Mágikus erővel bír ez a könyv: bármilyen fitten is kezdtem bele, három mondat után azon kaptam magam, hogy ásítok. A hátsó borítóra ugyan ráírta valaki, hogy "a művelt nagyközönségnek is izgalmas és élvezhető olvasmány", de vagy nagyon el akarta adni a kötetet, vagy végzetesen máshogy definiáljuk a "nagyközönség" kifejezést. Szerény véleményem szerint ugyanis Popper egyszerűen tesz a laikusokra - laikus alatt értve mindenkit, akinek nem a Bernoulli-tétel volt a jele az óvodában. Ő csak és kizárólag balhitben tévelygő kollégáihoz beszél, azokhoz, akiket meg akar győzni arról, rosszul értik a tudománytörténet egyik legégetőbb problémáját, a "valószínűtlenségi logika" meg az "induktív módszerek" híveihez intézi szavait, azokhoz, akiknek eddig a létezéséről sem tudtam, de Popper megjelenéséig vélhetően uralták a tudományfilozófiát. Ennek következtében teljesen természetes, hogy olyan a szövegben haladni, mintha sós mocsáron lábalnék át (szembeszélben!), hisz a szerzőnek folyvást és kétséget kizáróan bizonyítania kell, amit állít, következésképpen olyan szavakat, mint az "egyszerű", a "valószínű" vagy a "véletlen" megpróbál matematikai képletekre lefordítani, és úgy általában, minden marginálisnak tűnő logikai problémát tíz oldalon keresztül fejteget, pedig én simán elhinném becsszóra is. Ja, és arról nem is beszéltem még, hogy lépten-nyomon olyan lábjegyzetekbe ütközünk, amelyek felhívják a figyelmünket, hogy Popper azóta kibővítette vagy elvetette a fenn taglalt gondolatmenetet, de ha erről többet akarunk tudni, akkor fordíttassuk le a Postscript c. munkáját, mert az sajna nincs meg magyarul. Na, hát így.



Mivel az eddigiekkel nyilván elvettem mindenki kedvét a könyv elolvasásától, kötelességemnek érzem, hogy legalább összefoglaljam, miről szól. Annál is inkább, mert közben meg ménkű fontos könyv, olyan szöveg, ami alapvetően forradalmasította a tudományos gondolkodást.

Popper tézise ugyanis az, hogy a tudományos állítások mércéje nem a verifikálhatóság (kb. bebizonyíthatóság), hanem a falszifikálhatóság (cáfolhatóság). Leegyszerűsített példával illusztrálva: ha én azt állítom, hogy minden egész szám háromszorosa páros szám lesz, akkor végtelen számú esetet tudok mondani, ami engem támaszt alá, de ez nem jelent semmit, mert ettől még az állítás nem lesz igaz. Viszont elég egy olyan esetet mondani, amikor a végösszeg páratlan, és háhá, máris falszifikáltuk az állítást. No most ennek számos következménye van, leginkább az, hogy Popper értelmezésében csak azok az állítások tekinthetőek tudományosnak, amelyek - legalább elméletben - cáfolhatóak. Az "Isten szeret téged" megállapítás például lehet, hogy igaz, lehet, hogy nem, sem megerősíteni, sem megcáfolni nem tudjuk, tehát nem tekinthető tudományos hipotézisnek*. A másik, tán még ennél is fontosabb hozadék, hogy Popper szemében a tudomány nem kész, megállapodott valami, saját metaforája szerint inkább olyan házra emlékeztet, amit felhúztunk ugyan, mert lakni csak kell valahol, de legyünk felkészülve rá, hogy ha úgy alakul, bármikor lebonthatjuk vagy áthelyezhetjük máshová. Nincs tehát végérvényes tudás, csak egyfajta ideiglenes állapot, állításaink addig érvényesek, amíg valaki nem jön a cáfolattal. De ez nem a tudomány relativizálása, dehogy, sőt: a tudomány fejlődésének záloga. Túl sok okos töltötte azzal egész szakmai pályafutását, hogy saját, egyszer kicsiszolt elméletét védte foggal-körömmel ahelyett, hogy maga próbálta volna megcáfolni azt - holott Popper szerint ez lenne a tisztességes eljárás, ettől haladunk előre. Vagy ahogy a szerző mondja: "a tudós ugyanis nem azért tudós, mert tudás, cáfolhatatlan igazság van a birtokában, hanem azért, mert állhatatosan és vakmerően kritikusan keresi az igazságot."

Újszerű és termékeny elmélet ez, amit az is jelez, hogy a társadalomtudományba is átszivárgott. Hogy mást ne mondjak, a nyílt társadalom egyik alapvető hivatkozási pontja lett belőle: “Az adott társadalmi szituációk résztvevőiként mindannyiunknak rendelkeznünk kell bizonyos nézetekkel, amelyek alapján cselekszünk. De milyen alapon cselekedjünk, amennyiben elfogadjuk, hogy nézeteink nagy valószínűséggel tévesek, de legalábbis a valóság hiányos vetületei. A válasz ugyanaz, mint amit Popper adott a tudományos módszerre: nézeteinket átmeneti igazságokként kell kezelni, és közben biztosítani kell az állandó felülvizsgálatot. Ez a nyílt társadalom alaptétele.” (Meg se mondom, ki mondta. A miniszterelnök úr szokta gyakran emlegetni, ha ideges.) Nyugodtan állíthatjuk hát, hogy Popper elvei egyfajta forradalmat eredményeztek a gondolkodásban. Kár, hogy olyan kínszenvedés volt olvasni. Mindegy, túl vagyok rajta. Majdnem olyan büszke vagyok erre, mintha kockákat növesztettem volna a hasamra.

* Ez a kritérium kifejezetten fontos, ha meg akarjuk különböztetni az áltudományokat a tudományoktól. Hisz az áltudománynak pont az a lényege, hogy nem ad lehetőséget a cáfolatra. Gondoljunk a laposföldesekre. Bármilyen ellenük szóló bizonyítékot laza csuklómozdulattal hamisítványnak, egy ellenséges környezet manipulációjának bélyegeznek. Ezzel abszurd szituációt teremtenek: világképükben a mellettük szóló "érvek" verifikálják állításaikat, de az ellenérvek is, mert minden ellenérv csak annak bizonyítéka, hogy létezik egy hatalmas ellenség, aki minden erejével el akarja leplezni az ő igazságukat. ( )

This is not for the general reader, even one particularly interested in philosophy or science, as am I. It addresses the philosophy of science in a manner similar to Wittgenstein's later characterization of his "Philosophical Investigations" as his attempts to untangle various confusions besetting discourse in that field.

Popper's tools are largely formalizations of scientific process and interpretation. This tends to give it somewhat the flavor of Whitehead's "Principia Mathematica", with some of its same advantages and disadvantages. With the advantage of formal exactitude comes the disadvantage (to the general reader) of having to deal with set theory, propositional logic, math and numbing precision about words. Also it seems that the more highly formalized is a system, the less interesting (even to philosophers and mathematicians) it comes to be, except as it may resolve major entanglements. Has anyone ever opened the "Principia" for help in solving a physics problem?

Fortunately, Popper does some untangling in a few interesting areas. For one, he demonstrates the supreme scientific importance, in a universal theory, of its falsifiability, and he shows the illogic of trying to formally prove any such theory. He shows also that it is not logical to assign a formal probability to the truth of a universal theory, even though some assessment can be made based on how easily a theory might be falsified and on how rigorous have been attempts at falsification.

Popper also emphasizes the importance of forming (falsifiable) hypotheses, quoting Novalis: "Hypotheses are nets; only he who casts catches". He concludes that there can be no formal process of generating them.

Popper also shows that (hypothesis aside) true induction in scientific analysis is an illusion and is in fact, where useful, deductive (mathematical induction notwithstanding; it is tautological).

I agree with Popper in so far as I follow him, but I sense that his major contributions here have already been accepted and entrained within current philosophy of science, making his arguments here primarily of historical importance today. He published originally in 1939, rewrote the book in English and re-published in 1959, and has added multiple and extensive appendices. He discusses therein (among many other things) the Einstein Podolsky Rosen paradox, obviously without mention of John Stewart Bell's 1964 paper and its relation, if any, to some of Popper's suggestions about entanglement.

A philosopher of science who has not read this book, if there be one, will want to add a star or two both for her greater appreciation of the formal arguments and for the historical aspects of interest. ( )

Should be required reading for every phd candidate in the sciences. Completely destroys the craft of the militant scientist. ( )

This book was hard to read, so I wanted to give it a 2/5 stars. However, it's important for introducing the idea of falsification as the benchmark for demarcating science against pseudoscience, even if today that stands on shaky ground (see Feyerabend, someone whose work I plan on reading next). And for that I wanted to give it a higher rating. So 3/5 it is.

I found a LOT of the text in this book to be obscure, not only in its writing style, but also allusions and references which were probably more clear for anyone reading this 80 years ago than today. He gets his argument against induction out quickly, and introduces falsifiability as a replacement shortly thereafter. Great. I think that was all done in the first 10 pages. Then there is a slew of chapters and text that was way over my head and didn't seem all that interesting anyways.

I liked the chapter on probability, even if it is a little outdated as well (for example, no mention of a Bayesian interpretation of probability). I've read that Popper later came to have a propensity interpretation of probability (yay C.S. Pierce!). Regardless, the whole interpretation of probability is interesting, and well worth the read here.

The next chapter, on quantum mechanics, which is the second last chapter, was also pretty fun. Turns out Popper's experiment wasn't tested until 1999 (!), where, to their surprise, they found the results corroborated his predictions. However, turns out this doesn't mean what Popper thought it would mean... for reasons I'm not really familiar with. It all seems very interesting... but who has the time? I also think that this chapter may have inspired the Bell tests (?), which is sort of amazing. 2015 was a big year for these tests, as some folks from the Kavli Institute of Nanoscience say they performed a "loop-hole free Bell test" ... although even that statement probably isn't true (but close!)

Anyways, fun book, but really obscure and boring for a LOT of it. I wish it had been written by someone like Richard Rorty, Daniel Dennett, or Ian Hacking. Although that's impossible, as they came after Popper.

I don't recommend reading the full thing. Instead, try this condensed version. text, but then read the full chapters on probability and quantum mechanics.

I'll end this review with the last few paragraphs from the book:

My investigation has traced the various consequences of the decisions and conventions—in particular of the criterion of demarcation—adopted at the beginning of this book. Looking back,
we may now try to get a last comprehensive glimpse of the picture of science and of scientific discovery which has emerged. (What I have here in mind is not a picture of science as a biological phenomenon, as an instrument of adaptation, or as a roundabout method of production: I have in mind its epistemological aspects.)
Science is not a system of certain, or well-established, statements; nor is it a system which steadily advances towards a state of finality. Our science is not knowledge (epistēmē): it can never claim to have attained truth, or even a substitute for it, such as probability.
Yet science has more than mere biological survival value. It is not only a useful instrument. Although it can attain neither truth nor probability, the striving for knowledge and the search for truth are still thestrongest motives of scientific discovery.
We do not know: we can only guess. And our guesses are guided by the unscientific, the metaphysical (though biologically explicable) faith in laws, in regularities which we can uncover—discover. Like Bacon, we might describe our own contemporary science—‘the method of rea-
soning which men now ordinarily apply to nature’—as consisting of ‘anticipations, rash and premature’ and of ‘prejudices’.
But these marvellously imaginative and bold conjectures or ‘anticipations’ of ours are carefully and soberly controlled by systematic tests. Once put forward, none of our ‘anticipations’ are dogmatically upheld. Our method of research is not to defend them, in order to prove how right we were. On the contrary, we try to overthrow them. Using all the weapons of our logical, mathematical, and technical armoury, we try to prove that our anticipations were false—in order to put forward, in their stead, new unjustified and unjustifiable anticipations, new ‘rash and premature prejudices’, as Bacon derisively called them.
It is possible to interpret the ways of science more prosaically. One might say that progress can ‘. . . come about only in two ways: by gathering new perceptual experiences, and by better organizing those which are available already’. But this description of scientific progress, although not actually wrong, seems to miss the point. It is too reminiscent of Bacon’s induction: too suggestive of his industrious gathering of the ‘countless grapes, ripe and in season’, from which he expected the wine of science to flow: of his myth of a scientific method that starts from observation and experiment and then proceeds to theories. (This legendary method, by the way, still inspires some of the newer sciences which try to practice it because of the prevalent belief that it is the method of experimental physics.)
The advance of science is not due to the fact that more and more perceptual experiences accumulate in the course of time. Nor is it due to the fact that we are making ever better use of our senses. Out of uninterpreted sense-experiences science cannot be distilled, no matter how industriously we gather and sort them. Bold ideas, unjustified anticipations, and speculative thought, are our only means for interpreting nature: our only organon, our only instrument, for grasping her. And we must hazard them to win our prize. Those among us who are unwilling to expose their ideas to the hazard of refutation do not take part in the scientific game.
Even the careful and sober testing of our ideas by experience is in its turn inspired by ideas: experiment is planned action in which every step is guided by theory. We do not stumble upon our experiences, nor do we let them flow over us like a stream. Rather, we have to be active: we have to ‘make’ our experiences. It is we who always formulate the questions to be put to nature; it is we who try again and again to put these question so as to elicit a clear-cut ‘yes’ or ‘no’ (for nature does
not give an answer unless pressed for it). And in the end, it is again we who give the answer; it is we ourselves who, after severe scrutiny, decide upon the answer to the question which we put to nature—after protracted and earnest attempts to elicit from her an unequivocal ‘no’.‘Once and for all’, says Weyl, with whom I fully agree, ‘I wish to record my unbounded admiration for the work of the experimenter in his struggle to wrest interpretable facts from an unyielding Nature who knows so well how to meet our theories with a decisive No—or with an inaudible Yes.’
The old scientific ideal of epistēmē—of absolutely certain, demonstrable knowledge—has proved to be an idol. The demand for scientific objectivity makes it inevitable that every scientific statement must remain tentative for ever. It may indeed be corroborated, but every corroboration is relative to other statements which, again, are tentative. Only in our subjective experiences of conviction, in our subjective faith, can we be ‘absolutely certain’.
With the idol of certainty (including that of degrees of imperfect certainty or probability) there falls one of the defences of obscurantism which bar the way of scientific advance. For the worship of this idol hampers not only the boldness of our questions, but also the rigour and the integrity of our tests. The wrong view of science betrays itself in the craving to be right; for it is not his
possession of knowledge, of irrefutable truth, that makes the man of science, but his persistent and
recklessly critical quest for truth.
Has our attitude, then, to be one of resignation? Have we to say that science can fulfill only its biological task; that it can, at best, merely prove its mettle in practical applications which may corroborate it? Are its intellectual problems insoluble? I do not think so. Science never pursues the illusory aim of making its answers final, or even probable. Its advance is, rather, towards an in
finite yet attainable aim: that of ever discovering new, deeper, and more general problems, and of subjecting our ever tentative answers to ever renewed and ever more rigorous tests.

( )

This volume was intended as a response to the Logical Positivists of the Vienna Circle. In the simplest terms, the Vienna Circle and their counterparts in England believed that if one could create an artificial language without ambiguities which employed terms that were linked directly back to observations of the world that all philosophic problems would be resolved. These philosophers were, in short, radical believers in "induction.."

Popper responds in this volume in two ways:

(1) The above research program of Logical Positivism is based on a radical misunderstanding of the nature of possible human knowledge. All human knowledge of general laws (aka causation) rests upon postulating hypotheses and testing these hypotheses. The most humans can ever know, is thus, negative propositions such as "Not all X are Y" . No matter how many X one observes, one is never justified in claiming that "All X are Y." There is, in short, no "logic of induction," that allows us to "build up" general laws from particular observations. .

(2) While there is not clearly some "demarcation principle" between science and non-science, if there were, that principle would be falsification, not verification. This is in contradiction to the Vienna Circle's attempt to divide all propositions into "empirical" and "metaphysical" on the basis of whether the proposition can be "reduced to" a string of observations.

Finally, Popper examines the status of probability statements, when certain statements are not possible, and offers a theory of probabilistic truths that mirrors his previous arguments.

Contrary to one of the other reviews here, this book is not a difficult read. It is written in short clear sentences. It does, however, require attention so that one follows the argument. Some grounding in the history of science would also be helpful. ( )