Frege (1848 - 1925)
Russell (1872 – 1970)
Wittgenstein (1889 – 1951)
Frege: tensiune in ceea ce priveste statutul logicii ca stiinta
- e normativa sau descriptiva?
- e constitutiva pentru gandire?
Care e relatia dintre cele doua aspecte?
- experimentul mental mult-dezbatut legat de posibilitatea existentei asa-zisilor extraterestri logici (logical aliens)
Frege (1848 - 1925)
Russell (1872 – 1970)
Wittgenstein (1889 – 1951)
Frege: tensiune in ceea ce priveste statutul logicii ca stiinta
- e normativa sau descriptiva?
- e constitutiva pentru gandire?
Care e relatia dintre cele doua aspecte?
- experimentul mental mult-dezbatut legat de posibilitatea existentei asa-zisilor extraterestri logici (logical aliens)
Russell:
I. 1910 - Principia Matematica: judecarea = o relatie dualista – intre un continut propozitional si o stare mentala
teorie intuitiva asupra adevarului /intuitional theory of truth (Griffin)
II. Teoria multirelationala a judecarii: o judecata are loc intre o minte si partile componente ale unei propozitii
teorie a adevarului corespondenta
a. 1910 – „On the Nature of Truth and Falsehood‟ - prima formulare
b. 1912 – Problemele filosofiei
c. 1913 – Teoria cunoasterii (nepublicata) – conceptul de forma logica
Critica lui Wittgenstein la Russell
Conceptia din 1) Notes on Logic (1914) - The proper theory of judgement must make it impossible to judge nonsense [NL: 95].
Every right theory of judgement must make it impossible for me to judge that this table penholders the book. Russell‟s theory does not satisfy this requirement [NL: 103]
- se apropie de Frege prin separarea continutului mental de cel propozitional
a intelege o propozitie = a-i stii conditiile de adevar
principiul bivalentei
Samburele conceptiei din Tractatus se regaseste in critica pe care Wittgenstein o face teoriei multirelationale a judecarii
2) Tractatus asupra limbajului
1. o prop e formata din nume si copula (verb)
2. similaritate intre propozitie si faptul din realitate pe care-l reprezinta
In ce masura aceste doua caracteristici ale complexitatii propozitionale dezvoltate in Notes on Logic se regasesc in Tractatus
“something [must be] identical in a picture and what it depicts, to enable the one to be a picture of the other at all”
Picture theory nu e numai o teorie despre semnificatia limbajului ci si o teorie a reprezentarii
- imaginea si continutul reprezentarii trebuie sa impartaseasca aceeasi structura
The notion of isomorphism implies that elements in the picture are univocally associated to elements in the situation to be represented, and that relations among those elements univocally correspond to relations among the elements of the situation to be pictured.
2. But the relation between names (for example the relational element in the proposition „aRb‟) need not be, and in fact is not, identical to the relation between particular elements in states of affairs.
identitatea posibilitatii de combinare intre faptul care reprezinta si cel reprezentat.
- nici conceptia nominalista nici cea realista nu surprind natura constituentilor propozitionali
Numele din Tractatus pastreaza un sens al formei din Note, insa nu se mai aplica numai la particulari.
Un nume presupune formele tuturor propozitiilor in care poate aparea (“the forms of all the propositions in which it can occur”)
Coceptia bipartita: propozitiile sunt fie tablouri, fie functii de adevar
Insa teoria picturala si teoria functiilor de adevar sunt una si aceeasi teorie.
Propozitiile logicii sunt construite prin aceeasi procedura ca si propozitiile moleculare.
operatorii propozitionali = reguli de formare a unor prop complexe din prop simple
Conectorii logici nu au continut reprezentational.
Adevarul logic devine o forma de adevar contingent: intr-o tautologie, propozitia care rezulta nu are sens deorece nu are propriu-zis conditii de adevar externe (fiind analitica, deci adevarata doar in virtutea formei) – ceea ce spun tautologiile sau contradictiile este faptul ca nu spun nimic (nu au continut informational).
Contingent truth – correspondence-truth – applies to non-logical propositions, to pictures, whereas logical truth to tautologies.
prop logicii nu reprezinta nicio situatie posibila – nu au subiect
Adevar: - empiric
- logic
Concluzie: ce pastreaza Wittgenstein din teoria lui Frege:
Wittgenstein rezolva contradictiile inerente teoriei fregeene despre logica considerand ca logica NU este o stiinta, prin urmare ea nu are continut empiric.
Logica este o imagine in care se oglindeste lumea. Ea constituie cadrul limbajului si al lumii.
Table of Contents
Introduction 5
Part One: Frege’s Conception of Logic
[1] Logic: Thoughts and the Predicate ‘True’ 17
[1.1] The Predicate „True‟ 17
[1.2] Thoughts 20
[2] Is Logic Normative or Descriptive? 26
[2.1] Laws of Truth and Laws of Thought 26
[2.2] From Laws of Thought to Laws of Truth: Logic as
Normative and Descriptive 29
[2.3] Normativity, Descriptivity, Generality 32
[3] Is Logic Formal? 37
[3.1] Formality of Logic and the Begriffsschrift 37
[3.2] Frege and Kant on the Formality of Logic 47
[3.3] Concluding Remarks 50
[4] Is Logic ‘Constitutive’ of Thought? 53
[4.1] The Idea of „Constitutivity‟, and its Problems 53
[4.2] Logical Aliens 57
[4.3] Some Interpretations 60
[4.4] Logic, Thought and Rationality 71
[4.5] Conclusion 76
Part Two: Russell on the Nature of Judgement
[5] Propositional Unity, Truth and Judgement in 1903-1905 80
[5.1] Terms and Propositions 80
[5.2] The Unity of the Proposition 87
[5.3] Truth and Judgement 91
[6] The Multiple Relation Theory of Judgement in 1910-1912 99
[6.1] Truth and the 1910 Multiple Relation Theory of Judgement 99
[6.2] The 1912 Multiple Relation Theory of Judgement 110
[7] The Multiple Relation Theory of Judgement in 1913 115
[7.1] Propositional Thought, Understanding and Judgement 115
[7.2] Logical Form 118
[7.3] Logical Form and Judgement 122
[7.4] Conclusion 130 Part Three: the Tractatus on Language and Logic
[8] Wittgenstein’s Criticism of Russell’s Theory of Judgement 133
[8.1] Intr
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