Table of contents
Chapter 8. knowledge scientific, I: Reliability of Science
N. López Moratalla
Physical reality, the universe, has a rational order, a "logic" which is natural, i.e. not given by man, unlike that possessed by the artifices constructed by man. This natural rationality of the physical world can be known by human intelligence; that is, it is offered to the human knowledge and allows him to form an idea about it, when the idea he has formed corresponds to reality he reaches a knowledge which is true.
One way to enter into a relationship with reality is experience: a direct contact mainly through sensory perception. Man observes nature and acquires a series of data, information, which is offered to him immediately and directly; other data are obtained with the help of financial aid of instruments that amplify the range of his senses. He can also experiment, provoke new situations in relation to natural processes, and by observing the responses that nature gives him, he obtains other information beyond that obtained by mere observation. The methodology of the experimental sciences makes it possible to reach an explanation of reality, or more precisely of some aspects of reality; with the information thus obtained, theories are constructed that must be contrasted, subjecting them to the control of experimentation. Theories are not a direct reflection of reality; they are rather an abstract framework, a network of models; they are an invented construction. On the other hand, experimentation is, in addition to source of information, the way to verify the validity of knowledge. Scientific truth is therefore the correspondence between natural realities and the scientific theories that explain how they are.
Experimental sciences make it possible to reach a reliable knowledge of a specific area of physical reality and therefore, like everything else knowledge, they are properly a human good and an integral part of culture. Science has value: it is a human good, regardless of whether or not its findings directly lead to technical applications. The proper meaning of science is not linked to the power and capacity to dominate that scientific knowledge inherently engenders.
However, Science, theoretical scientific knowledge, does not always appear as such a good; there are even those who have a certain difficulty in admitting or respecting scientific truth. As we will see later, some deny the possibility of attaining some truths, reducing scientific knowledge to mere conjecture, without any possibility of establishing with certainty whether or not there is a connection between a theory and the theorised reality; others reduce its significance exclusively to the usefulness of the application of its findings; there are even those who maintain that scientific truth is conventional, mere agreement among scientists, while others attribute to Science the consideration of the only rigorous knowledge.
b) Science and truth
If scientific theories are constructions and not the direct reflection of reality, can we affirm that with scientific methodology we reach truths? How can we be sure that a model agrees with reality? This is a fundamental question, and the affirmative answer to these questions already opened a strong controversy precisely when this method began; at the moment when Galileo, trying to prove the hypothesis that the Earth revolves around the sun, built a telescope to see the stars, and at that moment he adopted the new way of reasoning: truth is reached by contrasting hypotheses with experimentation.
The question of what truth we achieve with science, what reliability scientific methodology has, is at final an ethical question. It should be noted that there is not only an ethics of morals, but also an ethics of knowledge. The Ethics of knowledge consists of an objective understanding of where status one finds oneself in terms of truth. An ethical reflection on the scope and limits, on the meaning of the methodology of the experimental sciences is therefore required.
A first aspect to bear in mind, when it comes to evaluating the cultivation of certain sciences from a deontological point of view, is that science cannot be done unless it is based on the selection of data, on abstracting a series of aspects from reality1. There is no scientific work if reality is not simplified, because it is not possible to establish a general system of the entire universe that captures the structure of the whole of reality; models, the search for a representation, always involves simplifying: there is no strict parallelism with reality that exhausts all its aspects and takes it into account in its totality. This simplification means that many aspects cannot be taken into consideration, i.e. that the physical world always transcends model: the scientific knowledge does not exhaust reality. It would therefore be unethical to extrapolate scientific knowledge in order to explain aspects of reality that fall outside the scope of experimentation. It would mean reducing reality by pretending that what is necessary to explain a physical phenomenon is sufficient to explain it.
If physical reality transcends model, the sciences can progress and must, in order to do so, abandon models, eliminate certain approaches and test others. In other words, models can be modified. The idea of a definitive status for science is absurd. Scientific theories have, for this reason, a character provisional. A theory, a model is an approximation to reality, which is sufficient as long as it explains or represents the known phenomena, or the chosen aspects of reality; but when the scope of the reality that is studied and that one tries to capture with the model is extended, it must necessarily become more complicated. The progress of science can develop in this sense of enlargement, making the models more complex, thus capturing new aspects; and progress can also take place in the sense of simplification, of simplicity, of elimination of what is superfluous, in order to achieve the smallest issue of postulates, which, because of their more general character, cover the widest possible field. In any case, it would be unethical for a model, a theory, to be imposed as irrevocable, with the character of a dogma closed to modification in the face of new findings. The ethics of the scientific knowledge requires the question of whether the postulates used are sufficiently well established, or whether, on the contrary, they are only a starting point, a mere hypothesis, or even whether they should be rejected.
The validity of the hypotheses
As we have just seen, scientific hypotheses and theories are models, a representation of reality that can be modified. Scientific progress consists, therefore, in getting closer and closer to the goal of a knowledge of the universe. And since the world has an order, a rational coherence, it is possible to achieve proven generalisations; in other words, scientific truth can be attainable.
It is obvious that with the scientific method there is a certain separation from reality; there is a distancing when entering into the framework of the models that represent that reality. As Hannah Arendt2 points out, "scientists formulate their hypotheses in order to trigger their experiments, to test their hypotheses, during all this activity it is clear that they are dealing with a hypothetical nature". And so, as Cardinal Bellarmine pointed out to Galileo, "proving that the hypothesis saves appearances is in no way the same as demonstrating the reality of the Earth's motion". Indeed, showing that the data agrees with a model is not the same as showing that the model agrees with reality.
The scientific method establishes with plenary session of the Executive Council rigour what experimental support a given theory has. "What Galileo did, and what no one had done before, was to employ the telescope in such a way that the secrets of the universe were given to human cognition, - with the certainty of sense perception, - that is, he brought within the reach of the earth-bound creature and his body subject to the senses what had always seemed beyond his grasp, open at most to the insecurities of speculation and imagination..... By "confirming" his predecessors Galileo established demonstrable fact where before there had been inspired speculation."3 And at the same time, by that method - and this was what Galileo was trying to show - one can come to establish that a model, that one worldview is more plausible than another, is a better representation and therefore truer than another. That is, there are criteria for judging the validity of the hypothesis. The criterion of validity is not simply the quantitative accumulation of evidence, but the following criteria4 can be pointed out as criteria: firstly, the explanatory power and the predictive power of the model. A paradigmatic example was the double helix model for the structure of DNA proposed by Watson and Crick in 1953. There was no empirical evidence, but it could be accepted long before conclusive data appeared because it explained the conservation of the genetic message and the fidelity of its transmission by predicting the replication process of this genetic material.
The validity of a theory can also be judged by the accuracy of its predictions, by the convergence of different and mutually independent tests, and also whether it can be used as an explanation of a different realm of physical reality from the one it was intended to be model.
It must be borne in mind that a statement about the validity of a theory is very different if it is based on the direct observation of a process - even if this requires the use of technical instruments - than if it is based on the model representation of an unobservable process. For example, it follows from direct observation that the digestion of a certain sugar is initiated by the enzymes present in saliva; on the other hand, when trying to establish the mechanism according to which its transport across a certain membrane takes place, we can only check the observable consequences of this transport. On the other hand, observable phenomena, the experimental data , are always valid even if they are open to new explanations.
Through these verifications, experimental laws emerge that relate the observed data , that can be demonstrated with a certain approximation Degree and that are always fulfilled under defined conditions. General principles are also constructed, relationships between concepts, which can be verified in terms of their application to specific cases.
It can therefore be affirmed that scientific theories, even when they maintain a hypothetical character, can be judged as to their reliability. In other words, the scientific method makes it possible to attain knowledge of a sphere of reality which, while true, is approximate, and therefore open to modifications that make it more precise; the sciences always have a helical development . At the same time, the experimental sciences have a meaning that goes beyond the mere ability to master the universe that they confer on man, since they allow him a knowledge of the physical world that is true, although limited; they explain the behaviour of this reality and have a certain provisional character.
In this reflection on "scientific truth" it seems necessary to add a brief analysis of two positions that have had - and still have - great influence in the intellectual atmosphere of recent decades: logical positivism and scientific relativism. From both of them, although for very different reasons, the meaning of science as a way of accessing the knowledge of physical reality is obscured.
c) Logical positivism: the unending search for truth
It may be useful - Martínez Doral5 points out - to dwell on the thought of Karl Popper, one of the most famous positivists we have today, in whom there is at the same time a desire to abandon the narrow intellectual atmosphere bequeathed to us by the last century, and to breathe more freely. Popper is a positivist who wants to go beyond positivism. He has not entirely succeeded, but the attempt he makes to get out of it is very interesting and from this effort we can learn some things.
Popper's postulates can be summarised in the following five points:
1. First of all, what he called the critical attitude. The starting point of his theory is a psychological observation that gradually developed over the years: the contrast he thought he observed between the dogmatism of the philosophers he met - Marx and Freud - and the reasonable attitude of scientists. Speaking of Einstein, he says: "I was impressed by Einstein's own clear statement that he would regard his theory as untenable if it did not stand up to certain tests.... Einstein was looking for crucial experiences, whose agreement with his predictions would in no way establish his theory, while a disagreement, as he himself was the first to point out, would show that his theory was untenable. Thus I came to the conclusion that the scientific attitude was the critical attitude that did not seek satisfactory justifications, but crucial contrasts that could disprove the contrasted theory, although it could never establish it".
2. A second postulate is "falsifiability": what is it that fundamentally distinguishes the critical attitude from the dogmatic one? According to Popper it is the acceptance or rejection of falsifiability. Our theories are like nets, with them we create not a real world, but precisely that of our own nets, with which we try to catch the real world. If the conclusions contradict experience, the theory is falsified. If they do not contradict it, it is not thereby affirmed. In other words, Science advances from agreement with a now classic formulation: "by essay and progressive elimination of errors". Theories, he says, can only be refuted negatively and it is not possible to reach definitive truths. "What makes a man of Science is not his possession of the knowledge of irrefutable truth, but his persistent and recklessly critical enquiry into truth".
3. In this attempt to meticulously construct a logic of science, he comes up against topic to distinguish science - "demarcate" it - from other different forms of knowledge (pre-science, pseudo-science and goal-science).
For Popper, there is continuity between the pre-scientific level - that of the man in the street - and the scientific level, because in both the knowledge progresses, noticing and searching for errors. On the contrary, pseudo-science - the cognitive pretension that presents itself with the guarantees of Science, without having submitted to its demands - does not seek crucial contrasts, but justifications. It does not limit itself to presenting its explanations as pure hypotheses, but as scientific laws about individual, psychological or social problems.
The last stage, the goal-science - the reflection on the true nature of being, of reality - is not for Popper pseudo-science, but there is in it a continuous question: is it a guaranteed knowledge , or is it even an indispensable knowledge given the nature of the question it raises? Throughout his intellectual biography there is a desire to give an affirmative answer to this question and, in fact, for a long time he polemicised with the positivism of the Vienna Circle. In this sense, we said that Popper is a positivist who wants to get out of the positivism prevailing in the university of his time, which only recognises as knowledge that obtained by the method of the experimental sciences. For Popper, the meta-scientific knowledge makes sense, it has meaning, but he cannot be sure that it was a safe knowledge because it cannot be contrasted by experience and for this reason he cannot completely free himself from positivism.
4. Popper's followers claim that their master's greatest achievement is to have solved the old problem of induction: how do we get from singular statements to universal theories in science? How do we say that what is valid for the experienced cases, "some", will also be valid for the non-experienced cases, "all"?
His reasoning was along these lines: induction should be discarded as a method in science and replaced by the hypothetico-deductive method. What characterises science are bold hypotheses, statements with a high informative content, networks that always go beyond the available data , and which will be contrasted by experience: hypotheses and deductions.
"A single black swan, we can dismiss the hypothesis that all swans are white; but millions of white swans do not allow us to take it for granted - yes, for probable - that all swans are white". In this "yes for probable" Popper leaves the door open to the possibility of essential induction. What he denies is that logical induction is legitimate: there is no way to establish a rigorous logical connection between the singular and the universal. At this point he takes a stand against positivism and, to some extent, in favour of Metaphysics. Positivism remains an excessively narrow ambit, an excessively narrow fence; and in this sense, it is a very characteristic representative of the current status of scientific thought.
Essential induction is something quite different: it is not passing from some cases to all by generalisation, but by intellectual vision of the essence, although the knowledge of what a thing is is always imperfect. For example: if I know numerically all the triangles that exist and, on the other hand, I do not know the notion of triangle, I have not been able to identify the proper and distinctive characteristic of triangles; but I can define it -although all definitions are always open- if I know the notion.
Popper says: "If there is no order, which is nature, it is possible that tomorrow's universe will behave in a way that refutes the most proven generalisations of today. We are not quite sure that there is such an order and that this order is continuous, that is, that this order extends from the past into the future". But if there is, then essential induction draws its strength from it, and is the foundation of the method of essay and error, of the hypotheses of deduction; if there is, essential induction allows scientific truths to be discovered. Or, to put it another way: the rational coherence of the world, its internal consistency, are data meta-scientific which are and will always be - Popper seems to say - at the internal origin of Science.
5. For Popper, truth is unattainable, it is only the ideal of our research; a "search without end". He does not admit that it is rather an endless meeting , in the sense that the definition that fully captures the whole of reality is not within our reach. Every scientific statement is provisional forever, so that any pretension to reach a truth final would be dogmatic and would have to be replaced by criticism, both in the field of experimental sciences and outside them: certainty is impossible.
There is, however, a change in this respect in Popper's later writings ("Post Scriptum to the logic of scientific research ") in the sense of affirming that although -effectively- our theories do not reconstruct reality, they do not discover the truth, they can find nodal points of its behaviour; for him probability is physically real, it is a propensity, a tendency that is in things, -as are the Newtonian forces- and that we discover in our experiments. These propensities of the physical world allow for a certain correlation between knowledge and reality; this assertion implies for the first time in Popper's thought the acceptance that truth may be to some extent attainable.
d) Psychological factors in science and scientific relativism development
In recent years, and largely as a reaction to the logical positivism of the Vienna Circle, approaches have emerged that attempt to explain the method and progress of science on the basis of primarily or exclusively psychological factors.
One of the first and main reactions against positivism was led by N.R. Hanson, who attacked one of its weak points: the drastic distinction it makes between observation and theory, claiming that observations are not imbued with any theoretical interpretation, but are solid data against which theories are contrasted. Hanson attacked this point by arguing that, on the contrary, scientific observations are always theoretically interpreted, "theory-laden". Another objection he raised to logical positivism is that, by interpreting scientific reasoning as the testing of previously constructed theories, it denies that there is any reasoning that can lead to the development of a theory. Hanson focuses his attention on finding and argues that, just as there is a logic of refutation, there is also a "logic of finding".
There are indeed many elements that play a crucial role in the elaboration of a theory. As sample History of Sciences, the great scientific advances have not come simply from an accumulation of data, or from the appearance of new instruments, but, rather, from an intuition that is based on one's own Philosophy, on analogies, etc. Moreover, sometimes the author of a theory himself is not able to explain how he came to formulate it.
In the 1960s, Hanson's ideas were developed by Thomas Kuhn of Princeton University. Kuhn starts from the idea that with the logic of the Vienna circle, the fundamental role that intuition, imagination and, above all, the capacity for receptivity to new ideas play in the "structure of scientific revolutions" (as he calls one of his books) has been forgotten. Science would not be a rational way of approaching reality knowledge , but the result of compromises between scientists who accept and share theories, methods, paradigms. What really counts are not rational factors, but the historical and psychological context of the scientist. For this reason, he divides the development of Science into two periods: periods of "normal" or peaceful "Science" and violent "intellectual revolutions".
During periods of normal science, scientists group together, sharing the same paradigms, the same exploration plans that allow them to solve the puzzle of data and ignoring, during these periods, those data that are far away, that do not fit. But the tranquillity of these periods does not last; the data that contradict the explanations cannot be ignored indefinitely, nor can new developments be avoided. In the midst of strong polemics, new paradigms are then proposed, almost always "by very young or very new men in the field"; the struggle to maintain the old paradigms begins, and this struggle - according to Kuhn - is essential to the process of Science; he goes so far as to affirm that "the skill between paradigms is not a battle that can be resolved with proofs"; submission to a new paradigm "is a conversion experience that cannot be forced": logic and experiments are not enough, but the support for this conversion is to be found in individual factors, aesthetics or the confidence it presents as the capacity to resolve the anomalies that have appeared, etc. The criterion, the basis, for changing one hypothesis or theory for another, would not therefore be in the evidence, but in a "decision of a group of scientists", and, therefore, the new paradigms do not always have to mean a closer approach to reality.
Some have gone even further than Kuhn in this line. Thus, for example, Feyerabend, a Viennese philosopher who has worked at the universities of California and Berkeley, claims that it is not true that there are not even such periods of "normal science"; scientists, he says, make their decisions purely for political reasons, propaganda, power, age, etc. There are no rational methods in science, he says, and crises are resolved by systems of rhetoric, deception, subterfuge or propaganda.
If this were the case, it would not be possible to understand the knowledge and scientific progress; the supposed scientific knowledge would be reduced to the prejudices of a group. And thus there is no way to account for the rationality and progress of science. From these perspectives the concept of progress in Science is absolutely relative; the adoption of a new theory would simply mean that it is psychologically more satisfactory, but not that it is truer, more apt to provide an explanation of reality.
As sample the History of Science, prejudices, personal interests, etc., play a role, one might say, in how quickly a theory is accepted by academic community or what obstacles are placed in the way of that acceptance; it is part of the History of Science, but it is not an intrinsic part of the scientific method.
e) Scientific truth
The decisive question is therefore the relationship, the adequacy between knowledge and reality. Only if it can be affirmed that with the scientific method man can know reality - albeit in a limited and progressive way - does science make sense, and it is not reduced to an endless search that only leads to conjecture, nor to scientific knowledge being mere prejudices that are evaluated politically.
As we have already mentioned, sufficient certainty is not always achieved for large theoretical constructs - in which aspects that are not directly observable are studied - and therefore certainty is obviously not achieved for such knowledge. However, there are principles or elements of a theory that are certain truths - think of the principle of conservation of energy, the elementary composition of compounds, the existence of metabolic pathways, etc. -, often incorporated into new theories when these replace other, more limited theories. It is true that Science is a constructed knowledge and models are schematic and simplified representations of reality, but this does not mean that Science does not seek to know reality and seeks exclusively to explain or interpret it, to see whether or not it behaves in accordance with its models agreement .
(1) POLO, L. Oral communication.
(2) ARENDT, H. "La condición humana". Seix Barral. Barcelona, 1974. p.379.
(3) ARENDT, H. "La condición humana". Seix Barral. Barcelona, 1974. pp. 340 and 341.
(4) AGAZZI, E., ARTIGAS, M. and RADNITZKY, G. "La fiabilidad de las ciencias". research y Ciencia, 66, 1986.
(5) MARTINEZ DORAL, J.M. Oral communication.