pavel sebastian's List: logic&rationality

• Modern empiricism has been conditioned in large part by two dogmas. One is a belief in some fundamental cleavage between truths which are analytic, or grounded in meanings independently of matters of fact and truths which are synthetic, or grounded in fact. The other dogma is reductionism: the belief that each meaningful statement is equivalent to some logical construct upon terms which refer to immediate experience. Both dogmas, I shall argue, are ill founded. One effect of abandoning them is, as we shall see, a blurring of the supposed boundary between speculative metaphysics and natural science. Another effect is a shift toward pragmatism.
• • the fact that epistemology is renouncing to impose a deductive reasoning over recent theories of rationality may be grounded in the fact that the binary type of classical logic is overshadowed by probabilistic coherence, a constraint less formal and one which does not impose on one's belief to have a truth value. the relation between one's belief and reality can be mathematically calculated in terms of percentages ,  and not through, until recently used, correspondence truth. this is a further movement away form the postulated unity of reason in  the time of the Enlightenment. it is also the negation of predictability, certainty and the classical understanding of future. instead of future we should use risk, as a more comprehensive  notion of uncertainty and contingencies. until the beginning of the XX-th century, the future could still be envisioned in a chronological image, where capitalism would fall and socialism will be its rightful owner of the future.  but advanced technology and the fall of socialism left us in a situation from which, for the first time in history, there is no turning back, and without a horizon of expectancies for the time a venir.
• Kant conceived of an analytic statement as one that attributes to its subject no more than is already conceptually contained in the subject.
• This formulation has two shortcomings: it limits itself to statements of subject-predicate form, and it appeals to a notion of containment which is left at a metaphorical level.
• a statement is analytic when it is true by virtue of meanings and independently of fact.
• Meaning, let us remember, is not to be identified with naming.^1b Frege's example of 'Evening Star' and 'Morning Star' and Russell's of 'Scott' and 'the author of Waverly', illustrate that terms  can name the same thing but differ in meaning. The distinction between meaning and naming is no less important at the level of abstract terms. The terms '9' and 'the number of the planets' name one and the same abstract entity but presumably must be regarded as unlike in meaning; for astronomical observation was needed, and not mere reflection on meanings, to determine the sameness of the entity in question.
• With general terms, or predicates, the situation is somewhat different but parallel. Whereas a singular term purports to name an entity, abstract or concrete, a general term does not; but a general term is true of an entity, or of each of many, or of none.^2b The class of all entities of which a general term is true is called the extension of the term. Now paralleling the contrast between the meaning of a singular term and the entity named, we must distinguish equally between the meaning of a general term and its extension. The general terms 'creature with a heart' and 'creature with a kidney,' e.g., are perhaps alike in extension but unlike in meaning.
• It is indeed a commonplace in philosophy to oppose intention (or meaning) to extension, or, in a variant vocabulary, connotation to denotation.

  • The intension thus links the signifier to the sign's extension. Without intension of some sort, words can have no meaning.

  • The extension of a whole statement, as opposed to a word or phrase, is defined (since Frege 1892) as its truth value.
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  • • extension - Capacity of a concept or general term to include a greater or smaller number of objects; -- correlative of intension. (b) the class or set of objects to which a term refers; -- contrasted with intension, the logical specification which defines members of a class, being the set of attributes which are necessary and sufficient to recognize an object as a member of the class.

    • intension - The collective attributes, qualities, or marks that make up a complex general notion; the comprehension, content, or connotation;
• The Aristotelian notion of essence was the forerunner, no doubt, of the modern notion of intension or meaning. For Aristotle it was essential in men to be rational, accidental to be two-legged.
• Things had essences, for Aristotle, but only linguistic forms have meanings. Meaning is what essence becomes when it is divorced from the object of reference and wedded to the word.
• But now we have abandoned the thought of any special realm of entities called meanings. So the problem of analyticity confronts us anew.
• All other statements of the language are, Carnap assumes, built up of their component clauses by means of the familiar logical devices, in such a way that the truth value of any complex statement is fixed for each state-description by specifiable logical laws.
• A statement is then explained as analytic when it comes out true under every state-description.
• Just what it means to affirm synonymy, just what the interconnections may be which are necessary and sufficient in order that two linguistic forms be properly describable as synonymous, is far from clear; but, whatever these interconnections may be, ordinarily they are grounded in usage. Definitions reporting selected instances of synonymy come then as reports upon usage.
• I have in mind what Carnap calls explication -- an activity to which philosophers are given, and scientists also in their more philosophical moments. In explication the purpose is not merely to paraphrase the definiendum into an outright synonym, but actually to improve upon the definiendum by refining or supplementing its meaning. But even explication, though not merely reporting a pre-existing synonymy between definiendum and definiens, does rest nevertheless on other pre-existing synonymies.
• The matter may bc viewed as follows. Any word worth explicating has some contexts which, as wholes, are clear and precise enough to be useful; and the purpose of explication is to preserve the usage of these favored contexts while sharpening the usage of other contexts.
• In order that a given definition be suitable for purposes of explication, therefore, what is required is not that the definiendum in its antecedent usage be synonymous with the definiens, but just that each of these favored contexts of the definiendum taken as a whole in its antecedent usage, be synonymous with the corresponding context of the definiens.
• In formal and informal work alike, thus, we find that definition -- except in the extreme case of the explicitly conventional introduction of new notation -- hinges on prior relationships of synonymy.

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• Frege considered two puzzles about language and noticed, in each case, that one cannot account for the meaningfulness or logical behavior of certain sentences simply on the basis of the denotations of the terms (names and descriptions) in the sentence.
• One puzzle concerned identity statements and the other concerned sentences with subordinate clauses such as propositional attitude reports.
• To solve these puzzles, Frege suggested that the terms of a language have both a sense and a denotation, i.e., that at least two semantic relations are required to explain the significance or meaning of the terms of a language.
• Principle of Identity Substitution

• Consider the following argument:

    

  John believes that Mark Twain wrote Huckleberry Finn. 
   Mark Twain=Samuel Clemens. 
   Therefore, John believes that Samuel Clemens wrote Huckleberry Finn.

    

    This argument is not valid. There are circumstances in which the premises are true and the conclusion false. We have already described such circumstances, namely, one in which John learns the name ‘Mark Twain’ by reading Huckleberry Finn but learns the name ‘Samuel Clemens’ in the context of learning about 19th century American authors (without learning that the name ‘Mark Twain’ was a pseudonym for Samuel Clemens). John may not believe that Samuel Clemens wrote Huckleberry Finn. The premises of the above argument, therefore, do not logically entail the conclusion. So the Principle of Identity Substitution appears to break down in the context of propositional attitude reports. The puzzle, then, is to say what causes the principle to fail in these contexts. Why aren't we still saying something true about the man in question if all we have done is changed the name by which we refer to him?
• To explain these puzzles, Frege suggested that in addition to having a denotation, names and descriptions also express a sense. The sense of an expression accounts for its cognitive significance—it is the way by which one conceives of the denotation of the term.
• Using the distinction between sense and denotation, Frege can account for the difference in cognitive significance between identity statements of the form ‘a=a’ and those of the form ‘a=b’. Since the sense of ‘a’ differs from the sense of ‘b’, the components of the sense of ‘a=a’ and the sense of ‘a=b’ are different.
• Moreover, Frege proposed that when a term (name or description) follows a propositional attitude verb, it no longer denotes what it ordinarily denotes.
• Instead, Frege claims that in such contexts, a term denotes its ordinary sense. This explains why the Principle of Identity Substitution fails for terms following the propositional attitude verbs in propositional attitude reports.

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• the economists' conception of social welfare is too "flat," inso-
  far as it evaluates diverse social goods along the same metric.
• As a great deal of
  empirical work has shown, these legal rules, allocating basic entitlements, have
  effects on choices and preferences. Someone who has been given a legal entitle-
  ment —to chocolate bars, clean air, freedom from sexual harassment, environ-
  mental goods—may well value the relevant good more than he would if the
  good had been allocated to someone else in the first instance. The preference‐
  shaping effects of the initial allocation via law raise important questions for the
  analysis of law and free markets. They suggest that government and law may
  not be able to leave preferences "as they are."
• a problem with gross domestic product, as a measure of
  social well-being, is its obliviousness to distributional concerns. Free markets
  can help fuel economic growth, and economic growth can improve people's
  lives. But many citizens are not benefited by growth, and at a minimum gov-
  ernment should take steps to combat human deprivation and misery in the
  midst of growth. In any case, it is important to develop standards for measur-
  ing social well-being that allow people, in their capacity as citizens and voters,
  to focus on the issue of distribution.
• the free speech principle has been wrongly identified with free speech
  markets
• markets should be understood as a legal construct, to be
  evaluated on the basis of whether they promote human interests, rather than
  as a part of nature and the natural order, or as a simple way of promoting
  voluntary interactions.
• Against this view, I argue that the free speech principle is
  mostly about democratic deliberation, not about free markets.
• People's choices are a func-
  tion of the distinctive social role in which they find themselves, and we may
  act irrationally or quasi-rationally. In particular, this work points to the im-
  portant role of social norms involving fairness, reciprocity, and cooperation in
  producing individual choice. If we do not uncover the relationship between
  rationality and social norms, we will make major mistakes in designing policies
  to accomplish our goals.
• Sometimes people care not just about social
  outcomes, but also about the "meaning" of such outcomes, that is, the values
  expressed in and by the outcomes.This point very much bears on law, in such
  areas as environmental protection, race and sex equality, and occupational
  safety and health
• Achievement of social justice is a higher value than the protec-
  tion of free markets; markets are mere instruments to be evaluated by their
  effects.
• It is important not only to know
  what choices and preferences are, but also to know how they are formed, and
  whether they are really connected with human well-being.
• Unjust institutions
  can breed preferences that produce individual and collective harm. Severe dep-
  rivation—including poverty—can be an obstacle to the development of good
  preferences, choices, and beliefs.
• Above all, social norms are an important determinant of behavior, and
  they have received far too little attention from those interested in free markets,
  economic analysis of law, and social justice.
• constitutions should be "countercultural," in the sense
  that they should protect against those aspects of a country's culture and tradi-
  tions that are most likely to produce harm.
• In this light a society should be concerned not simply and not entirely
  with satisfying the preferences that people already have, but more broadly
  with providing freedom in the process of preference-formation. Social prac-
  tices, including law, will inevitably affect preferences. There is no way for a
  legal system to remain neutral with respect to preference formation. In these
  circumstances it is fully legitimate for government and law to try to shape
  preferences in the right way, not only through education, but also (for exam-
  ple) through laws forbidding racial discrimination, environmental degradation,
  and sexual harassment, and through efforts to encourage attention to public
  issues and to diverse points of view.
• In its usual
  form, economics offers an inadequate understanding of social welfare. Often it
  is concerned with the satisfaction of existing preferences.
• But free markets are a tool, to be used when they promote human
  purposes, and to be abandoned when they fail to do so.

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• Audi has defended a position he calls "fallibilistic foundationalism." He thinks that the foundationalist response is the only tenable option of the epistemic regress argument. This states that if every belief has to be justified by some other, then the only options are four: infinite regress, circularity, stopping at a belief that isn't knowledge, and stopping at a basic belief that is itself justified. If the only alternative is the fourth, then if one has knowledge, one has foundational knowledge. Audi considers that foundationalism is usually taken to be infallible. That is, it is normally associated with the view that knowledge is founded on basic beliefs that are axiomatic and necessarily true, and that the rest of knowledge is deduced from this set of beliefs. Audi thinks that foundationalism may be fallible, in the sense that the suprastructure of beliefs may be derived inductively from the basic beliefs, and hence may be fallible. He also thinks that basic beliefs need not be necessary truths, but merely have some structure which makes epistemic transition possible. For example, the belief that one is in the presence of an object arises causally from visual perception

• Alfred Tarski diagnosed the paradox as arising only in languages that are "semantically closed", by which he meant a language in which it is possible for one sentence to predicate truth (or falsehood) of another sentence in the same language (or even of itself). To avoid self-contradiction, it is necessary when discussing truth values to envision levels of languages, each of which can predicate truth (or falsehood) only of languages at a lower level. So, when one sentence refers to the truth-value of another, it is semantically higher. The sentence referred to is part of the "object language", while the referring sentence is considered to be a part of a "meta-language" with respect to the object language. It is legitimate for sentences in "languages" higher on the semantic hierarchy to refer to sentences lower in the "language" hierarchy, but not the other way around. This prevents a system from becoming self-referential.

• I.  Deductia se bazeaza pe reguli care, avînd niste premise adevarate, conduc la concluzii adevarate, inde­pendent de experienta.

    

  II.  Inductia conduce la concluzii pornind de la premise care se sprijina pe experienta.

    

  III.    Deductia   se   spijina   pe   legi   presupuse universale   (de   exemplu:   Toti  oamenii  sînt  muritori; Socrate este om; Deci, Socrate este muritor), adica pe propozitii în care se atribuie proprietati date (aici, a fi muritor) multimii elementelor unei clase (Toti oamenii). Aceste propozitii permit sa se infereze, pentru cazul în care o proprietate se aplica la toate elementele unei clase, ca aceasta proprietate se aplica si fiecarui element al clasei (Socrate este om; Deci Socrate este muritor).

    

  IV.   Inductia   "se   bazeaza"   (de   exemplu)   pe constatarea ca un anumit numar de indivizi ai unei clase particulare au o proprietate data si, pornind de la aceasta constatare, ea permite sa se infereze ca toti membii clasei în cauza au aceasta proprietate (de exemplu: Socrate este muritor, Platon este muritor, Aristotel este muritor; Socrate,   Platon   si  Aristotel   sînt   oameni;   deci   toti oamenii sînt muritori). Una dintre problemele pe care le ridica inductia este ca aceasta trecere de la particular la general poate conduce (si conduce adesea) la concluzii total eronate: Am vazut o mierla neagra; am vazut înca o mierla neagra; am mai vazut înca o mierla neagra; ...; toate mierlele sînt negre. în acest exemplu, concluzia este eronata pentru ca ignora posibilitatea existentei unor mierle albe.
• Dupa Goodman, diferenta dintre inductie si deductie se reduce la urmatorul fapt: problema deductiei este aceea a validitatii logilor logice (si în special a schemelor inferentiale, cf. cap. 2, § Inferente nondemonstrative, implicaturi si cunostinte comune), sau, altfel spus, problema demonstratiei; problema inductiei, în schimb, este numai aceea de a afla daca exista reguli care sa permita efectuarea unor predictii valide.