sabato 3 giugno 2017

Addio all'empirismo

Why I Am Not an Objectivist di Michel Huemer
Co sono molti motivi per non essere empiristi, il principale è che una buona filosofia serve sempre come bussola e quella dell’empirista è pessima.
In filosofia politica, per esempio, gli empiristi amano farsi chiamare oggettivisti. La loro visione è all’incirca questa:
… Objectivism are these five claims: (1) Reality is objective. (2) One should always follow reason and never think or act contrary to reason. (I take this to be the meaning of "Reason is absolute.") (3) Moral principles are also objective and can be known through reason. (4) Every person should always be selfish. (5) Capitalism is the only just social system….
Molti punti sono condivisibili…
… I agree with 1, 2, 3, and 5. In fact, I regard each of those propositions as either self-evident…
Ma è la filosofia di fondo ad essere tremendamente pasticciata e indigesta.
Vediamo i concetti cardine con cui litiga l’empirista.
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Partiamo con la diade senso/significato.
E’ importante distinguere. Vediamo un esempio che chiarisce tutto all’istante…
… Oedipus, famously, wanted to marry Jocaste, and as he did so, he both believed and knew that he was marrying Jocaste. The following sentence, in other words, describes what Oedipus both wanted and believed to be the case: (J) Oedipus marries Jocaste. However, Oedipus certainly did not want to marry his mother, and as he did so, he neither knew nor believed that he was marrying his mother. The following sentence, then, describes what Oedipus did not want or believe to be the case: (M) Oedipus marries Oedipus' mother. But yet Jocaste just was Oedipus' mother. That is, the word "Jocaste" and the phrase "Oedipus' mother" both refer to the same person. Therefore, if the meaning of a word is simply what it refers to, then "Jocaste" and "Oedipus' mother" mean the same thing. And if that is the case, then (J) and (M) mean the same thing. But then how could it be that Oedipus could believe what (J) asserts without believing what (M) asserts, if they assert the same thing?… What the example shows is that (J) and (M) do not express the same thought since Oedipus had the first thought and did not have the second thought… Thus, "Jocaste" and "Oedipus' mother" have the same reference, but different sense…
Attenzione in casi del genere a non confondere le parole con le idee
… I speak of the sense and reference of a word, not of an idea. The reason for this is that the sense of a word is the idea associated with it. Ideas do not have senses; they are senses…
Perché l’empirista non distingue a dovere? Avrà i suoi motivi (che qui non vediamo), sta di fatto che così facendo manda all’aria il senso comune.
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Altra distinzione criciale: analitico/sintetico.
… An analytic statement is defined to be one that is true in virtue of the meanings of the words involved… Peikoff shows in his article on the analytic/synthetic distinction (in ITOE) that, from his theory of meaning, it would follow that no truth can be synthetic. Take an example of a typical, allegedly synthetic statement: (A) All bachelors are less than 8 feet tall. and suppose that it is true. Then, since the meaning of "bachelors" includes all the bachelors in the world, including all of their characteristics, including their various heights, including (by hypothesis) the fact that they are all less than 8 feet, to say that there is a bachelor more than 8 feet tall would contradict the meaning of "bachelor". Hence, (A) is analytically true. Having made the sense/reference distinction, however, we see this is wrong. (A) is analytic only if it is true in virtue of the senses of the words involved (not their reference)…
Il rifiuto di questa distinzione è associato con il rifiuto della prima.
Quine, per esempio, ha dimostrato che la distinzione analitico/sintetico è artificiosa. Come ha fatto?
Partendo dalla definizione di analitico: un giudizio è analitico quando la sua verità discende dal significato delle premesse.
Ma cos’è il significato?
Molto empiricamente, è cio’ che accomuna due parole cosiddette sinonime l’una dell’altra.
La distinzione analitico/sintetico dipende quindi dalla relazione di sinonimia.
Ma la relazione di sinonimia non esiste, dimostrarlo è facile. Nessuna parola puo’ infatti essere perfettamente tradotta se non con se stessa. Tutte le parole hanno un senso differente, fosse anche solo perché si compongono di un numero di lettere differente.
Esempio: se A e B sono sinonimi allora si possono tra loro sostituire nella medesima frase mantenendo lo stesso valore di verità della frase stessa. Ma questo non è mai possibile, basta scegliere ad hoc la frase. Prendiamo questa frase che ha tutte le caratteristiche di una frase scelta ad hoc: “X è una parola formata solo da linee rette”. Sostituiamo A e B all’incognita e notiamo che il valore veritativo della frase cambia eccome. Ergo, A e B non sono sinonimi. Magari in tutte le frasi significative A e B sono sostituibili, ma nella frase escogitata ad hoc no.
Ora, se la relazione di sinonimia è un mito, lo è anche la distinzione analitico/sintetico.
Fine della dimostrazione.
Si sarà notato che in questa dimostrazione molto dipende dalla nozione  univoca che diamo al termine “significato”. Ebbene, se riprendiamo l’immediata distinzione senso/significato anche la dimostrazione di Quine traballa: il riferimento di A e B puo’ essere lo stesso e la relazione di sinonimia puo’ essere ripristinata senza dover essere necessariamente un mito.
Se quindi non esistono valide motivazioni per rinunciare alla distinzione analitico/sintetico, ne esistono di molto valide per non farlo…
… There are sentences like "Every rectangle has 4 sides," "Every bachelor is male," "Every cat is a cat," etc., which certainly appear, prima facie, to have something in common and to be different in some way from "Every rectangle is blue," "Every bachelor is a slob," etc. Every philosopher is able to reliably classify certain specimens of each category and to produce indefinitely many additional examples each of 'analytic' and 'synthetic' propositions that have never been explicitly discussed by any other philosopher before ("Every dodecahedron has 12 faces"). Is this not strong evidence that there is some distinction here?…
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Terza distinzione: conoscenza a priori/conoscenza osservativa.
Definizioni…
… By an item of "empirical knowledge" I mean something that is known that either is an observation or else is justified by observations. A priori knowledge is that which is not empirical… I do not say that the concepts required to understand it are innate or formed without the aid of experience. I only maintain that a priori knowledge is not logically based on observations. In other words, if x is an item of a priori knowledge, then there is no observation that is evidence for the truth of x - but we still know x to be true. This distinction is crucial. Perhaps some experiences have caused us to form certain concepts. And perhaps having these concepts enables us to understand the proposition, x. So our ability to understand the proposition depends on observation…
Anche qui l’empirista – avendo negato le precedenti distinzioni - si trova nell’infelice condizione di dover negare anche questa a tutta prima evidente.
Basta fare qualche esempio.
La logica – tanto per dirne una - è conoscenza a priori, non deriva da una percezione sensoriale…
… (1) Principles of logic are not observations. You do not perceive, by the senses, the logical relation between two propositions. You may be able to perceive that A is true, and you may be able to perceive that B is true; but what you can not perceive is that B follows from A…
Le verità logiche sono originarie…
… (2) The principles of logic can not in general be known by inference… Now it follows from (1) and (2) that: (3) The principles of logic are known a priori. For they are not observations (1) and they are not inferred from observations (2), but they are known. This is the definition of a priori knowledge…
Ma anche la matematica è conoscenza a priori, e attenzione a non ingannarsi…
… Consider the proposition (B) 1 + 1 = 2, which I know to be true. Is this proposition based on any observations? If so, what observations? In order to learn the concept '2', I probably had to make some observations. I might have been shown a pair of oranges and told, "This is two oranges."… As I previously explained, the issue is not whether observations were necessary in my coming to understand the equation (B) but whether any observation justifies the proposition, i.e., provides evidence of its truth…. Addition is not a physical operation. It is not the operation of physically or spatially bringing groups together, and the equation (B) does not assert that when you physically unite two distinct objects, you will wind up with two distinct objects at the end. Indeed, if it did, the equation would be wrong. It is possible, for example, to pour 1 liter of a substance and 1 liter of another substance together, and wind up with less than 2 liters total. (This happens because the liquids are partially miscible.) This does not refute arithmetic…. Even if my experiences with the oranges, the fingers, etc., including all the experiences that helped me form the concepts of '1', '2', and 'addition', were all a long series of hallucinations, I still know that 1+1=2….
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Ma anche l’etica è conoscenza a priori…
… (1) Moral principles are not observations. The content of every observation is descriptive. That is, you do not literally see, touch, hear, etc. moral value…
Qui bisogna fare attenzione: è la fallacia naturalistica a farci capire meglio cosa intendiamo dicendo che l’etica è conoscenza a priori.
Esempio: noi descriviamo una situazione e diciamo come sia giusto comportarsi. Ma il precetto non deriva da quella descrizione posta in premessa, se fosse così incorreremmo nell’errore di fallacia naturalistica.
Qualcuno potrebbe obbiettare: il dolore è male e il piacere è bene (piacere e dolore sono descrizioni di una condizione umana). Se fosse così basterebbe in effetti una descrizione per implicare un giudizio morale. Ma non è così! Il fatto che il dolore sia male non è affatto automatico, il dolore non è la premessa da cui inferiamo l’esistenza di un male…
… The only possible objection I can think of would be if one thought that the sensations of pleasure and pain are literally perceptions of moral value and evil… The cut didn't cause pain in virtue of its being bad; it caused pain in virtue of plain old, physical characteristics - just as all sensations are caused by physical phenomena. How cuts cause pain can be explained purely by descriptive physiology and physics, without any ethical claims… Moral principles can not be inferred from descriptive premises…
Vediamo qualche caso concreto in cui la fallacia naturalistica (o legge di Hume) viene violata. Un giudizio sul comunismo
… Communism causes poverty, makes people miserable, and takes away people's freedom. Therefore, communism is bad. The premise is apparently a descriptive and empirical fact, while the conclusion is evaluative. Assume the premise is true. My question: Does the conclusion follow from thatalone? No, the conclusion also depends upon the suppressed premises that poverty and misery are bad,…
Altro esempio: la libertà
… Freedom is necessary to our survival. Therefore, freedom is good. Again, assume the premise is true, and ask, Does the conclusion follow from that alone? No, because the argument presupposes that survival is good, and that survival is good is an evaluative premise. If survival is bad, then the conclusion to draw is that freedom is bad, not good…
Altro esempio: la sopravvivenza e la vita…
…I want to live. Eating is necessary to live (and also will not interfere with anything else I want). Therefore, I should eat. This requires the assumption that I ought to act on my desires, and/or that my desire to live is a morally acceptable one…
E’ spesso la sociobiologia, ovvero il filosofo morale sedotto dall’evoluzionismo, a cadere nella trappola della fallacia naturalistica.
Si tratta quasi sempre di filosofi/scienziati che si dichiarano empiristi, ecco il loro classico errore logico… 
… (iv) Social cooperation increases our evolutionary fitness. Therefore, we should cooperate. This presupposes that evolutionary fitness is good. One could try to prove this like so: (v) The process of evolution tends toward the survival of the fittest. Therefore, fitness is good. But this presupposes that survival is good and/or that what evolution tends towards is good… If one tries to show that x is good because it produces y, one must presuppose that y is good…
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Negato il fatto che si possa passare dalle osservazioni ai giudizi morali, possiamo per altro verso dare esempi concreti di conoscenza a priori che difficilmente possono essere negati…
… there is a great deal of other a priori knowledge. Here are some examples: A cause cannot occur later than its effect. Time is one-dimensional. If A and B have different heights, then either A is taller than B or B is taller than A. "Inside" is a transitive relation. It is not possible for something to be created out of nothing…
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Come si traduce la singolare posizione empirista su questioni che parrebbero ovvie ma che lui è costretto a negare?
Per esempio con una visione tutta sua della facoltà razionale dell’uomo.
Per un empirista la ragione assomiglia ad un elaboratore che prende i dati da altre facoltà, per esempio i sensi, e li tratta…
… Reason takes observations (and memories) as input and then, through a certain process (inference), turns out a certain output. This output, according to empiricists, can include a huge amount of knowledge, from my knowledge that the sun will rise tomorrow, to the most elaborate of scientific theories, but all of it is dependent on receiving some input from the senses and/or introspection…
La ragione non è fonte di conoscenza ma di mera elaborazione.
Per il non empirista – invece – la ragione produce anch’essa delle sue verità che poi tratta…
… I say that reason does not only operate on input provided to it by other faculties, but is also a faculty of direct awareness of certain things - namely, all the things listed above. This knowledge that originates in reason is direct in the same sense that perceptions are direct knowledge…
La ragione (pura) puo’ quindi conoscere anche a prescindere dalle altre facoltà, questa conoscenza si chiama conoscenza a priori…
… At the beginning of this section (section 3), I defined "a priori knowledge" only negatively, as that which is not empirical. It is now possible to provide the positive characterization: A priori knowledge is the knowledge of pure reason…
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E qui veniamo ad un altra distinzione immediata a cui il povero empirista deve rinunciare: universali/particolari.
Definizione di universale, facciamo il caso della bianchezza
… I have here two white pieces of paper. They are not the same piece of paper, but they have something in common: they are both white. What there are two of are called "particulars" - the pieces of paper are particulars. What is or can be common to multiple particulars are called "universals" - whiteness is a universal….
Gli universali sono fatti per discutere: solo l’universale puo’ “descrivere”
… A universal is a predicable: that is, it is the kind of thing that can be predicated of something. A particular can not be predicated of anything. For instance, whiteness can be predicated of things: you can attribute to things the property of being white (as in "This paper is white"). A piece of paper can't be predicated of something; you can't attribute the piece of paper as a property…
Sia chiaro: l’universale è una cosa, non un concetto…
… Whiteness is not a concept; it is a color. When I have the concept of whiteness in my mind, I do not have whiteness in my mind (no part of my mind is actually white)…
Nella conoscenza a priori il soggetto è sempre un universale. Nell’osservazione è sempre un particolare…
… Now I have said that reason gives us direct awareness of facts about universals: In other words, the knowledge of pure reason is that in which not only the predicate but also the subject is a universal. Observations, in contrast, we defined as direct knowledge in which the subject is a particular (for example, "This paper is white" expresses an observation)…
Il problema: gli universali esistono?…
… (1) Do universals (as defined above) exist? (2) If not, why does it seem as if they do? (i.e., why do we have all these words and ideas apparently referring to them and knowledge apparently about them?) (3) If they do, does their existence depend on the existence of particulars?… The people who answer #1 "Yes" are called "realists", and those who answer #1 "No" are called "nominalists"…
Da come si risponde a questa domanda si puo’ essere classificati in: nominalisti, realisti e immanentisti.
Il nominalismo è ovviamente falso, il realismo probabilmente falso…
… I am not going to try to refute nominalism here, because it is just obviously false. It is obvious that there is such a thing as whiteness, and that's all I have to say about that. (David Armstrong does a good job on it though in Nominalism and Realism.) It also seems clear to me that universals exist in particulars, and so immanent realism is true…
Purtroppo per lui l’empirista è spinto su posizioni nominaliste, ovvero “ovviamente false”. Si deve sobbarcare una mole di prove che non è in grado di portare per negare l’evidenza del senso comune.
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Riepilogo.
Accettare la distinzione senso/significato, analitico/sintetici, a priori/empirico, universale/particolare sembrerebbe ovvio, sembrerebbe la base per ogni filosofia fondata sul senso comune.
Eppure l’empirista non puo’ permetterselo. Se lo facesse delle fastidiose facoltà umane che vanno oltre i meri sensi entrerebbero in campo. E a lui la cosa sembra non piacere.
E di fronte a questa impossibilità come si comporta?
Ha due vie: 1) negare ogni valore al pensiero (filosofia) o 2) mettere in piedi una filosofia cervellotica.
Abbracciare una filosofia semplice, solida e fondata sul senso comune è una via preferibile, direi. Ma per farlo bisogna dire addio una volta per tutte all’empirismo.