La naturaleza de la verdad parcial
The nature of partial truth
Author: Mariano Artigas
Edited in: R. Martinez (publisher), La verità scientifica, Armando Editore, Rome 1995, pp. 101-111.
The problem of scientific truth lies at the heart of our culture. The enormous progress of the sciences and the reliability of the knowledge they provide has led to serious perplexities. For some, experimental science would be the only valid access to reality or, at least, the paradigm to be imitated by any claim of knowledge rigorous. For others, experimental science would be a second-rate knowledge limited to discovering rather superficial aspects of reality.
Behind these perplexities lies a problem which arose on the occasion of the systematic birth of modern science in the 17th century and which has not yet received a generally accepted solution. Experimental science does indeed combine mathematics and experimentation in a very effective way, but it is difficult to delimit, by purely logical arguments, what the scope of this method is. In fact, although contemporary epistemology has paid a great deal of attention to this problem, there are very different answers and, consequently, perplexities remain about the relationship between scientific knowledge and philosophical reflection.
A classic answer is to affirm that science studies the "how" and philosophy the "why". This establishes a division of functions that would ensure a peaceful and respectful coexistence between two forms of knowledge that, since they deal with different objects, could not be opposed to each other.
However, the simplicity of this answer is deceptive. Thanks to experimental science, we know of the existence of a veritable multitude of entities, properties and processes that are only accessible through the scientific method and which constitute a large part of what we know today about nature and about ourselves: just think, for example, of the genetic mechanisms at the basis of life, the composition and structuring of subject from the microphysical to the astrophysical level, or the functions that the brain plays in the sensitive knowledge , in language and in thought.
It should be added that this knowledge is achieved through complex reasoning that goes far beyond empirical data and involves the finding of the causes of phenomena. Through experimental science we reach a knowledge of reality that far surpasses the positivist ideal, according to which science would limit itself to establishing laws that would be nothing more than constant relations between observable phenomena. Positivism does not account for the actual achievements of science. And it would make no sense to adopt a positivist interpretation of science in order to clear the way for metaphysics. It is true that the method of experimental science does not allow philosophical problems to be studied thematically; nevertheless, it provides many insights without which philosophical reflection runs the risk of operating in a vacuum or on a deficient basis.
Scientific truth is therefore not partial in the sense that it is limited to superficial aspects of reality. Whoever affirms the contrary, thinking that this leaves the way open for the metaphysical and theological speech , is in reality undermining the capacity of human reason and, if he is consistent, he will encounter difficulties when he tries to substantiate the rationality of metaphysics and theology. Distrust of reason, also when it comes to scientific reason, easily leads to fideistic subject positions.
On the other hand, the most influential interpretations of contemporary epistemology are not usually much more fortunate when it comes to specifying the scope of scientific knowledge . The difficulties that scientific realism has to deal with are certainly not negligible. In experimental science, hypotheses are constructed that go far beyond the available data, and the possibilities of verification encounter serious limits from a purely logical point of view. In these circumstances it is understandable that even many who claim to be realists (as is the case with Karl Popper and the Popperians), at the same time affirm that the scientific knowledge is always provisional and fallible. Partial truth would mean, in this view, that knowledge is always conjectural, that we can never achieve certainty, and that progress is achieved only through the elimination of errors and the consequent formulation of new theories that are destined to remain perpetually in the realm of the conjectural. But this interpretation does not reflect the actual achievements of the sciences either. That scientific truth is partial does not mean that it is always conjectural and provisional, since we do, in fact, achieve much genuine knowledge about nature *(1).
The difficulties increase even more when, along the lines of Thomas Kuhn, the emphasis is placed on the psycho-sociological factors of scientific activity in such a way that there does not even seem to be room left for the concept of truth. This approach easily leads to positions of subject relativism, according to which our statements only make sense within paradigms or conceptual systems whose truth cannot be rationally substantiated. The philosopher and theologian might feel comfortable with this interpretation of science, but they should be aware that, here too, the undervaluing of scientific rationality leads, if developed in a coherent way, to the demolition of human rationality in general, which cannot exactly be seen as a benefit for philosophy and theology.
Instrumentalism, which also enjoys a certain audience in current epistemology, takes the above-mentioned drawbacks to the extreme, as it reduces experimental science to a repertoire of models whose value would consist only or mainly in providing the basis for effective technological activity.
Scientific realism claims that experimental science provides true knowledge about reality. My personal perspective is closely related to Evandro Agazzi's "objectualist realism" *(2), and I have expounded it at length elsewhere *(3). Here I will confine myself to commenting on some aspects that are especially related to the partial character of truth. I argue that in experimental science a truth can be achieved which is contextual and therefore partial, but which is at the same time an authentic truth in the sense of correspondence of statements with reality.
In any scientific discipline particular perspectives are adopted to construct the scientific object under study. Basic concepts and operational criteria are needed to theoretically define the systems and their states, and to relate the theoretical constructs to experimental data. The foundational work of any discipline is often difficult, but once it is done, a theoretical and experimental context is available within which intersubjective demonstrations can be made.
To establish such a context, one must accept theoretical and experimental stipulations that are not imposed by the nature of things themselves. However, these stipulations are not arbitrary and do not prevent intersubjectivity, but make it possible: once accepted, it is possible to delimit the validity of theoretical demonstrations and experimental control.
Assuming that valid demonstrations have been achieved within a given scientific context, the contextual truth of the corresponding constructs can be asserted. But is it possible to assert their truth in the strongest sense of correspondence with reality?
A scientific statement will be true if its content corresponds to real situations, taking into account the meaning and reference of the terms of which it is composed. It is not necessary that there be an intuitive correspondence between that statement and reality; it is sufficient that, if we interpret the meaning and reference of the scientific terms of agreement with the established definitions and relate those terms according to the modalities established by the statement, we obtain results that correspond to real situations, as given through observation and experimentation.
Therefore, if we have a well-established objectification, which must include the definition of basic predicates and operational criteria, we can say that contextual demonstrability implies referential demonstrability, since contextual demonstration automatically provides the meaning and reference of what is demonstrated.
In any case, we will always encounter logical difficulties that would seem to prevent even contextual demonstrability and empirical verification of its consequences. Gödel's theorem puts us on our guard against the pretension of formulating complete theoretical systems, and elementary logic sample that the verification of the consequences is not enough to ensure the truth of the premises. Herein lies the strength of conjecturalism, which rightly insists that the hypothetico-deductive method does not, by itself, make it possible to obtain definitively certain conclusions. However, what is impossible by means of resource to pure formal logic becomes possible if we use complementary criteria based on explanatory and predictive power, on the convergence of independent evidence and on the mutual support of different theories. It is understandable and desirable that the scientist is always ready to incorporate eventual corrections or new formulations, but this does not prevent science from achieving knowledge that can be qualified as true. In fact, the consistent fallibilist is forced to regard much knowledge as conjecture, the truth of which he can hardly doubt.
The meaning of partial truth is a consequence of what has just been said. Indeed, if the truth of statements and theoretical systems must be evaluated with reference to the context of the objectivation and stipulations adopted, it is clear that it will always be a truth with respect to particular contexts, that its value will be approximate because it will depend on the precision that can be achieved in each objectivation, and that it will be possible to obtain new truths by progress in objectivations and stipulations. Because scientific truth is contextual, it is also partial.
But this has little to do with conjecturalism. We can and do gain well-established knowledge about reality. For example, the context of classical mechanics is set by the definitions of the concepts of mass, length and time, and by the criteria for interpreting operations performed with balances, rulers and chronometers. Certainly, this point of view does not exhaust reality. But it is also true that the truth of the statements of classical mechanics must be judged in relation to this context and that, in many cases, it can be rigorously established. Scientific statements are not absolute truths, independent of any conceptual and experimental context; however, if they are well proven, they are true in relation to their corresponding context.
Classical mechanics is a paradigmatic example. It is said that, although it has been the best demonstrated and applied theory for several centuries, it has been shown to be false, from which it would follow, according to conjecturalism, that we can never assert truth as definitive. However, classical mechanics still retains its validity, and it is even possible to extend its scope of applicability. We know that it is not applicable to contexts involving very large velocities or very small masses; but this does not mean that it is false: it only means that the context in which it retains its validity has been better delimited.
Thus, the truth of well-attested statements is simultaneously authentic and partial. These statements refer to reality, but view it from the point of view implied by the respective objectification, thus leaving room for further clarification.
A statement will be true or false with respect to the context in which its constituent terms are defined. For example, if it is stated that the typical diameter of an atom is of the order of one angstrom (ten billionths of a metre), or that the brightness of Sirius has a magnitude of -1.58, such statements only make sense in contexts where there are adequate concepts of atom and stellar brightness, and procedures for measuring the quantities being discussed. The truth of a scientific statement is not absolute, that is, independent of any conceptual and experimental framework ; it is relative to such frameworks or contexts. But this has nothing to do with a subjectivist relativism, since contexts are formulated in a way goal and so are demonstrations.
A concrete objectification, however accurate it may be, does not exhaust all that can be said about the realm of reality under study. In this sense, scientific knowledge is always partial. Therefore, when we speak of partial truth, it is not necessary to think of a defective knowledge . All scientific statements, even the most precise ones, refer to a concrete objectification and to certain experimental means, and in this sense the truth that can be attributed to them is always partial.
We can attain authentic knowledge that is at the same time partial, approximate and perfectible. They are partial, because they only refer to those aspects of reality that are accessible to the corresponding objectification. They are approximate, because the theoretical constructs correspond to reality within the margin imposed by the available theoretical and experimental possibilities. And therefore they are perfectible, because we can achieve deeper and more exact objectivations.
If any objectification implies a partial perspective, it can now be added that experimental science, as a whole, adopts a limited perspective. Indeed, for a statement or a theory to be scientifically acceptable, it must meet a minimum requirement: that it can be put in relation to experimental control. This requirement accounts for the reliability of science and, at the same time, for its limits, since there may be realities (such as those belonging to the realm of the spiritual) which, by their very nature, cannot be subjected in any way to experimental control. This does not mean that they do not exist or that they cannot be known; it only means that they cannot be subject to the proper perspective of experimental science.
It is easy to see that, in this sense, scientific truth is always partial, since it does not exhaust all that can be known about reality. Its limits are related to spiritual realities; but they also refer to the ontological and metaphysical dimensions of reality, which also occur in the material realm.
Indeed, experimental science does not study these dimensions thematically, but assumes them. It is based on ontological and gnoseological assumptions. The former include the existence of a real nature that is independent of our knowledge, of a natural order, of causality, of legality. The latter refer to the human capacity to know the natural order, and involve the capacity for argumentation, the sense of evidence, the capacity for self-reflection and the possibility of detecting truth. These assumptions are authentic conditions of possibility for the sciences, since without them scientific activity would be impossible and would not even make sense.
Moreover, science retro-acts on the aforementioned assumptions: it retro-justifies them, because scientific progress assumes them and that progress is real; it expands them, since it provides new particular knowledge about them; and it eventually clarifies them, showing the inadequacy of some previous conceptions that are incompatible with further progress.
All this sample the existence of real dimensions that are not topic proper to experimental science, but are nevertheless part of it by way of assumptions and implications. Nature can be said to possess ontological dimensions (e.g. substantiality, causality, finality), and metaphysical dimensions (e.g. the act of being), which are assumed by the sciences without being their direct object. Experimental science has to do with these dimensions, because reality is unitary, and in some way it reaches them, insofar as they are related to the physical dimensions (understanding "physical" here as "material"): although it does not study them thematically, making them its object, it nevertheless supposes their existence, contributes to their better knowledge and provides elements for a further properly philosophical reflection on them.
I will now turn to the evolutionary worldview because, in addition to its interest in itself, it provides important examples for the topic .
Both cosmic and biological evolution refer to historical processes, the actual development of which cannot be directly subjected to experimental control. However, most scientists admit that our world originated in the big bang some 15 billion years ago; they agree agreement on the general outlines of the physico-chemical processes that would have led to the formation of nuclei, atoms, stars, galaxies, and our planet; and they also admit the physico-chemical and biological processes that would have led to the origin and progressive development of living things on Earth from some 3.8 billion years ago to the present day. Many difficulties remain about the particular explanations, and it seems unlikely that definitive explanations will be found. However, there is a fairly widespread agreement about the general picture.
If we think of the evolutionary worldview, it does not seem possible to say that science is limited only to the "how", or to superficial aspects of reality. Indeed, this worldview involves a far-reaching conceptual change compared to the ancient worldview, affecting important areas of human existence. It undoubtedly contains many hypothetical aspects and, in this sense, can be studied simply as a more or less plausible hypothesis; however, it is difficult to disregard its possible implications.
The evolutionary worldview is sometimes presented as if it were a complete explanation of the origin of the universe, of life and of man, so that nothing should be added to the data and hypotheses provided by the sciences. In this case, we are faced with a reductionism that methodically disregards the ontological and metaphysical dimensions and sometimes openly denies their existence. This pan-evolutionism leaves no room whatsoever for divine intervention, human spirituality and finality, since it seeks to explain everything by recourse to blind forces of a physical nature. It does not even stop at the problem of the origin of the universe; strange as it may seem, it sometimes appeals to an alleged self-creation of the universe that could be explained by physical laws *(4). Moreover, although it is now generally accepted that evolutionism and Christianity are compatible, there are those who claim that evolution may be incompatible with Christianity *(5).
To clarify these confusions it can be noted that the evolutionary worldview contains many hypothetical aspects and that experimental science, by its own method, cannot deny the existence of spiritual realities. Both observations are true and important. However, it will be difficult to obtain a more complete perspective, not only to clarify confusions but also to move forward in a positive way, if we do not go deeper into the real scope of the scientific method which, although it encounters the barrier of what cannot be submitted to experimental control, refers to physical dimensions that are interpenetrated with the ontological and metaphysical dimensions and, therefore, contributes to a better knowledge of the latter.
Indeed, the evolutionary worldview is a part of a broader worldview that provides new and interesting philosophical perspectives. It can be said that for the first time in history we have a scientific worldview which, without being exhaustive, can be broadly described as complete, because it extends to all levels of nature and relates them to each other. Major advances in microphysics have made it possible to understand the composition and functioning of the chemical, geological, astrophysical and biological levels, and to relate these levels to each other, showing their mutual harmony and dependence. This knowledge is, of course, partial in the ways already mentioned, but much of it is well established and can therefore be described as true.
It may be added that the best antidote to pseudo-scientific scientism consists in a rigorous reflection on this worldview, as well as on its assumptions and implications, which implies not emphasising the limitation of the scientific knowledge (i.e. the partial character of scientific truth), but its positive aspect (i.e. the truth of the knowledge achieved). I have developed my ideas on this subject at length elsewhere *(6); I will now refer to some aspects that I consider particularly relevant.
The current scientific worldview emphasises the dynamism of the natural, in its structuring centred on patterns, and in the close relationship between both aspects. Nature appears to us as the unfolding of a dynamism that produces Structures which, in turn, are source of new dynamisms, and this happens not only at the biological level, but also at the physico-chemical level. Morphogenetic theories build bridges between these levels, and it is understood that the fabulous dynamic complexity of any organism would be impossible if at the physical-chemical level, as postulated by mechanicism, the subject were in itself passive and inert.
To summarise the current worldview, one often speaks of the self-organisation of the subject *(7). This expression reflects the dynamism of the natural, its structural character, and the interpenetration of dynamism and structuring. Undoubtedly, it can constitute a new misunderstanding source if it is interpreted from a naturalistic perspective, as if nature did not need any further foundation. But if this misunderstanding is avoided, it provides a solid basis for the reformulation of the central problems of the philosophy of nature.
Consider, for example, the problem of purpose. Nature, including our own organism, appears to us as the result of a veritable multitude of enormously sophisticated and specific processes, which imply a directionality. The sciences do not reflect thematically on finality, but they provide many insights that can be seen as particular manifestations of a directionality that appears to us in the form of tendencies and cooperativity. The existence of the higher levels of complexity depends on the specific properties found at each of the lower levels and, ultimately, on the basic characteristics of the physical level; and these are closely related to the conditions of the primitive universe. It is understandable that this world view provides a broad basis for the reflections usually included under the heading of the anthropic principle *(8).
There is no unanimity among scientists on the implications of this principle, which, moreover, has received different formulations. However, it is clear that the current worldview considerably broadens the empirical basis of the problem of finality and, to a large extent, even seems to suggest its approach. This confirms that, although the partial character of scientific truth makes it possible to avoid unjustifiable extrapolations, we will only succeed in adequately representing the implications of science if we take into account that this partial truth is a real knowledge that often opens up important horizons for philosophical reflection.
Similar reflections arise with regard to other problems in the fields of the philosophy of nature, anthropology and natural theology. The concept of subject can be freed from the negative connotations which, in the purely philosophical field, the mechanistic image of a passive and inert subject entailed. The concept of substance, as well as being particularly appropriate when applied to living beings, can be applied to the unitary systems of the microphysical world and to other systems whose mode of being has holistic characteristics. Potentiality manifests itself through capacities, dispositions and tendencies that are closely related to teleological behaviours. In these and similar cases, today's worldview invites consideration of the interpenetration between physical, ontological and metaphysical dimensions, and their distinction, hierarchy and grounding.
By referring briefly to these examples, I intend to underline, as I have already said, the interest of focusing on the authentic character of well-tested scientific knowledge, without forgetting its partial character, but bearing in mind that partial is here an adjective applied to authentic knowledge about reality.
This is a particularly interesting time for metaphysical and theological thought. instructions The current scientific worldview favours the rethinking of perennial problems on new instructions , and this reflection can lead to a harmonious integration between Christian thought and a science whose maturity makes it possible to overcome old ambiguities and to lay the groundwork for a highly desirable mutual understanding which, while respecting the legitimate difference and autonomy of the respective fields of knowledge, is at the same time capable of illuminating in a coherent way the different aspects of the unitary reality in which we live.
- On fallibilism, see: M. Artigas, Karl Popper: Búsqueda sin término, Emesa, Madrid 1979; "knowledge humano, fiabilidad y fallibilismo", yearbook Filosófico, 25 (1992), pp. 277-294.
- Vid. E. Agazzi, Temi e problemi di filosofia della fisica, Abete, Roma 19742; "Eine Deutung der wissenschaftlichen Objektivität", Allgemeine Zeitschrift für Philosophie, 3 (1978), pp. 20-47; "Verité partielle ou approximation de la verité?", in: AA. VV., La nature de la verité scientifique, Ciaco, Louvain-la-Neuve 1986, pp. 103-114; M. Artigas, "Objectivity and Reliability in Science", Epistemologia, 11 (1988), pp. 101-116.
- Vid. M. Artigas, Filosofía de la ciencia experimental, Eunsa, Pamplona 19922, chap. VI; "Three Levels of Interaction between Science and Philosophy", in: C. Dilworth (ed.), Intelligibility in Science, Rodopi, Amsterdam 1992, pp. 123-144.
- This is what the biologist R. Dawkins does, for example, in The Blind Watchmaker, referring to the ideas on the alleged self-creation of the universe formulated by the physicist P. Atkins. This is an issue that is currently being addressed in both scientific and popular science writings. On this topic, see: M. Artigas, "Física y creación: el origen del universo", Scripta Theologica, 19 (1987), pp. 347-373; "Explicación física y autocreación del universo", in: AA. VV, El hombre: inmanencia y transcendencia, University of Navarre, Pamplona 1991, volume I, pp. 109-129; D. Andresciani, "Lo studio dell'origine dell'universo nel contesto della cosmologia quantistica", Excerpta e dissertationibus in philosophia, School Eclesiástica de Filosofía, University of Navarre, vol. III, Pamplona 1993, pp. 9-88; W. E. Carroll, "Big Bang Cosmology, Quantum Tunneling from Nothing, and Creation", Laval Théologique et Philosophique, 44 (1988), pp. 59-75; W. L. Craig, "Theism and Big Bang Cosmology", Australasian Journal of Philosophy, 69 (1991), pp. 492-503.
- See M. Ruse, The Darwinian Paradigm. Essays on its history, philosophy, and religious implications, chap. 10: "Evolutionary theory and christian ethics. Are they in harmony?", Routledge, London 1989, pp. 251-272.
- Especially in: M. Artigas, La inteligibilidad de la naturaleza, Eunsa, Pamplona 1992.
- An example of these ideas that have come to constitute a new scientific and cultural paradigm can be found in the studies, with very different ideological inspirations, contained in: P. Dumouchel - J. P. Dupuy (eds), L'auto-organisation. De la physique au politique, Editions du Seuil, Paris 1983; W. Krohn - G. Küppers (eds), Selbstorganisation. Aspekte einer wissenschaftlichen Revolution, Vieweg, Braunschweig 1990.
- On this subject see: J. D. Barrow - J. Tipler, The Anthropic Cosmological Principle, Clarendon Press, Oxford 1986, which is already a classic on these subjects, even if one does not find Exempt philosophical meanderings.