We should be thankful for every serious attempt to criticize our positions. Praise is of no intellectual value. Victories in debates are of no intellectual value. Yet if we can succeed even in getting a little clearer about our problems, we should be very happy with that intellectual achievement. 
Tag: rational discussion
[Democracy] has the role of enabling us to change our political regime by means of elections, rather than by violence. Tis seems to me of the greatest importance; but it is also miportant that we see how limited it is in its consequences. Some control will be exercised over politicians by such means, assuming that the wish to continue in office. But it is a very blunt weapon, considering the way in which we can exercise preferences only for bundles of political goods. Further, it is also ripe for manipulation – by politicians who find ways to bribe us with money taken from our own pockets, and by their advertising agents, who, as in the United States, have found was to present political issues on television through the use of images in ways which make rational discussion almost impossible. 
Rationality, for Popper, is to be identified with openness to criticism; and each individual is to be valued a s a source of possible criticism. Objectivity, rather than being regarded as the attribute of the particular, wise individual is regarded as a social product – a product of critical discussion. 
It is most important to see that a critical discussion always deals with more than one theory at a time. For in trying to assess the merits or demerits even of one theory, it always must try to judge whether the theory in question is an advance: whether it explains things that we have been unable to explain so far – that is to say, with the help of older theories. 
We start, I say, with a problem – a difficulty. It is perhaps a practical problem, or a theoretical problem. Whatever it may be, when we first encounter the problem we cannot, obviously, know much about it. At best, we have only a vague idea what our problem really consists of. How, then, can we produce an adequate solution? Obviously, we cannot. We must first get better acquainted with the problem. But how?
My answer is very simple: by producing a very inadequate solution, and by criticizing this inadequate solution. Only in this way can we come to understand the problem. For to understand a problem means to understand why it is not easily soluble – why the more obvious solutions do not work. We must therefore produce these obvious solutions and try to find out why they will not do. In this way, we become acquainted with the problem. And in this way we may proceed from bad solutions to slightly better ones – provided always that we have the ability to guess again. [97-8]
The tension between our knowledge and our ignorance is decisive for the growth of knowledge. It inspires the advance of knowledge, and it determines its ever-moving frontiers.
The word ‘problem’ is only another name for this tension or rather, a name denoting various concrete instances of it.
As I suggested above, a problem arises, grows, and becomes significant through our failures to solve it. Or to put it another way, the only way of getting to know a problem is to learn from our mistakes.
This applies to pre-scientific knowledge and to scientific knowledge.
My view of the method of science is, very simply, that it systematizes the pre-scientific method of learning from our mistakes. It does so by the device called critical discussion.
My whole view of scientific method may be summed up by saying that it consists of these three steps:
1. We stumble over some problem.
2. We try to solve it, for example by proposing some theory.
3. We learn from our mistakes, especially from those brought home to us by the critical discussion of our tentative solutions – a discussion which tends to lead to new problems.
Or in three words: problems – theories – criticism.
I believe that in these three words the whole procedure of rational science may be summed up. [100-1]
Before quitting the subject of freedom of opinion, it is fit to take some notice of those who say, that the free expression of all opinions should be permitted, on condition that the manner be temperate, and do not pass the bounds of fair discussion. Much might be said on the impossibility of fixing where these supposed bounds are to be placed; for if the test be offence to those whose opinion is attacked, I think experience testifies that this offence is given whenever the attack is telling and powerful, and that every opponent who pushes them hard, and whom they find it difficult to answer, appears to them, if he shows any strong feeling on the subject, an intemperate opponent. But this, though an important consideration in a practical point of view, merges in a more fundamental objection. Undoubtedly the manner of asserting an opinion, even though it be a true one, may be very objectionable, and may justly incur severe censure. But the principal offences of the kind are such as it is mostly impossible, unless by accidental self-betrayal, to bring home to conviction. The gravest of them is, to argue sophistically, to suppress facts or arguments, to misstate the elements of the case, or misrepresent the opposite opinion. But all this, even to the most aggravated degree, is so continually done in perfect good faith, by persons who are not considered, and in many other respects may not deserve to be considered, ignorant or incompetent, that it is rarely possible on adequate grounds conscientiously to stamp the misrepresentation as morally culpable; and still less could law presume to interfere with this kind of controversial misconduct. With regard to what is commonly meant by intemperate discussion, namely invective, sarcasm, personality, and the like, the denunciation of these weapons would deserve more sympathy if it were ever proposed to interdict them equally to both sides; but it is only desired to restrain the employment of them against the prevailing opinion: against the unprevailing they may not only be used without general disapproval, but will be likely to obtain for him who uses them the praise of honest zeal and righteous indignation. Yet whatever mischief arises from their use, is greatest when they are employed against the comparatively defenceless; and whatever unfair advantage can be derived by any opinion from this mode of asserting it, accrues almost exclusively to received opinions. The worst offence of this kind which can be committed by a polemic, is to stigmatise those who hold the contrary opinion as bad and immoral men. To calumny of this sort, those who hold any unpopular opinion are peculiarly exposed, because they are in general few and uninfluential, and nobody but themselves feel much interest in seeing justice done them; but this weapon is, from the nature of the case, denied to those who attack a prevailing opinion: they can neither use it with safety to themselves, nor, if they could, would it do anything but recoil on their own cause. In general, opinions contrary to those commonly received can only obtain a hearing by studied moderation of language, and the most cautious avoidance of unnecessary offence, from which they hardly ever deviate even in a slight degree without losing ground: while unmeasured vituperation employed on the side of the prevailing opinion, really does deter people from professing contrary opinions, and from listening to those who profess them. [ch. II, 68-9]
We have now recognised the necessity to the mental well-being of mankind (on which all their other well-being depends) of freedom of opinion, and freedom of the expression of opinion, on four distinct grounds; which we will now briefly recapitulate.
First, if any opinion is compelled to silence, that opinion may, for aught we can certainly know, be true. To deny this is to assume our own infallibility.
Secondly, though the silenced opinion be an error, it may, and very commonly does, contain a portion of truth; and since the general or prevailing opinion on any subject is rarely or never the whole truth, it is only by the collision of adverse opinions, that the remainder of the truth has any chance of being supplied.
Thirdly, even if the received opinion be not only true, but the whole truth; unless it is suffered to be, and actually is, vigorously and earnestly contested, it will, by most of those who receive it, be held in the manner of a prejudice, with little comprehension or feeling of its rational grounds. And not only this, but, fourthly, the meaning of the doctrine itself will be in danger of being lost, or enfeebled, and deprived of its vital effect on the character and conduct: the dogma becoming a mere formal profession, inefficacious for good, but cumbering the ground, and preventing the growth of any real and heartfelt conviction, from reason or personal experience. [ch. II, 67-8]
It is the fashion of the present time to disparage negative logic—that which points out weaknesses in theory or errors in practice, without establishing positive truths. Such negative criticism would indeed be poor enough as an ultimate result; but as a means to attaining any positive knowledge or conviction worthy the name, it cannot be valued too highly; and until people are again systematically trained to it, there will be few great thinkers, and a low general average of intellect, in any but the mathematical and physical departments of speculation. On any other subject no one’s opinions deserve the name of knowledge, except so far as he has either had forced upon him by others, or gone through of himself, the same mental process which would have been required of him in carrying on an active controversy with opponents. That, therefore, which when absent, it is so indispensable, but so difficult, to create, how worse than absurd is it to forego, when spontaneously offering itself! If there are any persons who contest a received opinion, or who will do so if law or opinion will let them, let us thank them for it, open our minds to listen to them, and rejoice that there is some one to do for us what we otherwise ought, if we have any regard for either the certainty or the vitality of our convictions, to do with much greater labour for ourselves. [ch. II, 57-8]
Sechste These (Hauptthese):
a) Die Methode der Sozialwissenschaften wie auch die der Naturwissenschaften besteht darin, Lösungsversuche für ihre Probleme – die Probleme, von denen sie ausgeht – auszuprobieren.
Lösungen werden vorgeschlagen und kritisiert. Wenn ein Lösungsversuch der sachlichen Kritik nicht zugänglich ist, so wird er eben deshalb als unwissenschaftlich ausgeschaltet, wenn auch vielleicht nur vorläufig.
b) Wenn er einer sachlichen Kritik zugänglich ist, dann versuchen wir, ihn zu widerlegen; denn alle Kritkk besteht in Widerlegungsversuchen.
c) Wenn ein Lösungsversuch durch unsere Kritik widerlegt wird, so versuchen wir es mit einem anderen.
d) Wenn er der Kritik standhält, dann akzeptieren wir ihn vorläufig; und zwar akzeptieren wir ihn vor allem als würdig, weiter diskutiert und kritisiert zu werden.
e) Die Methode der Wissenschaft ist also die des tentativen Lösungsversuches (oder Einfalls), der von der schärfsten Kritik kontrolliert wird. Es ist eine kritische Fortbildung der Methode des Versuchs und Irrtums („trial and error“).
f) Die sogenannte Objektivität der Wissenschaft besteht in der Objektivität der kritische Methode; das heißt aber vor allem darin, daß keine Theorie von der Kritik befreit ist, und auch darin, daß die logischen Hilfmittel der Kritik – die Kategorie des logischen Widerspruchs – objektiv sind.