LUNGA VITA AL NEGAZIONISMO!
mercoledì 4 dicembre 2019
LUNGA VITA AL NEGAZIONISMO!
LUNGA VITA AL NEGAZIONISMO!
mercoledì 12 giugno 2019
LA SCIENZA DELLA MONETA
DEFINIRE LA SCIENZA
domenica 12 agosto 2018
Prime difficoltà del neopositivismo
Nella discussione dei protocolli i neopositivisti erano convinti che non esistesse il rischio di errore quando descrivo i miei dati sensoriali ad esempio quando dico di vedere un cerchio di colore rosso. Ma chi può garantire che dicendo rosso io intendo riferirmi davvero alle stesse sensazioni cromatiche a cui gli altri si riferiscono? È il problema del solipsismo.
Alla critica del solipsismo si reagisce recuperando l' olismo duhem il quale spiegava che nessuna esperienza Può confutare un enunciato da sola ma solo in congiunzione con tutta una serie di altri enunciati così per alcuni neopositivisti ora è unicamente nel contesto di altri enunciati che è un'esperienza può costituire la conferma di un certo enunciato. Inoltre non si può parlare di confronto tra un enunciato è la realtà poi che si cadrebbe nella metafisica ma solo di confronto tra enunciati. Per alcuni positivisti come Neurath la verità non consiste più Nella corrispondenza dell'enunciato con la realtà ma nella coerenza tra enunciati. Altri neopositivisti come Schlick si ribellarono tenendo che una favola ben costruita potesse risultare altrettanto vero di una teoria fondata sulla esperienza.
Un'altra critica del neopositivismo era imperniata sui limiti della logica induttiva le leggi scientifiche sono enunciati universali e non possono quindi essere verificate da alcun numero finito di osservazioni come aveva già sostenuto Hume. Il neopositivismo deve quindi rinunciare al concetto di verificabilità sostituendolo con quello di conferma o di probabilità.
Un'altra critica riguardava i termini ambigui come per esempio fragile. Cosa significa non è possibile precisarlo per quanto sia senza dubbio un termine che descrive un'esperienza. Ci si deve Allora rassegnare all'idea che le teorie ci dicono più di quanto non sia direttamente osservabile hot empiricamente controllabile.
Reazione. La crisi del neopositivismo fa nascere la corrente antirealista. Gli Anti realisti si dividono in strumentalisti e costruttivisti. Per i primi gli enunciati teorici non vanno interpretati alla lettera bensì come regole utili alla predizione. Per i costruzioni sti vanno interpretati alla lettera ma non necessariamente creduti. In questo senso Bellarmino aveva ragione rispetto a galileo. A questo punto però la scienza deve rinunciare a spiegare le cose. Si ritorna così a Duhem: la scienza descrive ma non spiega.
Ma andiamo avanti con le critiche. La critica di popper. Per Popper l'esperienza non può costituire l'origine e nemmeno la giustificazione della nostra conoscenza, si considera infatti un razionalista critico. Crede che la teoria preceda e fondi l'esperienza anche se a quest'ultima spetta poi il ruolo di falsificare. Popper Infatti considera la critica alla logica induttiva come fatale ma mette a frutto la simmetria che riscontra tra verificazione e falsificazione di un enunciato per falsificare basta un'unica osservazione. Popper non utilizzare la falsificazione come criterio di significanza pur essendo in falsificabili le asserzioni della metafisica non sono suo parere privè di significato Ed anzi possono avere una parte importante nella crescita della conoscenza il realismo stesso è d'altronde una tesi metafisica. La teoria da preferire è quella più facilmente falsificabile.
Quine e la sua critica radicale al neo e a Popper. Partendo da Duhem e dalla sua tesi per cui un'ipotesi non è mai verificabile isolatamente nell'esperienza giunge a concludere che non esiste una distinzione tra enunciati analitici e denunciati sintetici. I primi Infatti sono caratterizzati dal fatto di non poter essere confutati dall'esperienza, ma come abbiamo appena visto tutti gli enunciati sono di questa natura. Per lui il controllo empirico consiste sempre in un confronto tra L'esperienza e l'insieme globale dei nostri enunciati, poi paragona quest'ultima ad una rete che tocca l'esperienza solo i bordi.
La critica del secondo wittgenstein. Il linguaggio ha un ruolo molto più complesso ed ampio di quello ha segnato gli dai neopositivisti. Vedi il concetto di gioco linguistico. Il significato di un termine deriva dall'uso più che dalle tavole di verità.
Non si può distinguere come avrebbero voluto fare i neopositivisti tra termini puramente osservativi e termini teorici. Esistono Infatti i termini che si riferiscono a oggetti non osservabili come elettrone neutrino eccetera che quindi dovremmo chiamare teorici. In particolare come osserva putnam i neopositivisti sbagliavano a credere che i termini teorici fossero introdotti per mezzo di quelli conservativi
Un'altra posizione neopositivista revocata in dubbio è quella che assimila spiegazione e previsione. Michael Scriven ha obiettato che la teoria di Darwin e spiega molte cose ma finora non ha permesso di fare alcuna previsione. Secondo Silvia Bromberg le leggi dell'ottica geometrica, data l'altezza di un palo e l'altezza del sole, ci consentono di prevedere la lunghezza dell'ombra gettata da quel palo, e questo, secondo hampel, costituirà anche la spiegazione di tale lunghezza, il che è senz'altro ragionevole. Ugualmente però, data la lunghezza dell'ombra e l'altezza del Sole sarebbe possibile prevedere l'altezza del palo ma in nessun modo questo potrebbe venir considerata come una spiegazione dell'altezza.
giovedì 28 settembre 2017
Evviva la terra piatta
Evviva la terra piatta
mercoledì 20 settembre 2017
Il primo dogma sfatato da Quine
L'affermazione analitica è quella vera per definizione, ovvero quella in cui tra il termine definito e l'espressione che definisce esiste una relazione di sinonimia.
La sinonimia esiste quando i due termini sono intercambiabili.
Quine ha buon gioco nel dimostrare che la sinonimia non esiste mai.
Esempio: ammettiamo che l'uomo sia definito come "essere razionale". Ma nella frase "uomo si scrive con quattro lettere" l'intercambiabilità tra definito e definizione viene palesemente meno.
Eppure Quine non dimostra l'inesistenza degli enunciati analitici ma solo il fatto che non sappiamo esattamente dire in cosa consista questa loro caratteristica.
Chiunque tra noi sa distinguere perfettamente gli enunciati analitici da quelli sintetici. Cio' è un chiaro indizio che la differenza esiste.
E' dunque molto più prudente concludere che la distinzione analitico/sintetico esista anche se non sappiamo definirla in modo completo.
sabato 3 giugno 2017
Addio all'empirismo
… 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….
… I agree with 1, 2, 3, and 5. In fact, I regard each of those propositions as either self-evident…
… 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…
… 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…
… 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)…
… 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?…
… 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…
… (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…
… (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…
… 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….
… (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…
… 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…
… 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,…
… 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…
…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…
… (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…
… 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…
… 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…
… 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…
… 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…
… 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….
… 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…
… 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)…
… 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)…
… (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"…
… 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…