Publicado en G. Debrock, ed. Process Pragmatism:
Essays on a Quiet Philosophical Revolution,
Rodopi, Amsterdam, 2003, 39-49
"The Law of Love and the Law of Reason are quite at one."
C. S. Peirce, Science, 20 April 19001.
In a world of ever growing specialization, the idea of a unity of science is commonly discarded as an impossible ideal. Yet, at the same time, co-operative work involving cross-disciplinary points of view is usually encouraged, though seldom practiced, both as a remedy against the conceptual poverty of the scientific reductionism inherited from logical positivism of the Vienna Circle, and as a way of efficiently tackling the most stubborn and still unresolved problems which our society is facing today. The generation of knowledge is commonly perceived as a strange mixture of hard cross-disciplinary research, personal imagination and a lot of luck; a mixture which calls to mind the saying: ninety per cent perspiration and ten per cent inspiration; or perhaps better, ninety per cent team perspiration and ten per cent individual inspiration.
As Debrock highlighted, Charles S. Peirce's thought helps us to re-assume philosophical responsibility which has been largely abdicated by much of 20th century philosophy and offers suggestions for tackling some of these stubborn contemporary problems (Debrock 1992, 1). The founder of pragmatism not only identified one century ago this paradoxical situation about scientific development, but he also mapped out some paths that we could follow in order to get a clearer view of the problem and to genuinely improve the communication between the various sciences. Along this line, the aim of my paper is to understand from a Peircean point of view the nature of scientific growth and the essential need for cooperation and cross-disciplinarity to develop new knowledge. With that purpose in mind, my paper will be divided in three sections: 1) a short presentation of Peirce, stressing his personal authority on this issue; 2) a selection of texts from the mature Peirce about science and the nature of scientific growth; and, finally, 3) an attempt to understand how -according to Peirce- communication and love can be effective to achieve real cross-disciplinarity.
As you very well know, the figure of Charles S. Peirce has an ever increasing relevance in very different areas of knowledge (Fisch 1980), and his influence is still growing (von Wright 1993: 41): in astronomy, metrology, geodesy, mathematics, logic, philosophy, theory and history of science, semiotics, linguistics, econometrics, and psychology. In all these fields Peirce has been considered a pioneer, a forerunner or even a 'father' or 'founder' (of semiotics, of pragmatism). It is not uncommon to find superlative evaluations such as Russell's "beyond doubt ... he was one of the most original minds of the later nineteenth century, and certainly the greatest American thinker ever" (Russell 1959: 276). It would be possible to make similar quotations from Umberto Eco (Eco 1989: x-xi), Karl Popper (Popper 1972: 212), Hilary Putnam (Putnam 1990: 252), and many others.
All of this is a commonplace in the present revival of the scholarship on Peirce, but the point I want to stress, first of all, is that Charles S. Peirce should not to be considered mainly a philosopher or a logician, but a real practitioner of science. Peirce not only was trained as a chemist at Harvard, but he worked regularly and strenuously for thirty years (1861-91) for the U. S. Coast Survey as a metrologist and as an observer in astronomy and geodesy. His reports to the Coast Survey are an outstanding testimony of his personal experience in the real hard work of measuring and obtaining empirical evidence. A glance at his official reports to the Coast Survey or at his Photometric Researches produced in the years 1872-75 provides a vivid impression —at least to the lay person— of solid scientific work (W 3: 382-493, 1878) 3. As Max Fisch wrote, "Peirce was not merely a philosopher or a logician who had read up on science. He was a full-fledged professional scientist, who carried into all his work the concerns of the philosopher and logician" (W 3: xxviii-xxix).
And perhaps I could entice you into a smile at this early hour of the morning, by recalling a delightful example of Peirce's scientific style which may be found in Essential Peirce 1 (W 3: 236, 1877; EP 1: 107-8):
... it is commonly said (I mean by physicists) that there is no meaning in the comparison of the intensity of a red and green light. Here I have 74 pieces of different coloured ribbons each one numbered upon which I have made frequent photometric experiments extending over a period of 12 months. Now I say that a red and green can be compared in intensity with a considerable degree of accuracy. On another occasion, when the figures are relevant, I will give them. They are not so now, because you can all see that that red is darker than that blue & that that blue is darker than that red. There is an uncertainty in the judgment, a probable error. But that probable error is only another fact, another numerical determinate relation between the two sensations.
Though the folder of the Houghton Library, which contains this manuscript gives no further information on the matter (MS 1104), there is another folder (MS 1023) which cointains a dark grey envelope, which on the outside is marked in black ink with the words: "74 Scraps of Ribbon-Numbered in order of apparent brightness of light by CSP on a dark day". I sent an e-mail to Melanie Wisner in the Houghton Library asking her to check for these ribbons, and she answered me that there are just eleven scraps of ribbon in the envelope: the numbers are written in ink directly on the scraps in a corner, but some of the numbers are now illegible through fading.
The second preliminary point I want to make has some relation to Peirce's visit to Spain in 1870. The circumstances of that journey bear witness to the wide scope of Peirce's interests. Let me recall these for you. In 1861, when finishing his studies in the Lawrence Scientific School at Harvard, Peirce started to work as an assistant to his father, Benjamin, in the Coast Survey, which was the American government's principal scientific body at that time. In 1869, he was a member of one of the teams in Kentucky studying the total eclipse of the sun on August 7th (W 2: 290-3). The observation through telescopes of the solar corona and its protuberances, and the detection of helium by means of the spectroscope, led the American astronomers to formulate new theories regarding the composition of the sun, that were received with a certain skepticism by European astronomers (W 2: xxxii).
As no other such favorable occasion was going to arise in the nineteenth century, Benjamin Peirce, the third Superintendent of the Coast Survey, obtained an appropriation from the Congress to organize an expedition to observe the next solar eclipse, which was to take place at midday on December 22, 1870 over the Mediterranean Sea. In order to ensure the success of the project, he sent his son Charles to organize the preparations in Europe six months beforehand. Charles passed through London, Rotterdam, Berlin, Prague, Vienna, Pest, arriving finally in Constantinople. From Constantinople he traced back along the entire path of totality of the eclipse from East to West in search of locations suitable to observe the phenomenon. In Italy Peirce selected some sites in Sicily, and in Spain one site in Marbella and another in Jerez.
When the time came, Charles S. Peirce joined one group of American scientists, which included his wife Zina and his father Benjamin, who observed the eclipse in the vicinity of Catania (Sicily), even though his spectroscope was sent by mistake to Jerez, where the second group from the Coast Survey was stationed. Although the day turned out to be cloudy, with some rain, the observations made by both expeditions were successful, and confirmed the conclusions drawn by the Americans on the basis of the previous eclipse. As Joseph Brent wrote, "this expedition was Charles's first experience of large-scale international scientific cooperation, and it illustrated for him the importance of the community of science in reevaluating and validating its hypotheses" (Brent 1993: 80; W 2: xxxiv) 4. As you know, the most valuable scientific work of Charles Peirce was probably in the area of geodesy, the science of measuring the Earth, which demands cooperation between teams in different countries and continents. In his own words: "Geodesy is the one science the successful prosecution of which absolutely depends upon international solidarity" (W 3: xxvi, 1879).
Peirce's personal participation in the scientific community of his time buttresses whatever he has to say about science from a philosophical point of view. As you well know, the interpretation of Peirce's thought and its evolution from his early writings in 1865 until his death for many years provoked wide disagreement amongst Peirce scholars. This was due in part to the fragmentary presentation of his work in the Collected Papers, and in part to his going against the grain. In recent years a deeper understanding of the architectonic nature of his thought and of his whole evolution has been gaining general acceptance (Hausman 1993: xiv-xv; EP 1: xxix). In the last decade all Peircean scholars have clearly acknowledged the basic coherence and undeniable systematization of his thought (Santaella-Braga 1993: 401; Hausman 1993; Parker 1998).
Following Hookway to some extent (1985: 1-3), I think that the most accurate understanding of Peirce is to see him as a traditional and systematic philosopher, but one dealing with the modern problems of science, truth and knowledge from a very valuable personal experience as a logician and as an experimental researcher in the bosom of an international community of scientists and thinkers. In addition to his personal experience of scientific practice, his sound knowledge of the history of science and of the history of philosophy helped him to establish a general cartography of scientific methodology.
Having done research in astronomy, mathematics, logic and philosophy and in the history of all these sciences, in spite of their very different professional labels, Peirce tried throughout all his life to disclose the links between the various kinds of scientific inquiry. Unfortunately methodology, the "branch of logic which teaches the general principles which ought to guide an inquiry" (Baldwin 1901: 75), has been the cinderella of logic in our century. To make things worse, his study of scientific methodology has often been pigeon-holed under the general title of "Classification of the Sciences", which is usually considered the despicable domain of librarians or academic administrators. But a closer study of Peirce's conception of science as a collective and co-operative activity of all those whose lives are animated by the desire to find out the truth (MS 615, p. 14, 1908), and by "an impulse to penetrate into the reason of things" (CP 1.44, c.1896), may enable us -as Debrock (1992) stressed- to identify him as a true philosopher for the 21st century also in this realm of cross-disciplinarity.
As I said before, from his first experiences as a young scientist on, Peirce believed that the community of inquirers was essential for scientific rationality. For him, the flourishing of sciences can only take place in the context of research communities: the pursuit of truth is a corporate task and not an individual search for foundations. As Peirce wrote in The Ethics of Terminology, "the progress of science cannot go far except by collaboration; or, to speak more accurately, no mind can take one step without the aid of other minds." (CP 2.220, 1903). This communitarian framework for understanding scientific activity, as Bernstein (1983, 71-72) remarked, "not only challenges the characteristic Cartesian appeal to foundations, but adumbrates an alternative understanding of scientific knowledge without such foundations".
And, what is a science for Peirce? I want to provide two beautiful texts of the mature Peirce defining what a science is. The first one is from a manuscript of 1902 on the classification of the sciences (MS 1343, pp. 6-7, 1902):
The second text comes from the manuscript of the Adirondack Summer School Lectures and deserves to be quoted extensively (a fragment of it has been used as a motto for my Spanish Group of Peirce Studies!):Science is to mean for us a mode of life whose single animating purpose is to find out the real truth, which pursues this purpose by a well-considered method, founded on thorough acquaintance with such scientific results already ascertained by others as may be available, and which seeks cooperation in the hope that the truth may be found, if not by any of the actual inquirers, yet ultimately by those who come after them and who shall make use of their results (CP 7.55, 1902).
But what I mean by a "science", both for the purpose of this classification and in general, is the life devoted to the pursuit of truth according to the best known methods on the part of a group of men who understand one another's ideas and works as no outsider can. It is not what they have already found out which makes their business a science; it is that they are pursuing a branch of truth according, I will not say, to the best methods, but according to the best methods that are known at the time. I do not call the solitary studies of a single man a science. It is only when a group of men, more or less in intercommunication, are aiding and stimulating one another by their understanding of a particular group of studies as outsiders cannot understand them, that I call their life a science. It is not necessary that they should all be at work upon the same problem, or that all should be fully acquainted with all that it is needful for another of them to know; but their studies must be so closely allied that any one of them could take up the problem of any other after some months of special preparation and that each should understand pretty minutely what it is that each one of the other's work consists in; so that any two of them meeting together shall be thoroughly conversant with each other's ideas and the language he talks and should feel each other to be brethren. In particular, one thing which commonly unites them is their common skill unpossessed by outsiders in the use of certain instruments and their common skill in performing certain kinds of work (MS 1334, pp. 11-14, 1905)5.
Actually, this text serves as a salutary admonition against the present state of competitiveness amongst scientists in the same field or in the same department battling to gain the Nobel prize or a modest postdoc grant!
Peirce carefully studied upwards of a hundred different classifications of the sciences and made many attempts to work out his own general classification of the sciences, as so many branches and sub-branches of a tree, springing out of one another (CTN 3, 217, 1905; L 75, 1902; HP 805, 1904 and 1124, 1899). Although he supported Comte's view of each science as a historical development6, he disliked Comte's metaphor of sciences forming "a sort of ladder descending into the well of truth, each one leading on to another, those which are more concrete and special drawing their principles from those which are more abstract and general" (CP 2.119, c.1902; cf. MS 1334, 1905). Peirce preferred a natural classification, that is, one which embodies "the chief facts of relationships between the sciences so far as they present themselves to scientific and observational study" (MS 1334, 1905). Since a science is the actual living occupation of an actual group of living people, it is a natural object (MS 1334, 1905), and a natural classification must exhibit the living relations between the different branches of research, between the different traditions of researchers:
A particular branch of science, such as Physical Chemistry or Mediterranean Archeology, is no mere word, manufactured by the arbitrary definition of some academic pedant, but is a real object, being the very concrete life of a social group constituted by real facts of interrelation (CP 1.52, c-1896).
Following Peirce, "sciences must be classified according to the peculiar means of observation they employ" (CP 1.101, c.1896), because each community of scientists grows around some specific ways of perceiving, some special methods of research. Each science corresponds then to a special kind of observations which renders peculiar the modes of thought of the students of each special branch (CP 1.100, c1896). The scientists are
Men who spend their lives in finding out similar kinds of truth about similar things understand what one another are about better than outsiders do. They are all familiar with words which others do not know the exact meaning of, they appreciate each other's difficulties and consult one another about them. They love the same sort of things. They consort together and consider one another as brethren. They are said to pursue the same branch of science (HP 804-5, 1904).
I will not go now into the details of Peirce's classification of sciences. It has been nicely studied by, for instance, Beverley Kent (1987) and Kelly Parker (1998). The texts I have selected suffice to show that for the mature Peirce "science is a living historic entity" (CP 1.44, c.1896), "a living and growing body of truth" (CP 6.428, 1893). Nevertheless, I want to add that these texts are strikingly relevant to our contemporary views regarding the nature of science, because they shift the emphasis of the discussion from the view of sciences as objects to be classified towards the lives of real men involved in the scientific research. Indeed, in Peirce's view, the sciences of discovery are to be identified with the lives of their practitioners. Certainly Peirce regarded the point relevant to the common view of science in his own time: "even now there is but a minute fraction of the population anywhere who understand what is that scientific men mean in their perpetual use of the words 'science' and 'scientific'. This is shown by the common definition of science as systematic knowledge" (HP 1123, 1899). To illustrate this point, I need to quote another long text, also from de Adirondack Summer School Lectures:
All human lives separate themselves and segregate themselves into three grand groups whose member understand one another in a general way, but can ['t] for the life of them understand sympathetically the pursuits and aims of the others. The first group consists of the devotees of enjoyment who devote themselves to carving their bread and eating as fine bread as they can and who seek the higher enjoyments of themselves and their fellows. This is the largest and most necessary class. The second group despises such a life and cannot fully understand it. Their notion of life is to accomplish results. They build up great concerns, they go into politics (...) This group makes civilization. The men of the third group who are comparatively few cannot conceive at all a life for enjoyment and look down upon a life of action. Their purpose is to worship God in the development of ideas and of truth. These are the men of sciences (MS 1334, pp. 11-14, 1905).
The text continues with the division of men of science according to their different conceptions of the purpose of science. In this context, Peirce distinguishes the Practical Sciences from the Sciences of Review, and then adds a third group which he calls the heuretics or heurospudists. These are the men who endeavor to discover, and who "look upon discovery as making acquaintance with God and as the very purpose for which the human race was created" (MS 1334, p. 20, 1905).
This may sound a little strange to our positivistic ears, but as Kelly Parker stresses, understanding the continuity of Peirce's thought requires dealing with Peirce's religious concerns, which are increasingly recognized as being perhaps as philosophically important as his scientific concerns (Parker 1998: 231 n. 5). But to come back to my point, Peirce stresses the point that the commonly perceived image of science as something finished and complete, is totally opposite to what science really is at least in its original practical intent. What appears to the outsider as the most solid aspect of science is seen by its practioners as its weakest part. The brilliant hypotheses that impress the layman are seen by the trained people as no more than educated guesses which are natural to them as flying and nest-building is to ordinary birds (CP 6.476,1908).
And what is the nature of scientific growth for Peirce? Scientific growth is not only the accumulation of data, of registrations, measurements or experiences. Though the scientist is invariably a man who has become deeply impressed with the efficacy of minute and thorough observations, he knows that observing is never enough: his "ultimate aim is to educe the truth" (HP 1123, 1898). To learn the truth requires not only collecting data, but abduction, the adoption of a hypothesis to explain the surprising facts, and the deduction of probable consequences which are expected to verify his hypotheses (CP 7.202, 1901)7.
My own historical studies, which have been somewhat minutely critical, have, on the whole, confirmed the views of Whewell, (...) that progress in science depends upon the observation of the right facts by minds furnished with appropriate ideas. Finally, my long investigation of the logical process of scientific reasoning led me many years ago to the conclusion that science is nothing but a development of our natural instincts. So much for my theory of scientific logic (CP 6.604, 1891).
This somehow naturalistic account of science paves the way to understand with more clarity the role of communication as an essential practice of scientific life.
As we have seen, Peirce identified science as a diligent inquiry into truth for truth's sake developed by a community of inquirers skilled in the manipulation of particular instruments, and trained in some ways of perceiving or peculiar modes of thought. Sciences are traditions of research which have developed in both time and space. For Peirce, "science does not advance by revolutions, warfare, and cataclysms, but by cooperation, by each researcher's taking advantage of his predecessors' achievements, and by his joining his own work in one continuous piece to that already done" (CP 2.157, c.1902). Science is a way of life, a craft handed down from masters to apprentices. Scientific method "is itself a scientific result. It did not spring out of the brain of a beginner: it was a historic attainment and a scientific achievement" (CP 6.428, 1893).
For this reason, the key to the advancement of knowledge and to the development of sciences is not revolution, but communication. Communication between the members of a science community is essential for scrutinizing the evidence and the results achieved in research. Because there is no algorithm —no routine or unfailing method— for finding out the truth or knowing sure when you have it, truth and knowledge at least in the hard sciences are located at the level of the scientific community rather than the individual inquirer (Ransdell 1998: 2). We can quote Peirce again, "I do not call the solitary studies of a single man a science. It is only when a group of men, more or less in intercommunication, are aiding and stimulating one another (...) that I call their life a science" (MS 1334, 1905).
More specifically, Peirce clearly asserts that the scientific community far from being an assembly or a parliament, whose members fight each other with fierce arguments, should be more like a family. "A given science with a special name, a special journal, a special society, studying one group of facts, whose students understand one another in a general way and naturally associate together, forms what I call a family" (CP 1.238, c.1902). A scientific community is always -or at least should be according to Peirce- an affective community. In this respect, scientific practice is unfortunately quite different. It is not uncommon to find in our time fields of research in which "disputational activity is for the purposes of annihilation of the opponent rather than regarded as part of a process aiming at mutual accommodation" (Ransdell 1999).
A second point of interest is the encouragement of cross-disciplinarity between sciences: "One of the most salient phenomena of the life of science is that of a student of one subject getting aid from students of other subjects" (HP 805, 1904). It is not only that "... the higher places in science in the coming years are for those who succeed in adapting the methods of one science to the investigation of another. That is what the greatest progress of the passing generation has consisted in" (CP 7.66, 1882), but that new knowledge is generated wherever communication between different branches of science is enhanced.
Peirce provides an impressive amount of historical evidence. His account of the cooperation between the sciences of the earth and the astronomy and the so-called physics of the globe to establish the relative position of the elements of our planet; of the help that comes to linguistics from phonetics and from acoustics; of the historian regulating his chronology to conform the information furnished by the astronomer, and learning the distances and other spatial relations from the geographer, and so on (HP 805-6, 1904). Of course, cross-disciplinarity can adopt several different forms:
By far the most ordinary way in which one science extends a service to another is by furnishing it with a new fact which the aided science treats as if it were a direct observation. (...) the science which receives that fact, when it has performed its generalization of the fact, will return to the science which furnished that fact an explanation of it (HP 809, 1904).
Peirce also stresses the importance of,
... the dynamical relations between the different sciences, by which I mean that one often acts upon another, not by bringing forward any reason or principle, but as it were with a compulsive quality of action. Thus one group may stimulate another by demanding the solution of some problem. In this way, the practical sciences incessantly egg on researches into theory (CP 7.52, n.d.).
In contrast to science which grows upon special experience, philosophy is precisely "that science which limits itself to finding out what it can from ordinary everyday experience, without making any special observations" (HP 825, 1904). While special sciences grow in laboratories or in very sophisticated contexts of research, the laboratory of the philosophers is our ordinary experience, our real lives even in academic environments.
For this reason, we philosophers are in a better position to call for the unity of sciences, but this calling should not be seen as a return to the old scientism of Neurath's failed attempt at an International Encyclopedia of Unified Science. The unity of science is not achieved by the reduction of special sciences to more basic ones. The new name for the unity of the sciences is cross-disciplinarity, not the unity of the science, but the unity of the scientists, the real inquirers of the truth. The key to cross-disciplinarity of knowledge is not revolution, but sharing efforts in a very peculiar mixture of continuity and fallibilism, of affection and reason, the attempt to understand others as well as oneself, putting oneself in the shoes of the others and walking several moons with them.
From a Peircean perspective, the communication between the branches of science is the effect of the efforts of a real community of human beings trying to share their discoveries. It involves the commitment of each scientist to be a kind of philosopher, because the scientist has to bring together into a single field of activity the universe of ordinary experience and the universe of scientific experience. Perhaps it is the special mission of the philosopher for the new century to train the scientists in the Socratic tradition by which to really achieve this.
But, is it possible to establish real affective relations between disciplines? I do not have a clear answer strictly based on texts of Peirce, but he gives me the master key to his conception of science and pragmatism which I have used to give name to my paper:
... experience of life has taught me that the only thing that is really desirable without a reason for being so, is to render ideas and things reasonable. One cannot well demand a reason for reasonableness itself. Logical analysis shows that reasonableness consists in association, assimilation, generalization, the bringing of items together into an organic whole -which are so many ways of regarding what is essentially the same thing. In the emotional sphere this tendency towards union appears as Love; so that the Law of Love and the Law of Reason are quite at one (1900).
And we have a surprising fact in front of our eyes, and it is the joyful reality of this small Department of Philosophy in the bosom of a large Faculty of Science. Thanks to the personal conviction of his chairman regarding these ideals of communication, love and reason, a real cross-disciplinary community has been built, as the success of this International Colloquium provides evidence. In some sense, this fact confirms the Peircean image of the scientific community as a family, with a peculiar mixture of interaction and differences, kept united by agape (Hausman 1974; 1998, 97). Since truth is the goal of scientific inquiry, and love a distinctive feature of truth, we are allowed to conclude with some solemnity, paraphrasing Peirce: "The Law of Reason is the Law of Love".
1. "Review of Clark University, 1889-1899. Decennial Celebration", Science 11 (1900), p. 620; reprinted in P. P. Wiener, ed., Charles S. Peirce: Selected Writings. (Values in a Universe of Chance), Dover, New York, 1966, p. 332.
2. This paper is related with my oral presentation to the 10th International Congress of Logic, Methodology and Philosophy of Science held in August 22, 1995, in Florence (Italy) with the title "The Branching of Science according to Peirce", and my contribution to the Section of American Philosophy in the Twentieth World Congress of Philosophy, held in August 10-16, 1998, in Boston, with the title "A Plea for a Peircean Turn of Analytic Philosophy". Both papers benefited a lot with suggestions and comments from Guy Debrock, even the title of the last one was his. I am grateful also to the help and comments of Sara Barrena, Ruth Breeze and Melanie Wisner, and to the suggestions of Carl Hausman and Menno Hulswit when I presented the paper presented in the Nijmegen Colloquium.
3. Pierre E. Bour has studied the Photometric Researches and concluded that "les différents points de vue théoriques adoptés par Peirce (philosophique, psychologique, physique) constituent autant de points de vue, certes autonomes, mais interconnectés dans un approche globale pluri- et transdisciplinaire d'un objet". P. E. Bour, "Les Recherches Photométriques de C. S. Peirce: une tentative d'application épistémologique des conceptions peirciennes en philosophie de la perception", Astronomie et Sciences Humaines 11 (1995), 11.
4. In my paper, "C. S. Peirce and the Hispanic Philosophy of the Twentieth Century", Transactions of the Charles S. Peirce Society 24/1 (1998), 31-49 may be read the available details of Peirce's visit to Spain.
5. This text was first published by Ken Ketner under the title "The Nature of Science" in J. J. Stuhr (ed.), Classical American Philosophy. Essential Readings and Interpretative Essays, Oxford University Press, Oxford, 1987, 49-50. It was translated into Spanish by Sara F. Barrena and included in our collection Claves del pensamiento de C. S. Peirce para el siglo XXI, special issue of the journal Anuario Filosófico XXIX/3 (1996), 1435-40.
6. At least until 1898 Peirce supported Comte's classification of the sciences according to the order of abstractness of their objects: RLT 114.
7. G. Génova, Charles S. Peirce: La lógica del descubrimiento, Cuadernos de Anuario Filosófico, 45, Pamplona, 1997, 69-76.
Fecha del documento: 9 de enero 2004
Última actualización: 27 de agosto 2009