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```Institute of Philosophy of Mind and
Cognition, Yang Ming University
Wen-fang Wang
Introduction
 A Past Work: We Need a New Unified Theory
for Conditionals
 Some Recent Reflections on Indictive
Conditionals
 Prof. G. Landini and His Talks


Introduction
A Past Work: We Need a New Unified Theory
for Conditionals
Some Recent Reflections on Indictive
Conditionals
Prof. G. Landini and His Talks
Indictive (指示) conditionals:
If no one killed Harry, then he died naturally.
If John is in the library now, Mary will be there too.
 Subjunctive (虛擬) or counterfactual (反事實)
conditionals:
If Mr. Ma were 7 feet tall, he would be over two
meters.
If Mr. Ma had not won the election in March of
2012, he would have resigned the presidency of
KMT.
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

(should, might, could) V ….”這樣的形式，而表達對過去事件的虛

could) have V+ed ….”這樣的形式。但大多數討論虛擬條件句的哲

the case that S1 V …, then it would be the case that S2 V ….”和”If it
were the case that S1 V+ed …, then it would be the case that S2
V+ed …. ”。換句話說，這些哲學家認為，虛擬條件句可以看作

the case that__”這個連接詞所組成的語句。

“(p > q)” or “(p  q)” (subjunctive or
counterfactual conditionals): “If it were the
case that p, then it would be the case that q”.
 “(p  q)” (indictive conditionals): “If it is the
case that p, then it is (will be) the case that q”.
 “(p  q)”: truth-functional conditionals, which
is equivalent to “(p  q)”.


case that q”或”(p  q)” 是否在意義上或至少

 若然，如何解釋與之有關的各種“悖論”？又

(assertibility)？為何這樣計算？
 若否，指示條件句的意義或真值條件為何？


① p ⊨ (q  p)
 ② p ⊨ (p  q)
 ③ ⊨(p  q) ∨ (q  p)
 ④ ((p ∧ q)  r) ⊨ ((p  r) ∨ (q  r))
 ⑤ (p  (q ∨ r)) ⊨ ((p  q) ∨ (p  r))
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[④的反例1] 前提：“如果丈夫爱慕妻子，并且妻子爱慕丈夫，那么

[④的反例2]“如果温度为0℃,并且压力为一个大气压，则水冻冰”为

[⑤的反例1] 前提：“如果婚姻不理想，那么或者丈夫不爱慕妻子，

[⑤的反例2] 如火车奔驰在沪宁线上，则或驰向上海，或驰向南京，

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(p  q)  (r  s) ⊨ (p  s)  (r  q)

2012/5/29 就 會 在 台 灣 。 因 此 ， 如 果 老 王
2012/5/29在南京，他2012/5/29就會在台灣，

(p  q) ⊨ p
(如果《聖經》所說的都為真，則上帝不存在)

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(p  q) ⊨ ((p  r)  q)

(2012/03/09)坐飛機直接來南京但飛機卻在空中爆炸，那麼他很

(q  r), (p  q) ⊨ (p  r)

(p  q) ⊨ (q  p)

(2012/03/10)放棄台獨主張，中國不會今天(2012/03/09)停止警

would be the case that q”或”(p > q)”或“(p 
q)”是否在意義上或至少在真值條件上與指

 若然，如何解釋它們之間的顯然差異？
 若否，虛擬條件句的意義或真值條件為何？


Introduction
 A Past Work: We Need a New Unified Theory
for Conditionals
Some Recent Reflections on Indictive
Conditionals
Prof. G. Landini and His Talks
Philosophy Department at CCU
Wen-fang Wang
Kiki Wang
1.
2.
3.
4.
OK Cases
Replies to OK Cases
IC Cases and Perspectives
Perspective Semantics

（1a）If Oswald hadn’t killed Kennedy, no one else
would have. (True)
（1b）If Oswald didn’t kill Kennedy, no one else did.
(False)
（1a）(A > B) (True)
（1b）(A  B) (False)


 D. Lewis, F. Jackson: Yes.
 R. Stalnaker, E. Admas, D. Edgingon: No.


 一個虛擬條件句”  ”在世界i中為真，若

 任何一個世界i都至少和其它的世界一樣相



 一個虛擬條件句”  ”在世界i中為真，若

（antecedently reasonably-close）於i的-世界

 任何一個  -世界i都至少跟其它的  -世界一


Lewis & Jackson理論的一個結果：
MOP：(  )  (  )。

MOP’：(  )  (  )。

 但”（1a）  （1b）” （也就是(A  B)  (A
 B) ）似乎是MOP’的一個反例！Lewis和
Jackson因而需要去說明這裡到底出了什麼



 一個虛擬條件句"  "以及一個指示條件句
"  "在世界i中為真，若且唯若，""在最


Stalnaker理論的一個結果：
MOP’：(  )  (  )。

 因而”（1a）  （1b）”（也就是(A  B) 
(A  B) ）構成MOP’的一個反例！

Lewis和Jackson最可能作出的答覆，是去堅

 實際上Oswald殺了Kennedy，而指示條件句

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The assertibility of a conditional ”(  )” and ”(  )” goes by
Pr(/).

Kennedy的機率是相當低的。
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The appeal to assertibility to explain away counterexamples may not always work. E.g., (  ); therefore .
The assertibility of ”  ” does not always go by Pr(/)。
(Kaufmann（2004）)

Stalnaker最可能採取的說法是：（1a）和
（1b）在實際上同樣為真，而這是因為在

Oswald沒有殺死Kennedy的世界中，並沒有

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“( ), therefore, ( )”雖非有效的推論，但在任

(reasonable)。

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Stalnaker的解釋蘊涵，數學上涉及條件句的許多

（modes）上的差別，而這似乎顯示說，兩著的差

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（4a）If New York City were in Georgia, New York City
(as well as the rest cities of Georgia) would be in the South.
（4b）If Georgia included New York City, George would
not be entirely in the South.
（5a）If superman were I, he would not be able to fly.
（5b）If I were superman, I would be able to fly.

deliberations）以決定一個虛擬條件句的真

(Nute 1981: 352)，而這些我們所想要保存的

To see some force of Nute’s claim, let us
consider the following two sentences:
(2a) If this penny were asbestos, then it would
not conduct electricity.
(2b) If this penny were asbestos, then some
asbestos would conduct electricity.
we believe that the properties being preserved
in the process of hypothetical deliberation need
not always be dispositional properties and need
not always be properties of entities involved in
the antecedent either. Consequently, while
Nute thinks that what is supposedly to be
preserved in the process of hypothetical
deliberation is a function of the antecedent
alone, we think rather that it is a function of
both the antecedent and the consequent of the
subjunctive conditional.
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「在從事假設性的考量時，一個語言社群所共同

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Kennedy被刺殺之前，忽略Kennedy現在被刺殺的這個

 但我們對這些世界所做出的選擇不僅依賴


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（或”(  )”）在世界i中為真，若且惟若，至少

A W-model is a quadruple <I, \$, s, [ ]>, where I and
\$ are as those in Lewis (1973). s is a selection
function from pairs of sentences, moods, and a
possible world i to sets of possible worlds such that,
if there is a sphere S of \$i such that S∩[], then
(i) s(,, mood, i)[] and (ii) s(,, mood,
i)∩S’ for every S’ of \$i such that S’∩[]; and
s(,, mood, i)= if otherwise. A conditional “
mood ” is true at a world i in a W-model M=<I, \$,
s, [ ]> iff either s(,, mood, i)= or there is an S
of \$i such that S∩s(,, mood, i)[].

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

Introduction
A Past Work: We Need a New Unified Theory
for Conditionals
 Some Recent Reflections on Indicative
Conditionals
Prof. G. Landini and His Talks



Lewis和Jackson認為指示條件句”(p  q)”與實質條件

Stalnaker認為指示條件句”(p  q)”與實質條件句”(p
 q)”有不同的真值條件，因而許多對後者來說有效

「直接推論」的挑戰；訴諸於有效推論與合理推論



A Curry sentence is a sentence C satisfying the condition that C iff (if
“C” is true then Q). There are infinitely many Curry sentences.
From these Curry sentences, one can infer that every sentence is true.
Here is one proof:
1. C iff if (“C” is true then Q)
known fact
2. “C” is true
Assumption
3. If “C” is true then Q
1, 2, T-schema, Transitivity
4. Q
2, 3, MP
5. If “C” is true then Q
2-4, CP
6. C
1, 5, MP
7. “C” is true
6, T-schema
8. Q
5, 7, MP

Here is another proof that every sentence is true:
1. C iff (if “C” is true then Q)
known fact
2. “C” is true iff C
T-schema
3. “C” is true iff (if “C” is true then Q) 1, 2, Transitivity
4. If “C” is true then (if “C” is true then Q) 3. Cl. Logic
5. If “C” is true then Q
4, Contraction
6. If (if “C” is true then Q) then “C” is true 3. Cl. Logic
7. “C” is true
5, 6, MP
8. Q
5, 7, MP



（(A  (A  B)) ⊨ (A  B)）以及CP，但
Contraction在Stalnaker的理論中仍然是有效的。

Pa0, if Pa0 then Pa1

Pa1, if Pa1 then Pa2

Pa2, if Pa2 then Pa3

…
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Pan-1, if Pan-1 then Pan

Pan
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that?）時的正確應用。H. Field （2008）has done a great
job toward (1) and (2), but a further work on (3) still needs
to be worked out.
Introduction
A Past Work: We Need a New Unified Theory
for Conditionals
Some Recent Reflections on Indictive
Conditionals
 Prof. G. Landini and His Talks
Career and Education:
Professor of Philosophy, 2001-present, U. of Iowa
Associate Professor 1992-2001, U. of Iowa
Assistant Professor, 1989-92, U. of Iowa
Ball State University, Assistant Professor 1985-88
Ph.D., Philosophy, Indiana University, May 1986
Awards and Publication:
1. Frege Notations: What they are and how they
mean, (Palgrave Macmillan for the series in
History of Analytic Philosophy, 2012)
2. Bertrand Russell Society 2011 Book Award, for
Russell (Routledge)
3. Bertrand Russell Society 2007 Book Award, for
Wittgenstein’s Apprenticeship With Russell
(Cambridge)
4. Bertrand Russell Society 1999 Book Award for
Russell’s Hidden Substitutional Theory (OUP).
5. 20 Reviews and 44 Articles.
Impredicative predicate:
Px  ()((y)(Gy  y)  x).
 indexical self-reference
This sentence is not true.
 ontological self-reference
Everything, including every proposition, is selfidentical.

Abstract. Poetic license is an essential feature of intentionality.
The mind is free to think about any objects, even objects with
logically incompatible properties. Some philosophers maintain
that a theory that embraces an ontology of non-existent objects is
indispensable to any account of the nature of intentionality. Any
such theory, however, must face paradoxes whose solutions
conflict with poetic license. In this paper, I propose a theory
which rejects the argument that an ontology of non-existents is
indispensable for any adequate account of intentionality. The
theory maintains that the intentionality of thought is produced by
the quantificational nature of the apparatus of thought. All de re
ascriptions of propositional attitudes must quantify over concepts
and respect simple-type stratification. There are no fictional
objects; there are concepts which, in the impredicative reflections
of quantificational thought, are presented as if objects of thought.
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Thinking is fundamentally quantificational, by
means of all and some, together with negation and
other logical operations.
I thought of something I would like to buy you for
Christmas, but I couldn’t get it because it doesn’t
exist. (Priest)
Some property is such that I thought of buying
you something that has that property for
Christmas, but I didn’t because everything fails to
have that property.
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De dicto thinking is quantificational, Socrates believe
that some unique morning star is a planet. i.e.,
Socrates believed that [xMx][Px].
So is de re thinking. E.g., Some unique morning star
is such that Socrates believed that it to be a planet.
This should not be written as [xMx] [Socrates
believed that Px]. It should be written as (F)
(E!(xMx) .&. Fzz Mx :&: Socrates believed
[xFx][Px]) .
Q: Is self-reference necessary for the production
A1：A2(含)以下的語句都不是真的。
A2：A3 (含)以下的語句都不是真的。
A3：A4 (含)以下的語句都不是真的。
A4：A5 (含)以下…………..
…………………………………………….

Yablo cannot at one and the same time render a
consecutive list and demand that the sentences
on it be semantically or pragmatically
interpreted in a particular way.
 Far from showing that a Liar paradox can be
produced without self-reference, Yablo has
failed even to have produced a paradox.

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