1. No Enlightenment without a consistent epistemology
In what is perhaps the most well-known phrase characterising the Enlightenment, Kant admonishes us who aspire to an enlightened attitude to “dare to use your own minds”, i.e. to think for ourselves. The “immaturity” he speaks of is the inability to do just that. And this inability, says Kant, is self-incurred—by which he means: our own fault—if it is not due to a lack of intelligence but to a lack of courage and determination not to simply rely on other people’s thinking and opinions for their own.
Shorter Kant: Don’t rely on any authority if you want to think for yourself! Which, in fact, is a theme that runs through all strands of the Enlightenment, as e.g. Porter points out: “Diderot and d’Alembert’s Encyclopédie thus defined the philosophe as one who ‘trampling on prejudice, tradition, universal consent, authority, in a word, all that enslaves most minds, dares to think for himself’”. Deutsch expands on that thought: “one thing that all conceptions of the Enlightenment agree on is that it was a rebellion, and specifically a rebellion against authority in regard to knowledge.”
But how is this rejection of authority to be accomplished? Rejecting this or that authority had, of course, always been possible; as Deutsch explains: “Authorities have been rejected many times in history, and only rarely has any lasting good come of it. The usual sequel has merely been that new authorities replaced the old.” Even worse: the new authorities might be just as bad in the way they assumed infallibility as any of the old ones.
In their Dialectics of Enlightenment, the German philosophers Horkheimer and Adorno have argued that it was thus no accident that reason so often went hand-in-glove with ‘absolutism’. For reason and science, far from promoting liberty, encourage an absolutist cast of mind, by assuming an ‘absolute’ distinction between true and false, right and wrong, rather than a pluralist diversity of values.
Horkheimer and Adorno themselves worried that such a position of authority was exactly what Enlightenment thinkers had in mind: “Enlightenment, understood in the widest sense as the advance of thought, has always aimed at liberating human beings from fear and installing them as masters.” With the disasters of the Holocaust and World War II still being felt acutely, they gloomily sum up the main point of their book: “the wholly enlightened earth is radiant with triumphant calamity.”
What Horkheimer and Adorno imagine to have discovered is an inevitable development—a “lapse from enlightenment into positivism”. This “positivism”, which they take to be synonymous with rationality, in their mind has one particular goal: “the acquiescence of thought to the production of unanimity”. Their conclusion, finally, is a stark indictment: “Enlightenment is totalitarian.”
In defence of Horkheimer and Adorno, it has to be said that, if their premises regarding rationality were correct, their conclusion would make sense. And they are hardly alone in thinking that rationality aims at finding one, and only one, “correct answer” to every question—or in other words: finding absolutely true statements. How easily a belief in having found such answers translates into authoritarian attempts to impose that truth on others hardly needs spelling out.
To anyone with even a passing acquaintance with Popper’s philosophy, however, Horkheimer and Adorno’s premises not only look a little suspect, they are just glaringly wrong. First, in their protrayal of positivism and science, they make what should be an embarrassing mistake to anyone purporting to do serious philosophy, a mistake Popper later damningly criticised with respect to people accusing him of “scientism”: “they themselves seem to accept, implicitly and uncritically, that positivism or scientism is the only philosophy appropriate to the natural sciences.” Second, they seem to be unaware that Popper, more than a decade earlier, had devised an epistemology that offered a consistent alternative to classical rationalism and its justificationism—a critical rationalism that stressed the ideas of fallibility and progress, abandoning the former ideal of the search for certain truth. Popper’s newly conceived concepts of “truth”, “knowledge”, “objectivity”, and “progress” in effect rendered criticism like that of Horkheimer and Adorno obsolete.
An answer along essentially critically rational lines to the question raised at the beginning of this section had, incidentally, already occurred to John Stuart Mill—just as much a champion of the Enlightenment as Popper—who identified the only characteristic that can make one’s opinion rational: one’s having followed a critical process in arriving at it.
No wise man ever acquired his wisdom in any mode but this; nor is it in the nature of human intellect to become wise in any other manner. The steady habit of correcting and completing his own opinion by collating it with those of others, so far from causing doubt and hesitation in carrying it into practice, is the only stable foundation for a just reliance on it: for, being cognisant of all that can, at least obviously, be said against him, and having taken up his position against all gainsayers—knowing that he has sought for objections and difficulties, instead of avoiding them, and has shut out no light which can be thrown upon the subject from any quarter—he has a right to think his judgment better than that of any person, or any multitude, who have not gone through a similar process.
But it was Popper who systematized these ideas into a coherent whole. Without ever saying so, and perhaps without realising it, Popper thus gave us the missing link that could actually make the Enlightenment be capable of pursuing its central aim.
2. Popper’s solution
The guiding question in Popper’s epistemology is, ‘How can we learn from experience?’—given that any form of induction is logically invalid and thus cannot lead to knowledge. His answer stems directly from the rejection of certain knowledge as the goal of our intellectual endeavours. Instead, what we can aim for is increasingly better knowledge. And for better knowledge, we only have to be able to make a choice: that between an idea that is a better explanation of some set of phenomena than another idea. And that is where deductive logic comes in, as Notturno explains: “No argument can force us to accept the truth of any belief. But a valid deductive argument can force us to choose between the truth of its conclusion on the one hand and the falsity of its premises on the other.”
In that way, logic can act like a point in a railway track that forces us to choose this or that direction. This is the basis of Popper’s criterion of demarcation between scientific and non-scientific theories: suitably formulated theories have this logical property. But this can only be one part of a scientific methodology; another part has to be a critical attitude that prevents us from sneaking off the track and past the point, onto whatever cow path most appeals to us. This point, specifically that logic is only a necessary, not a sufficient, ingredient in Popper’s methodology, has been consistently overlooked by some of Popper’s most vociferous critics—e.g. Paul Feyerabend, Imre Lakatos, Thomas Kuhn, and (to cite someone a little more contemporary) Susan Haack. Similarly, and contrary to another criticism by Feyerabend, there is no Popperian method; there is a methodology. In fact, Popper explicitly denied he was offering a method in the Preface to Logic: “I do not care what methods a philosopher (or anybody else) may use so long as he has an interesting problem, and so long as he is sincerely trying to solve it.”
To put it in a nutshell: critical rationalism tells us how suitable methods can use logic and experience in the pursuit of progress in knowledge.
Falsificationism—Popper’s methodology based on falsifiability, fallibilism, a critical attitude, and the rejection of the “idol of certainty” — only makes sense within this whole framework of assumptions. Falsifiability (i.e. the logical property of a theory to entail a set of potential falsifiers) isn’t all that counts in Popper’s methodology; neither does finding a falsifier mean the immediate falsification of a theory. Falsificationism is just as much about the critical attitude that makes use of a theory’s logical form (its falsifiability) in order to achieve progress. This progress, however, can only be achieved by critically testing the theory, i.e. putting it in danger of being falsified. Falsification, in turn, entails not just finding a falsifier but ideally also the existence of a competing theory that is corroborated by that which acted as a falsifier for the first theory—a competing theory, what’s more, that is better than its rival. Thus do we achieve progress in knowledge.
In other words: falsificationism never achieves certain knowledge, it doesn’t suppose that there is such a thing as manifest truth, let alone truth that is inferrable from facts alone, it doesn’t just collect facts but uses facts to test ideas, it uses logic, and is bound together by a pervasive critical attitude.
3. Fixing ‘truth’ and ‘objectivity’
One hurdle in Popper’s philosophy, however, that we have to get out of the way if we want to realise the Enlightenment’s full potential is his concept of absolute truth. Popper himself cites two main reasons for sticking with absolute truth: such a concept, he says, helps guard against authoritarianism because its premise is that “truth is beyond human authority”; and it is supposed to ward off what Popper (in line with common but, as I’ll argue, misleading usage) calls “relativism”: the unfortunate “view that there is no absolute or objective truth, but one truth for the Greeks, another for the Egyptians”.
Now, Popper sees very clearly that there is a danger attached to using a concept of absolute truth: “The idea of a philosophical absolutism is rightly repugnant to many people since it is, as a rule, combined with a dogmatic and authoritarian claim to possess the truth, or a criterion of truth.” Rather surprisingly, though, he brushes that danger aside because, he says, a fallibilistic attitude is all that is needed to defuse that situation: “This kind of absolutism is completely free from any taint of authoritarianism.”
Strange as it seems to court danger in that way, one would suppose that Popper had a good reason to insist that truth is absolute. But the fact is that pretty much the only argument for that view that is apparent in his writing is that if truth is correspondence with facts, and facts are absolute, then so is truth. Apart from that, he always uses ‘absolute’ and ‘objective’ interchangeably with respect to ‘truth’. But surely we wouldn’t want to imply that there is no difference to be made between those terms that doesn’t only make sense but is actually actively helpful. Couple this with Popper’s second reason to insist on absolute truth—“relativism”—and you can see why ‘absolute’ is the wrong concept to use. The reason is that we must prevent people from thinking that “I have my truth, you have yours” is a reasonable idea if we want to be able to discuss things critically. But that danger is actually one of subjectivism; and what we want is that truth be objective. (More on objectivity below.)
As it happens, there is also a positive reason to stop using the concept of ‘absolute truth’: truth is always relative. Consider the canonical example of a statement that is considered to be absolutely true, also cited by Popper as such: “2 + 2 = 4”. This statement is rather obviously relative to certain assumptions, or premises: that we are, for example, using a base-10 number system and not base-3; that the ‘+’ operator means exactly one thing; the axioms concerning natural numbers; and so on. And this is actually no problem whatsoever: within those assumptions the statement remains objectively true. While there is no sensible way in which we can say that it is absolutely true, all the characteristics we insist a statement have in order to be capable of being discussed critically are captured by its being objective. Nothing is gained—and all is, if not lost, endangered—by calling it ‘absolute’.
Important intuitions about the concept of ‘truth’ would remain intact if we give up the idea of absoluteness. Popper, for example, stresses the importance of truth’s timelessness; that would be entirely untouched, since any premises of an objective statement are constituents of a logical system and are, as such, timeless. An added advantage, in fact, would be the necessity on the part of a person making a truth claim of being able to give that claim’s truth conditions—so that one would have to actively and explicitly undermine any possibility of claiming any kind of authority based on the truth of the statement in question.
What is more, a relative concept of truth could put another term that is of crucial importance in Popper’s work front and center: the term ‘problem’. Popper himself pointed out that some of our intuitions about ‘truth’ have always implied a relative concept of truth: “When the judge tells a witness that he should speak ‘The truth, the whole truth, and nothing but the truth’, then what he looks for is as much of the relevant truth as the witness may be able to offer.” And not just that: we are looking for statements in relation to certain problems:
Mere truth is not enough; what we look for are answers to our problems.
Only if it is an answer to a problem – a difficult, a fertile problem, a problem of some depth – does a truth, or a conjecture about the truth, become relevant to science. This is so in pure mathematics, and it is so in the natural sciences. And in the latter, we have something like a logical measure of the depth or significance of the problem in the increase of logical improbability or explanatory power of the proposed new answer, as compared with the best theory or conjecture previously proposed in the field.
This quote also presents an obvious solution to Popper’s largely unsuccessful attempts to formally define his idea of verisimilitude, or getting nearer to the truth, which was predicated on an absolute concept of truth. Here, Popper himself offers a worthy alternative to an increase in verisimilitude as the aim of science: an increase in the depth and significance of our problems and our proposed solutions. It is not a coincidence that this chimes perfectly with the way that Popper (in Logic, no less) characterised the progress of science as one that is fundamentally relative to problems: “[Science’s] advance is, rather, towards an infinite yet attainable aim: that of ever discovering new, deeper, and more general problems”.
A possible way to put this problem-relative concept of truth into a definition would be: A statement is true if and only if the implications it entails which are relevant to the problem the statement addresses correspond to the relevant facts.
Such a problem-relative concept of truth would lead to another term becoming more consistent: that of ‘proof’. Popper thought proof was only to be had in the supposedly exact sciences: “nothing can be justified or proved (outside of mathematics and logic)”. But who said ‘proof’ has to be understood within a framework of absolute truth and certain knowledge? In fact, within a problem-relative framework, it makes sense to take this statement by Notturno: “Our so-
The second term of central importance in this regard is that of ‘objectivity’. While in his early Logic Popper simply said that “the objectivity of scientific statements lies in the fact that they can be inter-subjectively tested”, he fleshes out the concept of objectivity in his epistemological magnum opus, Objective Knowledge, using the idea of Worlds 1 to 3 for the physical world, the world of states of mind, and the world of objective contents of thought, respectively.
Popper’s theory of knowledge was conceived explicitly as a safeguard against subjectivism. The traditional conception of ‘knowledge’ was, from Popper’s point of view, fatally flawed: “I regard the commonsense theory of knowledge as a subjectivist blunder.” Take the generally accepted definition of ‘knowledge’ as ‘true justified belief’: right off the bat, and ignoring all the (sometimes devastating) criticisms that have been made against that definition, this says that knowledge is supposed to be a species of belief, i.e. it is supposed to be something explicitly subjective. To which Popper says: This won’t do.
A corollary of the common-sense theory of knowledge is the idea, that “there is nothing in our intellect which has not entered it through the senses“. Apart from the fact that we know nowadays that our senses are anything but reliable, this concept runs into the same problem as any other kind of justificationism—a problem for which Hans Albert coined the term ”Munchausen trilemma”.
Against both of these parts of the tradition definition of ‘knowledge’, Popper puts his idea of a World 3 of objective contents of thought. For Popper, who called himself a dualist (in The Self and Its Brain), his three worlds are ontologically separate, which led him to assert that World 3 objects did not only have autonomous characteristics but also an autonomous existence. Both of those assumption are, in fact, neither helpful nor necessary.
As to the first of those assumptions, Popper himself introduces an important caveat: “should [mental states] one day be reduced to physical states, then this will be a tremendous success”. And this would, in fact, not disturb his theory in the least: World 2 could be viewed simply as a subset of World 1. Similarly, World 3 could be viewed simply as a subset of World 2: those mental states that are objective, i.e. that have autonomous properties and are thus of particular interest if we want to study how there can be progress in knowledge.
As to the second assumption, Popper devises a thought experiment to argue for the independent existence of World 3. In a post-apocalyptic world, after all our machines, tools, and knowledge of how to use them have been destroyed but not our libraries, civilization might soon get started again; without libraries, not so much. Popper mistakenly thinks this is decisive; but, in the words of Gadenne: “This, however, does not follow from the premises of the thought experiment. Strictly speaking, this thought experiment only demonstrates the significance of books.”
What remains of Popper’s World 3 is still of considerable interest and is, in fact, all that his argument for the possibility of ‘objective knowledge’ ever required: it is the realisation that in order for objective knowledge to be had with respect to a certain problem, the only requirement is that there be World 3 objects there to characterise and critically discuss.
Finally, let’s a consider a question Popper poses in Objective Knowledge: “What is the characteristic difference between a scientific theory and a work of fiction?” What Popper here refers to is the most basic question we can ask with regard to any human endeavour: What is the aim that we are pursuing? Or in Popper’s words: “The difference is, I suggest, is that the theory and the story are embedded in different critical traditions. They are meant to be judged by quite different traditional standards”. The aim we pursue sets the boundaries within which a discussion can take place; and if within those boundaries there should happen to abide some World 3 objects, then it is possible to attain objective knowledge of them and to find objectively true statements.
This too was anticipated by Mill, who laid out the argument, as if it were the most obvious thing in the world, that of course anything that can be rationally discussed is, for all intents and purposes, amenable to “proof”:
There is a larger meaning of the word proof, in which this question is as amenable to it as any other of the disputed questions of philosophy. The subject is within the cognizance of the rational faculty; and neither does that faculty deal with it solely in the way of intuition. Considerations may be presented capable of determining the intellect either to give or withhold its assent to the doctrine; and this is equivalent to proof.
4. The reach of a critically rational New Enlightenment
It is already in the Introduction to Logic that Popper says, in effect, that any domain in which we could want to obtain knowledge is amenable to his critical rationalist methodology:
And yet, I am quite ready to admit that there is a method which might be described as ‘the one method of philosophy’. But it is not characteristic of philosophy alone; it is, rather, the one method of all rational discussion, and therefore of the natural sciences as well as of philosophy. The method I have in mind is that of stating one’s problem clearly and of examining its various proposed solutions critically.
In his Open Society, he further specifies this idea when he says about the book: “It further tries to examine the application of the critical and rational methods of science to the problems of the open society.” Albert, pushing the idea even further, put it with characteristic bluntness: “The method of critical testing is actually not confined to any intellectual or social domain.” And even more specifically: It would be simply fallacious to believe “that the domain of ethics, of values and norms, is exempt from critically rational analysis”.
It goes without saying that any such ideas will be met with cries of “scientism!” But that charge—or that “all-purpose, wild-card smear”, as Dennett calls it—can be safely ignored as it is, out of ignorance of Popperian philosophy, unfailingly used “for the aping of what is widely mistaken for the method of science”.
The accusation of “scientism” is especially popular in the social sciences, and Popper himself was accused of it in the (utterly misleadingly) so-called “positivism dispute” in Germany in 1961. His above-cited defence is as pertinent today as it was when he wrote it: If only the critics would understand that induction is invalid, that no science could possibly use it, and that every science has to use a critical methodology, then we could stop wasting our time talking about this nonsense.
This is surprisingly relevant to what has come to be known as the “replication crisis” in the social sciences. Seemingly out of the blue, a 2005 paper by Ioannidis about “Why most published research findings are false” claimed that certain statistical methods (above all null-hypothesis significance tests) were bound to give results that could be wrong in as much as half of all cases. In fact, this claim wasn’t entirely new; the sociologist Paul Meehl had said much the same thing in a paper in … 1967. Except that Meehl actually knew what the problem was—as he formulated it three decades later: “The problem is epistemology, not statistics”. A 2017 paper by Peter Holtz and me tries to explain in some more detail how a proper understanding of Popperian epistemology could help the social sciences find a way out of thicket they seem to be in.
A critically rational analysis of the replication crisis and related social-science woes would have to concentrate on the actual use of statistical methods. It is entirely commonplace in these disciplines to assume that the point of a NHST is, for example, to reject the null hypothesis, the find a suitably high “positive predictive value”, “to improve the post-study probability”, to use a “straw-man” null hypothesis the better to achieve a significant result, or to “answer a researcher’s real question: what are the odds that a hypothesis is correct?” The utter naiveté with regard to epistemology is perhaps best expressed by Colquhoun, who confidently asserts:
The problem of induction was solved, in principle, by the Reverend Thomas Bayes in the middle of the 18th century. He showed how to convert the probability of the observations given a hypothesis (the deductive problem) to what we actually want, the probability that the hypothesis is true given some observations (the inductive problem).
As hilariously wrong as this is, it is probably pretty instructive to realise that even highly trained academics are utterly ignorant about something as fundamental to epistemology (and thus to science) as the problem of induction. With just as much misplaced confidence, Colquhoun goes on to dispel any doubts that might have lingered as to his grasp of how science works:
Science is an exercise in inductive reasoning: we are making observations and trying to infer general rules from them. Induction can never be certain. In contrast, deductive reasoning is easier: you deduce what you would expect to observe if some general rule were true and then compare it with what you actually see. The problem is that, for a scientist, deductive arguments don’t directly answer the question that you want to ask.
Ironically enough, the inventor of NHSTs, R. A. Fisher, actually not only specifically warned against misusing the term ‘significance’ and misinterpreting p-values, he in fact even just as specifically pointed out the asymmetry between verification and falsification on the one hand and how deductive logic may be used on the other:
In relation to any experiment we may speak of this hypothesis as the “null hypothesis,” and it should be noted that the null hypothesis is never proved or established, but is possibly disproved, in the course of experimentation. Every experiment may be said to exist only in order to give the facts a chance of disproving the null hypothesis.
It might be argued that if an experiment can disprove the hypothesis that the subject possesses no sensory discrimination between two different sorts of object, it must therefore be able to prove the opposite hypothesis, that she can make some such discrimination. But this last hypothesis, however reasonable or true it may be, is ineligible as a null hypothesis to be tested by experiment, because it is inexact. If it were asserted that the subject would never be wrong in her judgements we should again have an exact hypothesis, and it is easy to see that this hypothesis could be disproved by a single failure, but could never be proved by any finite amount of experimentation.
While applying a critical rationalism equally to all the different branches of science should arguably be uncontroversial, it is sure to raise eyebrows for a somewhat different reason if applied to what Popper called “the problems of the open society”. This explicit aim of The Open Society and Its Enemies, and Popper really leaves no room for misinterpretation here, means nothing less than “the introduction of scientific method into politics”.
To be fair, Popper says precious little about the question what an open society actually is. And what he does say is certainly suggestive but is also in urgent need of being unpacked and put in some proper context. Right in the introduction, Popper states that “the open society…sets free the critical powers of man”; later in the book, he adds that “the society in which individuals are confronted with personal decisions [is] the open society”.
If that sounds just a bit like Kant’s admonishment to think for yourself, that’s because Popper explicitly saw The Open Society as championing, if possible improving upon, Enlightenment values:
It is the longing of uncounted unknown men to free themselves and their minds from the tutelage of authority and prejudice. It is their attempt to build up an open society which rejects the absolute authority of the merely established and the merely traditional while trying to preserve, to develop, and to establish traditions, old or new, that measure up to their standards of freedom, of humaneness, and of rational criticism.
The first thing we have to understand about an open society is that it is not synonymous with ‘democracy’, and that it is specifically opposed to any kind of majoritarianism—which, in fact, is a form of justificationism and runs into the same logical inconsistencies as any other. This thought leads Popper to give ‘democracy’ what we might call a critical definition:
And indeed, it is not difficult to show that a theory of democratic control can be developed which is free of the paradox of sovereignty. The theory I have in mind is one which does not proceed, as it were, from a doctrine of the intrinsic goodness or righteousness of a majority rule, but rather from the baseness of tyranny; or more precisely, it rests upon the decision, or upon the adoption of the proposal, to avoid and to resist tyranny.
… [Democracy] consists of governments of which we can get rid without bloodshed—for example, by way of general elections; that is to say, the social institutions provide means by which the rulers may be dismissed by the ruled, and the social traditions ensure that these institutions will not easily be destroyed by those who are in power.
Summing up the core of Popper’s theory of democracy, Jarvie focuses on another important feature of The Open Society: “While providing no guarantee of freedom and openness, this was the best available insurance against their erosion.” Far from being some impersonal process that might perhaps be stanched by suitably constructed institutions, this erosion is what Popper identified to be an inevitable, actively orchestrated danger: “the perennial attack on freedom and reason”.
Returning to Popper’s assertion that the open society “sets free the critical faculties of man”—which would be the faculties under “perennial attack”—one way to further specify what Popper can have meant by that readily presents itself if we consider what is entailed by his epistemology:
…objectivity is closely bound up with the social aspect of scientific method, with the fact that science and scientific objectivity do not (and cannot) result from the attempts of an individual scientist to be ‘objective’, but from the friendly-hostile co-operation of many scientists… .
And this is the thought that led Jarvie to the realisation encapsulated in his book’s title: “From this effort we can extrapolate his view that science is a model for society: science is the knowledge-gaining institution par excellence.” It is, then, not our individual critical faculties that an open society sets free but mankind’s. An open society’s institutions would have to enable and unwaveringly foster all the elements necessary for critical reason to flourish. This immediately suggests what would have to be among the principal aims of institutions such as an education system and a free press.
The second characteristic of an open society Popper mentions is that it is where people “confronted with personal decisions”. What Popper means is ‘personal’ in contradistinction to ‘determined by the society’. These decisions are not about what to have for lunch but the kind of “far-reaching decisions for which we are morally responsible”. The relevant distinction here is, in fact, between subjective and objective questions—and Popper is talking about the latter, those which can become “objects of critical consideration”.
The kind of freedom that an open society makes possible is neither God-given nor inevitable; we have to make a decision to actually want it—and defend it. We have to decide what we want the aim of such a society to be. The society itself and its institutions then become means to an end—as Notturno remarks, ending with a realisation that might be of interest to would-be regime changers around the world:
Popper did not regard socialism or capitalism or any economic system as an end in itself. He thought that such systems are to be valued—and evaluated—primarily as means toward freedom. The same holds true for political systems. Even democracy should be valued as a means to another end. It may well help us to preserve freedom, but it can never create freedom if we ourselves do not care for it.
In conclusion, once the aims of a society have been decided upon, there are objective questions to be discussed and objective knowledge to be had. A critically rational politics, such as Popper said was the goal of The Open Society to explore, would and could work straight along the lines traced out by Popper’s scientific methodology:
- Characterising a problem of public interest, giving specifics as to a) what factual state of affairs b) violates which societal ideal c) for which specific reasons.
- Specify the conditions that any proposed solution would have to satisfy.
- Give a detailed proposal for a solution, citing both its specific problem-solving characteristics and possible drawbacks that might lead to new problems.
- Critically test suitable proposed solutions.
This could give life to Popper’s somewhat anaemic term “piecemeal engineering”, which he introduced as a contrast to a dangerous form of utopian, or wholesale, engineering of a complete society from scratch. Figuring out what still qualifies as piecemeal engineering has long been a question without much of a satisfactory answer. Jarvie, however, offers a valuable insight in this regard:
One obvious difference between the piecemeal and the wholesale is that the piecemeal engineer considers possible unintended consequences of any change carefully and in advance of the change, trying to devise criteria whereby the success or failure of the change can be estimated.
In a nutshell, how do we apply the “methods of science to the problems of the open society”? In the words of David Deutsch:
How can we formulate policies for the unknown? If we cannot derive them from our best existing knowledge, or from dogmatic rules of thumb like blind optimism or pessimism, where can we derive them from? Like scientific theories, policies cannot be derived from anything. They are conjectures. And we should choose between them not on the basis of their origin, but according to how good they are as explanations… .
This way of putting it offers a seamless transition to another area that could benefit hugely from a specifically critically rational perspective—an area that has been plagued for centuries by the kind of thinking just denounced by Deutsch: that of ethics, where the is–ought pseudo-problem continues to cloud philosophers’ minds to this day.
[To be expanded and updated.]