance and Rejection (theory of normative answers)
2 main components:
Question Q: statement-forming operator upon a given sentence p
Q(p) = q1(p), …, qn(p)
The number of required questions about p is not predetermined
Answer A: set of ordered answers to a given question Q
A(p) = a1(p), …, am(p)
In AR4: n = 2 relevant questions, m = 2 possible sorts of answer
Card(V) = mn = 22 = 4
Note: n and m are independent from each other (rejectivism!)
28. Affirmation vs Negation (Question), Assertion vs Rejection (Answer)
Affirmation: expresses the sentence that p
Question: “Is it the case that p?” q1(p)
Negation: expresses the sentence opposed to p
Question: “Is it not the case that p?” = “Is it the case that not-p?”
q2(p) = q1(p)
Assertion: If I assert p, then I take p to be true (truth-claim)
Answer: “Yes, it is the case that p (is true)”
a1(p) = 1
Rejection: If I reject p, then I do not take p to be true (non-truth-claim)
Answer: “No, it is not the case that p (is true)”
a1(p) = 0
29. Affirmation vs Negation (Question), Assertion vs Rejection (Answer)
Affirmation: expresses the sentence that p
Question: “Is it the case that p?” q1(p)
Negation: expresses the sentence opposed to p
Question: “Is it not the case that p?” = “Is it the case that not-p?”
q2(p) = q1(p)
Assertion: If I assert p, then I take p to be true (truth-claim)
Answer: “Yes, it is the case that p (is true)”
a1(p) = 1
Rejection: If I reject p, then I do not take p to be true (non-truth-claim)
Answer: “No, it is not the case that p (is true)”
a1(p) = 0
30. Affirmation vs Negation (Question), Assertion vs Rejection (Answer)
Affirmation: expresses the sentence that p
Question: “Is it the case that p?” q1(p)
Negation: expresses the sentence opposed to p
Question: “Is it not the case that p?” = “Is it the case that not-p?”
q2(p) = q1(p)
Assertion: If I assert p, then I take p to be true (truth-claim)
Answer: “Yes, it is the case that p (is true)”
a1(p) = 1
Rejection: If I reject p, then I do not take p to be true (non-truth-claim)
Answer: “No, it is not the case that p (is true)”
a1(p) = 0
31. Affirmation vs Negation (Question), Assertion vs Rejection (Answer)
Affirmation: expresses the sentence that p
Question: “Is it the case that p?” q1(p)
Negation: expresses the sentence opposed to p
Question: “Is it not the case that p?” = “Is it the case that not-p?”
q2(p) = q1(p)
Assertion: If I assert p, then I take p to be true (truth-claim)
Answer: “Yes, it is the case that p (is true)”
a1(p) = 1
Rejection: If I reject p, then I do not take p to be true (non-truth-claim)
Answer: “No, it is not the case that p (is true)”
a1(p) = 0
32. Affirmation vs Negation (Question), Assertion vs Rejection (Answer)
Affirmation: expresses the sentence that p
Question: “Is it the case that p?” q1(p)
Negation: expresses the sentence opposed to p
Question: “Is it not the case that p?” = “Is it the case that not-p?”
q2(p) = q1(p)
Assertion: If I assert p, then I take p to be true (truth-claim)
Answer: “Yes, it is the case that p (is true)”
a1(p) = 1
Rejection: If I reject p, then I do not take p to be true (non-truth-claim)
Answer: “No, it is not the case that p (is true)”
a1(p) = 0
33. Unilateralism
Equivalence Thesis (Frege, 1919): there is no difference between
“No, it is not the case that p is true”
and
“Yes, it is the case that p is false”
a1(p) = 0 a2(p) = 1
Logical theory: a theory of truth-preservation, only
Denial is a by-product of assertion: a negative assertion
34. Unilateralism
Equivalence Thesis (Frege, 1919): there is no difference between
“No, it is not the case that p is true”
and
“Yes, it is the case that p is false”
a1(p) = 0 a2(p) = 1
Logical theory: a theory of truth-preservation, only
Denial is a by-product of assertion: a negative assertion
35. Unilateralism
Equivalence Thesis (Frege, 1919): there is no difference between
“No, it is not the case that p is true”
and
“Yes, it is the case that p is false”
a1(p) = 0 a2(p) = 1
Logical theory: a theory of truth-preservation, only
Denial is a by-product of assertion: a negative assertion
36. Correctness
Under what conditions can a sentence be correctly said to be “true”?
Correctness: assertibility-conditions
3 grades of “modal” involvement (3 modes of “being” true)
(1) strong correctness: true as impossibly false (truth “by default”)
(2) mild correctness: true as not false (truth “by default”)
(3) weak correctness: being true as being possibly not false
Frege assumed a mild view of truth: Bivalentism (Equivalence Thesis)
AR4: no involvement about what truth means (abstract logic)!
37. Correctness
Under what conditions can a sentence be correctly said to be “true”?
Correctness: assertibility-conditions
3 grades of “modal” involvement (3 modes of “being” true)
(1) strong correctness: true as impossibly false (truth “by default”)
(2) mild correctness: true as not false (truth “by default”)
(3) weak correctness: being true as being possibly not false
Frege assumed a mild view of truth: Bivalentism (Equivalence Thesis)
AR4: no involvement about what truth means (abstract logic)!
38. Correctness
Under what conditions can a sentence be correctly said to be “true”?
Correctness: assertibility-conditions
3 grades of “modal” involvement (3 modes of “being” true)
(1) strong correctness: true as impossibly false
(2) mild correctness: true as not false (truth “by default”)
(3) weak correctness: being true as being possibly not false
Frege assumed a mild view of truth: Bivalentism (Equivalence Thesis)
AR4: no involvement about what truth means (abstract logic)!
39. Correctness
Under what conditions can a sentence be correctly said to be “true”?
Correctness: assertibility-conditions
3 grades of “modal” involvement (3 modes of “being” true)
(1) strong correctness: true as impossibly false
(2) mild correctness: true as not false (truth “by default”)
(3) weak correctness: being true as being possibly not false
Frege assumed a mild view of truth: Bivalentism (Equivalence Thesis)
AR4: no involvement about what truth means (abstract logic)!
40. Correctness
Under what conditions can a sentence be correctly said to be “true”?
Correctness: assertibility-conditions
3 grades of “modal” involvement (3 modes of “being” true)
(1) strong correctness: true as impossibly false
(2) mild correctness: true as not false (truth “by default”)
(3) weak correctness: being true as being possibly not false
Frege assumed a mild view of truth: Bivalentism (Equivalence Thesis)
AR4: no involvement about what truth means (abstract logic)!
41. Correctness
Under what conditions can a sentence be correctly said to be “true”?
Correctness: assertibility-conditions
3 grades of “modal” involvement (3 modes of “being” true)
(1) strong correctness: true as impossibly false
(2) mild correctness: true as not false (truth “by default”)
(3) weak correctness: being true as being possibly not false
Frege assumed a mild view of truth: Bivalentism (Equivalence Thesis)
AR4: no involvement about what truth means (abstract logic)!
42. Logical constants: for every sentence p such that A(p) = a1(p),a2(p)
Negation
A(p) = a2(p),a1(p)
Conjunction
A(pq) = a1(p)a2(q),a2(p)a2(q)
Disjunction
A(pq) = a1(p)a2(q),a2(p)a2(q)
48. A Boolean translation of (non-)classical truth-values in AR4
v(p) = T
p is true only
A(p) = 1,0
v(p) = F
p is false only
A(p) = 0,1
v(p) = B
p is both true and false
A(p) = 1,1
v(p) = N
p is neither true nor false
A(p) = 0,0
49. A Boolean translation of (non-)classical truth-values in AR4
v(p) = T
p is true only
A(p) = 1,0
v(p) = F
p is false only
A(p) = 0,1
v(p) = B
p is both true and false
A(p) = 1,1
v(p) = N
p is neither true nor false
A(p) = 0,0
50. A Boolean translation of (non-)classical truth-values in AR4
v(p) = T
p is true only
A(p) = 1,0
v(p) = F
p is false only
A(p) = 0,1
v(p) = B
p is both true and false
A(p) = 1,1
v(p) = N
p is neither true nor false
A(p) = 0,0
51. A Boolean translation of (non-)classical truth-values in AR4
v(p) = T
p is true only
A(p) = 1,0
v(p) = F
p is false only
A(p) = 0,1
v(p) = B
p is both true and false
A(p) = 1,1
v(p) = N
p is neither true nor false
A(p) = 0,0
52. A Boolean translation of (non-)classical truth-values in AR4
v(p) = T
p is true only
A(p) = 1,0
v(p) = F
p is false only
A(p) = 0,1
v(p) = B
p is both true and false
A(p) = 1,1
v(p) = N
p is neither true nor false
A(p) = 0,0
54. 3 grades of belief inconsistency
(a) Bxp Bxp
(b) Bxp Bxp
(c) Bx(p Bxp)
2 norms of rationality
(CON) a1(p) = 1 a2(p) = 0
(COH) ai(p) = 1 ai(p) 0
What can “Yes and No” mean?
A bivalentist answerhood from a non-bivalentist perspective
“Yes” to p from one standpoint w1, “Yes” to p from another standpoint w2
(inconsistency)
“Yes” to p from w1, “No” to p to w1
(incoherence)
55. 3 grades of belief inconsistency
(a) Bxp Bxp
(b) Bxp Bxp
(c) Bx(p Bxp)
2 norms of rationality
(CON) a1(p) = 1 a2(p) = 0
(COH) ai(p) = 1 ai(p) 0
What can “Yes and No” mean?
A bivalentist answerhood from a non-bivalentist perspective
“Yes” to p from one standpoint w1, “Yes” to p from another standpoint w2
(inconsistency)
“Yes” to p from w1, “No” to p to w1
(incoherence)
56. 3 grades of belief inconsistency
(a) Bxp Bxp
(b) Bxp Bxp
(c) Bx(p Bxp)
2 norms of rationality
(CON) a1(p) = 1 a2(p) = 0
(COH) ai(p) = 1 ai(p) 0
What can “Yes and No” mean?
A bivalentist answerhood from a non-bivalentist perspective
“Yes” to p from one standpoint w1, “Yes” to p from another standpoint w2
(inconsistency)
“Yes” to p from w1, “No” to p to w1
(incoherence)
57. 3 grades of belief inconsistency
(a) Bxp Bxp
(b) Bxp Bxp
(c) Bx(p p)
2 norms of rationality
(CON) a1(p) = 1 a2(p) = 0
(COH) ai(p) = 1 ai(p) 0
What can “Yes and No” mean?
A bivalentist answerhood from a non-bivalentist perspective
“Yes” to p from one standpoint w1, “Yes” to p from another standpoint w2
(inconsistency)
“Yes” to p from w1, “No” to p to w1
(incoherence)
58. 3 grades of belief inconsistency
(a) Bxp Bxp
(b) Bxp Bxp
(c) Bx(p p)
2 norms of rationality
(CON) a1(p) = 1 a2(p) = 0
(COH) ai(p) = 1 ai(p) 0
What can “Yes and No” mean?
A bivalentist answerhood from a non-bivalentist perspective
“Yes” to p from one standpoint w1, “Yes” to p from another standpoint w2
(inconsistency)
“Yes” to p from w1, “No” to p to w1
(incoherence)
59. 3 grades of belief inconsistency
(a) Bxp Bxp
(b) Bxp Bxp
(c) Bx(p p)
2 norms of rationality
(CON) a1(p) = 1 a2(p) = 0
(COH) ai(p) = 1 ai(p) 0
What can “Yes and No” mean?
A bivalentist answerhood from a non-bivalentist perspective
“Yes” to p from one standpoint w1, “Yes” to p from another standpoint w2
(inconsistency)
“Yes” to p from w1, “No” to p to w1
(incoherence)
60. 3 grades of belief inconsistency
(a) Bxp Bxp
(b) Bxp Bxp
(c) Bx(p p)
2 norms of rationality
(CON) a1(p) = 1 a2(p) = 0
(COH) ai(p) = 1 ai(p) 0
What can “Yes and No” mean?
A bivalentist answerhood from a non-bivalentist perspective
“Yes” to p from one standpoint w1, “Yes” to p from another standpoint w2
(inconsistency)
“Yes” to p from w1, “No” to p to w1
(incoherence)
61. 3 grades of belief inconsistency
(a) Bxp Bxp
(b) Bxp Bxp
(c) Bx(p p)
2 norms of rationality
(CON) a1(p) = 1 a2(p) = 0
(COH) ai(p) = 1 ai(p) 0
What can “Yes and No” mean?
Non-bivalentist answers to a (single) bivalentist question
“Yes” to p from one standpoint w1, “Yes” to p from another standpoint w2
(inconsistency)
“Yes” to p from w1, “No” to p from w1
(incoherence)
62. (At least) 3 sorts of ensuing propositional attitudes
Bivalentism, Paracompletism
Quine, Davidson, Lokhorst: (CON) (COH)
Paraconsistentism
Da Costa: (CON) (COH), but not (COH) (CON)
Dialethism
Priest: (COH) does not hold (dialetheism)
Does paracoherence make sense?
ai(p) = {1,0}
63. (At least) 3 sorts of ensuing propositional attitudes
Bivalentism, Paracompletism
Quine, Davidson, Lokhorst: (CON) (COH)
Paraconsistentism
Da Costa: (CON) (COH), but not (COH) (CON)
Dialethism
Priest: (COH) does not hold (dialetheism)
Does paracoherence make sense?
ai(p) = {1,0}
64. (At least) 3 sorts of ensuing propositional attitudes
Bivalentism, Paracompletism
Quine, Davidson, Lokhorst: (CON) (COH)
Paraconsistentism
Da Costa: (CON) (COH), but not (COH) (CON)
Dialethism
Priest: (COH) does not hold (dialetheism)
Does paracoherence make sense?
ai(p) = {1,0}
65. (At least) 3 sorts of ensuing propositional attitudes
Bivalentism, Paracompletism
Quine, Davidson, Lokhorst: (CON) (COH)
Paraconsistentism
Da Costa: (CON) (COH), but not (COH) (CON)
Dialetheism
Priest: (COH) does not hold (dialetheism)
Does paracoherence make sense?
ai(p) = {1,0}
72. Absolutists:
(+) are right to claim that a general theory of meaning requires a universal
standard for understanding
(–) miss the point in focusing the problem upon truth and only truth
Relativists:
(+) are right to claim that alternative reasonings may prevail in different
contexts of reasoning
(-) lose track of common rationality by equating plurality with relativity
73. Absolutists:
(+) are right to claim that a general theory of meaning requires a universal
standard for understanding
(–) miss the point in focusing the problem upon truth and only truth
Relativists:
(+) are right to claim that alternative reasonings may prevail in different
contexts of reasoning
(–) lose track of common rationality by equating plurality with relativity
74. QAS:
(+) reconciles opposite standpoints within a common framework where
the classical truth-functions v are replaced by verdict-functions A
(+) the real bearer of meaning is not a sentence, but its statement
(+) an answer to the problem of logical charity is in the question, viz. the
statement-forming operator Q that is attached to any sentence
75. References
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Phenomenological Research, Vol. 49, pp. 431-46
Davidson, D. (1973): “On radical interpretation”, Dialectica, Vol. 27, pp. 313-28
Frege, G. (1919): “Die Verneinung”, published in M. Black and P. T. Geach (eds.),
Translations from the Philosophical Writings of Gottlob Frege, Blackwell, Oxford (1960)
Lokhorst, G.J. (1998): “The Logic of Logical Relativism”, Logique et Analyse, 161-162-
163, pp. 57-65
Priest, G. (1979): “The Logic of Paradox”, Journal of Philosophical Logic, Vol. 8, pp.
219-41
Quine, W.V.O. (1960): Word and Object, MIT Press
Quine, W.V.O. (1973): The Roots of Reference, Open Court Publishing, La Salle (Illinois)
Quine, W.V.O. (2004): Philosophy of Logic, Harvard University Press (2nd edition)
Searle, J. (1969): Speech Acts, Cambridge University Press
Searle, J. Vanderveken, D. (1985): Foundations of Illocutionary Logic, N.-Y.,
Cambridge University Press
Suszko, R. (1977): “The Fregean axiom and Polish mathematical logic in the 1920’s”,
Studia Logica, Vol. 36, pp. 377-80
Williams, J.N. (1981): “Inconsistency and contradiction”, Mind, Vol. 90, pp. 600-2
77. A difference between conditional and the other logical constants:
, , are committal upon their components:
to give an answer to p, pq, pq is to give answers about p and q
is not committal upon its components:
An answer can be given to pq without giving any one about p and q
Frege-Geach’s (Embedding) Problem, aka Frege’s Point:
Force-indicators operate only on complete sentences, and never occur
significantly within the scope of a logical or sentential connective.
Frege’s Point: ‘├(p q)’ is a correct operation, whereas ‘├p ├q’ is not
Logical constants do not connect statements but, rather, sentences
Statements: sentences marked with force-indicators
78. A difference between conditional and the other logical constants:
, , are committal upon their components:
to give an answer to p, pq, pq is to give answers about p and q
is not committal upon its components:
An answer can be given to pq without giving any one about p and q
Frege-Geach’s (Embedding) Problem, aka Frege’s Point:
Force-indicators operate only on complete sentences, and never occur
significantly within the scope of a logical or sentential connective.
Frege’s Point: ‘├(p q)’ is a correct operation, whereas ‘├p ├q’ is not
Logical constants do not connect statements but, rather, sentences
Statements: sentences marked with force-indicators
79. A difference between conditional and the other logical constants:
, , are committal upon their components:
to give an answer to p, pq, pq is to give answers about p and q
is not committal upon its components:
An answer can be given to pq without giving any one about p and q
Frege-Geach’s (Embedding) Problem, aka Frege’s Point:
Force-indicators operate only on complete sentences, and never occur
significantly within the scope of a logical or sentential connective.
Frege’s Point: ‘├(p q)’ is a correct operation, whereas ‘├p ├q’ is not
Logical constants do not connect statements but, rather, sentences
Statements: sentences marked with force-indicat
80. A difference between conditional and the other logical constants:
, , are committal upon their components:
to give an answer to p, pq, pq is to give answers about p and q
is not committal upon its components:
An answer can be given to pq without giving any one about p and q
Frege-Geach’s (Embedding) Problem, aka Frege’s Point:
Force-indicators operate only on complete sentences, and never occur
significantly within the scope of a logical or sentential connective.
Frege’s Point: ‘├(p q)’ is a correct operation, whereas ‘├p ├q’ is not
Logical constants do not connect statements but, rather, sentences
Statements: sentences marked with force-indicators ors
81. A difference between conditional and the other logical constants:
, , are committal upon their components:
to give an answer to p, pq, pq is to give answers about p and q
is not committal upon its components:
An answer can be given to pq without giving any one about p and q
Frege-Geach’s (Embedding) Problem, aka Frege’s Point:
Force-indicators operate only on complete sentences, and never occur
significantly within the scope of a logical or sentential connective
Frege’s Point: ‘├(p q)’ is a correct operation, whereas ‘├p ├q’ is not
Logical constants do not connect statements but, rather, sentences
Statements: sentences marked with force-indicators
82. A difference between conditional and the other logical constants:
, , are committal upon their components:
to give an answer to p, pq, pq is to give answers about p and q
is not committal upon its components:
An answer can be given to pq without giving any one about p and q
Frege-Geach’s (Embedding) Problem, aka Frege’s Point:
Force-indicators operate only on complete sentences, and never occur
significantly within the scope of a logical or sentential connective
Frege’s Point: ‘├(p q)’ is a wff, whereas ‘├p ├q’ is not
Logical constants do not connect statements but, rather, sentences
83. Frege (1919):
(a) “If the accused was in Rome at the time of the deed, he did not commit
the murder. He was in Rome at this time. Therefore he did not commit the
crime.”
p: the accused was in Rome at the time of the deed
q: he (the accused) did committ the murder
An inference the form: ├(p q), ├p, ├q (Modus Ponens)
(b) “If the accused was in Rome at the time of the deed, he did not commit
the murder. He did commit the murder. Therefore he was not in Rome at
this time.”
An inference the form: ├ (p q), ├q, ├p (Modus Tollens)
84. Frege (1919):
(a) “If the accused was in Rome at the time of the deed, he did not commit
the murder. He was in Rome at this time. Therefore he did not commit the
crime.”
p: the accused was in Rome at the time of the deed
q: he did commit the murder
An inference the form: ├(p q), ├p, ├q (Modus Ponens)
(b) “If the accused was in Rome at the time of the deed, he did not commit
the murder. He did commit the murder. Therefore he was not in Rome at
this time.”
An inference the form: ├ (p q), ├q, ├p (Modus Tollens)
85. Frege (1919):
(a) “If the accused was in Rome at the time of the deed, he did not commit
the murder. He was in Rome at this time. Therefore he did not commit the
crime.”
p: the accused was in Rome at the time of the deed
q: he did commit the murder
An inference the form: ├(p q), ├p, ├q (Modus Ponens)
(b) “If the accused was in Rome at the time of the deed, he did not commit
the murder. He did commit the murder. Therefore he was not in Rome at
this time.”
An inference the form: ├ (p q), ├q, ├p (Modus Tollens)
86. Frege (1919):
(a) “If the accused was in Rome at the time of the deed, he did not commit
the murder. He was in Rome at this time. Therefore he did not commit the
crime.”
p: the accused was in Rome at the time of the deed
q: he did commit the murder
An inference the form: ├(p q), ├p, ├q (Modus Ponens)
(b) “If the accused was in Rome at the time of the deed, he did not commit
the murder. He did commit the murder. Therefore he was not in Rome at
this time.”
An inference the form: ├ (p q), ├q, ├p (Modus Tollens)
87. What of
(c) “If the accused was in Rome at the time of the deed, he did not commit
the murder. The accused was not in Rome at the time of the deed. (…)”
An inference the form: ├ (p q), ├p, … therefore ├ q ?
(d) “If the accused was in Rome at the time of the deed, he did not commit
the murder. I do not say that he was in Rome at the time of the deed. (…)”
An inference the form: ├ (p q), ┤q, … therefore ├ p ?
2 paradoxical side-effects of the “classical” (mainstream) conditional:
(c) entails everything if p is asserted, in classical (bivalent) logics
(d) is reducible to (c), according to Frege’s thesis of equivalence
88. What of
(c) “If the accused was in Rome at the time of the deed, he did not commit
the murder. The accused was not in Rome at the time of the deed. (…)”
An inference the form: ├ (p q), ├p, … therefore ├ q ?
(d) “If the accused was in Rome at the time of the deed, he did not commit
the murder. I do not say that he was in Rome at the time of the deed. (…)”
An inference the form: ├ (p q), ┤q, … therefore ├ p ?
2 paradoxical side-effects of the “classical” (mainstream) conditional:
(c) entails everything if p is asserted, in classical (bivalent) logics
(d) is reducible to (c), according to Frege’s thesis of equivalence
89. What of
(c) “If the accused was in Rome at the time of the deed, he did not commit
the murder. The accused was not in Rome at the time of the deed. (…)”
An inference the form: ├ (p q), ├p, … therefore ├ q ?
(d) “If the accused was in Rome at the time of the deed, he did not commit
the murder. I do not say that he did commit the murder. (…)”
An inference the form: ├ (p q), ┤q, … therefore ├ p ?
2 paradoxical side-effects of the “classical” (mainstream) conditional:
(c) entails everything if p is asserted, in classical (bivalent) logics
(d) is reducible to (c), according to Frege’s thesis of equivalence
90. What of
(c) “If the accused was in Rome at the time of the deed, he did not commit
the murder. The accused was not in Rome at the time of the deed. (…)”
An inference the form: ├ (p q), ├p, … therefore ├ q ?
(d) “If the accused was in Rome at the time of the deed, he did not commit
the murder. I do not say that he did commit the murder. (…)”
An inference the form: ├ (p q), ┤q, … therefore ├ p ?
2 paradoxical side-effects of the “classical” (mainstream) conditional:
(c) entails everything if p is asserted, in classical (bivalent) logics
(d) is reducible to (c), according to Frege’s thesis of equivalence
91. What of
(c) “If the accused was in Rome at the time of the deed, he did not commit
the murder. The accused was not in Rome at the time of the deed. (…)”
An inference the form: ├ (p q), ├p, … therefore ├ q ?
(d) “If the accused was in Rome at the time of the deed, he did not commit
the murder. I do not say that he did commit the murder. (…)”
An inference the form: ├ (p q), ┤q, … therefore ├ p ?
2 paradoxical side-effects of the “classical” (mainstream) conditional:
(c) entails everything if p is asserted, in classical (bivalent) logics
(d) is reducible to (c), according to Frege’s thesis of equivalence
92. What of
(c) “If the accused was in Rome at the time of the deed, he did not commit
the murder. The accused was not in Rome at the time of the deed. (…)”
An inference the form: ├ (p q), ├p, … therefore ├ q ?
(d) “If the accused was in Rome at the time of the deed, he did not commit
the murder. I do not say that he did commit the murder. (…)”
An inference the form: ├ (p q), ┤q, … therefore ├ p ?
2 paradoxical side-effects of the “classical” (mainstream) conditional:
(c) entails everything if p is asserted, in classical (bivalent) logics
(d) is reducible to (c), according to Frege’s thesis of equivalence
93. What of
(c) “If the accused was in Rome at the time of the deed, he did not commit
the murder. The accused was not in Rome at the time of the deed. (…)”
An inference the form: ├ (p q), ├p, … therefore ├ q ?
(d) “If the accused was in Rome at the time of the deed, he did not commit
the murder. I do not say that he did commit the murder. (…)”
An inference the form: ├ (p q), ┤q, … therefore ├ p ?
2 paradoxical side-effects of the “classical” (mainstream) conditional:
(c) entails everything if p is asserted, in classical (bivalent) logics
(d) is reducible to (c), according to Frege’s Equivalence Thesis
94. An alternative definition of conditional: commitment as a bet
QAS is a question-answer game upon components:
- this game relies upon behavioral rules, i.e. answerhood-conditions
- whoever does not reply correctly does not even play the game
A strengthened set of rules for the conditional p q:
- the answerer must assert the antecedent to use conditional meaningfully
- whoever does not assert p is compelled to reject any commitment about
the whole pq
If the speaker does not assert p in pq, then:
- (s)he is not committed at all about q
- (s)he does not assert pq and, therefore, rejects it(s being true)
- to reject (p q) is not tantamount to assert its negation!
95. An alternative definition of conditional: commitment as a bet
QAS is a question-answer game upon components:
- this game relies upon behavioral rules, i.e. answerhood-conditions
- whoever does not reply correctly does not even play the game
A strengthened set of rules for the conditional p q:
- the answerer must assert the antecedent to use conditional meaningfully
- whoever does not assert p is compelled to reject any commitment about
the whole pq
If the speaker does not assert p in pq, then:
- (s)he is not committed at all about q
- (s)he does not assert pq and, therefore, rejects it(s being true)
- to reject (p q) is not tantamount to assert its negation!
96. An alternative definition of conditional: commitment as a bet
QAS is a question-answer game upon components:
- this game relies upon behavioral rules, i.e. answerhood-conditions
- whoever does not reply correctly does not even play the game
A strengthened set of rules for the conditional p q:
- the answerer must assert the antecedent to use conditional meaningfully
- whoever does not assert p is compelled to reject any commitment about
the whole pq
If the speaker does not assert p in pq, then:
- (s)he is not committed at all about q
- (s)he does not assert pq and, therefore, rejects it(s being true)
- to reject (p q) is not tantamount to assert its negation!
97. An alternative definition of conditional: commitment as a bet
QAS is a question-answer game upon components:
- this game relies upon behavioral rules, i.e. answerhood-conditions
- whoever does not reply correctly does not even play the game
A strengthened set of rules for the conditional p q:
- the answerer must assert the antecedent to use conditional meaningfully
- whoever does not assert p is compelled to reject any commitment about
the whole pq
If the speaker does not assert p in pq, then:
- (s)he is not committed at all about q
- (s)he does not assert pq and, therefore, rejects it(s being true)
- to reject (p q) is not tantamount to asserting its negation!
98. Yes: if p, then q p q
--------------
If (yes: p), then (yes: q) p
q
Yes: not-(If p, then q) (p q)
---------------
If (yes: p), then (yes: p) p
q
115. K3 Ł3 P3 AR4
q ╞ p q
p ╞ p q
(p q) r ╞ (p r) (q r)
(p q) (r s) ╞ (p s) (r q)
(p q) ╞ p
p r ╞ (p q) r
p q, q r ╞ p r
p q ╞ q p
╞ p (q q)
╞ (p p) q
116. Advantages of the strengthened :
1. It avoids the Paradoxes of Material Implication
v( F q) = T (“Ex falso sequitur quodlibet”)
a1(p q) 1 when a1(p) = 0 and a1(q) = 1
v(p T) = T (“Verum sequitur ex quodlibet”)
a1(p q) 1 when a1(p) = 0
2. It requires rejectivism, by assigning an essential occurrence to denial
Assertibility- and deniability-conditions are not the same for and :
A(p q) A(p q) only in the light of QAS
the difference holds only if denial and negative assertion differ
117. Advantages of the strengthened :
1. It avoids the Paradoxes of Material Implication
v(F q) = T (“Ex falso sequitur quodlibet”)
a1(p q) 1 when a1(p) = 0 and a1(q) = 1
v(p T) = T (“Verum sequitur ex quodlibet”)
a1(p q) 1 when a1(p) = 0
2. It requires rejectivism, by assigning an essential occurrence to denial
Assertibility- and deniability-conditions are not the same for and :
A(p q) A(p q) only in the light of QAS
the difference holds only if denial and negative assertion differ
118. Advantages of the strengthened :
1. It avoids the Paradoxes of Material Implication
v(F q) = T (“Ex falso sequitur quodlibet”)
a1(p q) 1 when a1(p) = 0 and a1(q) = 1
v(p T) = T (“Verum sequitur ex quodlibet”)
a1(p q) 1 when a1(p) = 0
2. It requires rejectivism, by assigning an essential occurrence to denial
Assertibility- and deniability-conditions are not the same for and :
A(p q) A(p q) only in the light of QAS
the difference holds only if denial and negative assertion differ
121. Inconvenients of the strengthened :
1. The difference is irrelevant, according to Suszko’s Thesis
There is no substantial difference between 01 and 00
Both logical values belong to the same class of undesignated values
play the same role in logic as a theory of consequence
2. Accordingly, it conflates conditional and biconditional
a1(p q) = 1 iff a1(q p) = 1, therefore a1(p q) = 1 iff a1(p q) = 1
122. Inconvenients of the strengthened :
1. The difference is irrelevant, according to Suszko’s Thesis
There is no substantial difference between 01 and 00
Both logical values belong to the same class of undesignated values
play the same role in any theory of consequence
2. Accordingly, it conflates conditional and biconditional
a1(p q) = 1 iff a1(q p) = 1, therefore a1(p q) = 1 iff a1(p q) = 1
123. Inconvenients of the strengthened :
1. The difference is irrelevant, according to Suszko’s Thesis
There is no substantial difference between 01 and 00
Both logical values belong to the same class of undesignated values
play the same role in any theory of consequence
2. Accordingly, it conflates conditional and biconditional
a1(p q) = 1 iff a1(q p) = 1, therefore a1(p q) = 1 iff a1(p q) = 1
125. A way out: rejectivism against Suszko’s Thesis
There is an essential difference between denial and assertion
01 and 00 are not only designated values, but also:
A(pq) = 01 is the value of a negative assertion: an anti-designated value
(pq) D–
A(pq) = 00 is not the value of an assertion at all: a non-designated value
(pq) D
If A(pq) = 01, then ╞AR4 p q and p ╞AR4 q
I cannot assert p without rejecting q
If A(pq) = 00, then ╡AR4 p q but not p ╡AR4 q
I can reject p without rejecting q
126. A way out: rejectivism against Suszko’s Thesis
There is an essential difference between denial and assertion
01 and 00 are not only designated values, but also:
A(pq) = 01 is the value of a negative assertion: an anti-designated value
(pq) D–
A(pq) = 00 is not the value of an assertion at all: a non-designated value
(pq) D
If A(pq) = 01, then ╞AR4 p q and p ╞AR4 q
I cannot assert p without rejecting q
If A(pq) = 00, then ╡AR4 p q but not p ╡AR4 q
I can reject p without rejecting q
127. A way out: rejectivism against Suszko’s Thesis
There is an essential difference between denial and assertion
01 and 00 are not only designated values, but also:
A(pq) = 01 is the value of a negative assertion: an anti-designated value
(pq) D–
A(pq) = 00 is not the value of an assertion at all: a non-designated value
(pq) D
If A(pq) = 01, then ╞AR4 p q and p ╞AR4 q
I cannot assert p without rejecting q
If A(pq) = 00, then ╡AR4 p q but not p ╡AR4 q
I can reject p without rejecting q
128. A way out: rejectivism against Suszko’s Thesis
There is an essential difference between denial and assertion
01 and 00 are not only designated values, but also:
A(pq) = 01 is the value of a negative assertion: an anti-designated value
(pq) D–
A(pq) = 00 is not the value of an assertion at all: a non-designated value
(pq) D
If A(pq) = 01, then ╞AR4 p q and p ╞AR4 q
I cannot assert p without rejecting q
If A(pq) = 00, then ╡AR4 p q but not p ╡AR4 q
I can reject p without rejecting q
129. Prospects
A revision (not a mere extension) of classical logic, within QAS
2 basic relations in logic:
- consequence (truth- and falsity-preservation)
- rejection (non-truth and non-falsity preservation)
1 universal relation, upstream of consequence and rejection:
Partition, as a structuration of universe:
- formal ontology (predicative dimension of a logical value)
- formal logic (answerhood dimension of a logical value)
A universal theory of negation:
- opposite-forming operators (predicative dimension)
- iterated answerhood (beyond Pavlov’s Logic of Truth and Falsehood)
130. Prospects
A revision (not a mere extension) of classical logic, within QAS:
- conditional (or implication) and sharing principle (in formal ontology)
- co-implication (dual of implication)
2 basic relations in logic:
- consequence (truth- and falsity-preservation)
- rejection (non-truth and non-falsity preservation)
1 universal relation, upstream of consequence and rejection
Partition, as a structuration of meaning:
- formal ontology (predicative dimension of a logical value)
- formal logic (answerhood dimension of a logical value)
A universal theory of negation:
- opposite-forming operators (predicative dimension)
- iterated answerhood (beyond Pavlov’s Logic of Truth and Falsehood)
131. Prospects
A revision (not a mere extension) of classical logic, within QAS:
- conditional (or implication) and sharing principle (in formal ontology)
- co-implication (dual of implication)
2 basic relations in logic:
- consequence (truth- and falsity-preservation)
- rejection (non-truth and non-falsity preservation)
1 universal relation, upstream of consequence and rejection
Partition, as a structuration of meaning:
- formal ontology (predicative dimension of a logical value)
- formal logic (answerhood dimension of a logical value)
A universal theory of negation:
- opposite-forming operators (predicative dimension)
- iterated answerhood (beyond Pavlov’s Logic of Truth and Falsehood)
132. Prospects
A revision (not a mere extension) of classical logic, within QAS:
- conditional (or implication) and sharing principle (in formal ontology)
- co-implication (dual of implication)
2 basic relations in logic:
- consequence (truth- and falsity-preservation)
- rejection (non-truth and non-falsity preservation)
1 universal relation, upstream of consequence and rejection
Partition, as a structuration of meaning:
- formal ontology (predicative dimension of a logical value)
- formal logic (answerhood dimension of a logical value)
A universal theory of negation:
- opposite-forming operators (predicative dimension)
- iterated answerhood (beyond Pavlov’s Logic of Truth and Falsehood)
133. 5th World Congress and School on Universal Logic (20-30 June 2015)
Workshop: “Non-Classical Abstract Logics”
(Fabien Schang, James Trafford)
http://www.uni-log.org/start5.html