In: Bott, G.; Willers, J. (Hrsgb.): Focus Behaim-Globus. Referate des internationalen Kolloquiums im Germanischen Nationalmuseum Nürnberg - 5.4.-6.4.1990, Anzeiger des Germanischen Nationalmuseums, Germanisches Nationalmuseum Nürnberg, Nürnberg, April 1991.

At first sight, Martin Behaim's reception at the learned circle of Nürnberg may be considered to have been a reflection of his brother's position in that circle, or of the civic pride and self-interest of many of its members, who, as political, professional and business leaders of the city, stood to profit from putting Nürnberg at the forefront of scientific novelty.

Any of those factors might have played a role in the City Fathers' commission of Behaim's famous globe, and in the lesser known but equally significant insertion of Behaim's account in the 'Liber Chronicarum'. However, with a less cynical and more analytical approach, both events appear to have been manifestations of a scientific attitude well established in the Nürnberg learned circle when Behaim returned to his native city in 1491.

The conception and realization of that remarkable project which was the 'Liber Chronicarum' bore in themselves many traits of that scientific attitude.

The plinth of it was a psychology of man's perceptions, knowledge and actions, and a conception of sience and scientific methodology derived therefrom, which were widely accepted in Nürnberg. The adherance to them is evidenced by the scientific behaviour of numerous members ofthe city's intellectual 'milieu' before, during and after the period under consideration. Two major theoretical sources contributed to the unfolding of that scientific attitude.

The oldest ones were the teachings of an acknowledged number of our Western civilization: the Roman noble, philosopher, poet, statesman and Christian martyr Anicius Manlius Severinus Boëthius (A.D. 470-526).

In that delectable elixir of classical and Christian teachings which was Boëthius's 'De Consolatione Philosophiae' with its heavy accent on the liberty and responsibility of man emphasized by the Christian faith, Boëthius put forward a psychology which stressed the subjective, individual and changing nature of man's perceptions, knowledge and actions.

Published in Nürnberg by Antonius Koberger in 1473 and 1476 (1), superb editions, and again in 1486 (2), 'De Consolatione Philosophiae' was not only one of the greatest books ever written but also one of the most widely read and commented throughout the Middle Ages (3) and the early modern period (4).

Written without the aid of books or notes, whilst Boëthius, unjustly imprisoned by King Theodoric in Pavia, was undergoing physical and psychological tortures, 'De Consolatione Philosophiae' was a poignant book yet one in which the author never lapsed into self-pity. Above all, it was a highly personal and profound synthesis of scholarly knowledge, delivered directly, partly in prose and partly in verse, without scholarly pretensions or digressions, and a deeply felt Christian message which should have reached its apex in a sixth book, if the author would not have been brutally murdered (5).

Those qualities of 'De Consolatione Philosophiae' were all the more evident when it was read alongside its classical and Christian sources (6). This exercise not only rendered Boëthius's book all the more pleasurable but also all the more valuable.

Being in itself the product of reflection and choice between a myriad of often conflicting theories, 'De Consolatione Philosophiae' offered a unique demonstration of the nature of man's knowledge. Having stated in the Liber III that glory and nobility were not objective values but depended on the varying perceptions of people, Boëthius went on to explain the inner workings of the mind in the poem of the same book (7). He gave a fuller explanation of the psychology of man's perceptions and knowledge in the Liber V (8), where he concluded that everything which man knew was not 'perceived by its own nature but of that which comprehends it' (9). The subjective, tentative and homocentric theory of knowledge thus expounded had been consistently used by Boëthius in other equally important and well-known works.

In 'De Musica', which provided the conception of music which dominated the whole of the Middle Ages, Boëthius, who stressed throughout the uppermost importance of theoretical knowledge and took pains to explain its foundations (10)had already warned against the misleading role that the senses might play in man's knowledge if they are allowed to (11). He restated that in a beautiful passage of the 'Metrum Quartum', Liber V of 'De Consolatione Philosophiae', where he acknowledged that the senses could well be a source of stimulus for the mind, but not one of knowledge as such, which was the product of the mind's inner processes (12).

'De Arithmetica', where Boëthius spoke of the dignity of the 'Quadrivio' (13) (undoubtedly a reflection of the importance attached to it for the development of the student's mind), and 'De Geometria' (14), went beyond that. They were a clear example that the very means by which man attempted to apprehend and organize the world around him were themselves a product of the human mind. Boëthius's explanation of the nature of time was an even clearer one. He undertook it in 'De Differentiis Topicis', when Boëthius argued in the Liber II that time, like other measures, was a rational product and a convenience, not a natural thing (15). Boëthius added further in the 'In Librum Aristotelis de interpretatione Commentaria Minora' that the division of time into past, present and future, was merely a reflection of the observer's viewpoint (16). But amidst the bewildering variety of man's times and systems to compose it (obvious to anybody who knew classical history), there was also the unity of God's time, which Boëthius outlined in a short treatise dedicated to his father-in-law, 'Ad Symmachum quo modo Trinitas est unus Deus, et non tres Dii' (17). God of course lived in His time, a perpetual present known only to Him; but this was a notion which was crucial to give a logical foundation to the regularities of the physical world and with it to the existence of physical reality and to the desire to study it.

In 'De Consolatione Philosophiae', Boëthius treated this subject in greater detail. Drawing largely on Plato's account of the creation of the universe in the Timaeus, and probably also on Proclus's commentary of this work, as well as on the Book of Genesis, Boëthius told in the poem of the Liber III how God had purposefully created the world in His own eternal likeness, that is, good, perfect and fair. Furthermore, in order to ensure that the cosmos did not revert to its inchoate state, God had given the world an intelligence, soul, or mind which imitated the Divine Mind and partook of its characteristics. It was the peculiarly apocatastic property of the latter, whose circulating motion is ever uniform, that rendered necessary the circular motion of the planets and the constant course of changing of the seasons, never deviating from the original course and order of duration, so that the effect should resemble its coherent cause (18).

Boëthius's message, therefore, provided not only a philosophical framework to pursue the study of nature and cosmos, but also a religious incentive to do so: if the Creator was present in the Creation, the more man understood the latter, the closer he was going to get to God. There were limits here, of course, limits imposed by Christian dogma and the God-man relationship taught therein, or, examined from another perspective, the limits due to man's psychological make-up, which as Boëthius emphasized, restricted what man could aspire to know with the man-made means at his disposal. But the affirmation that physical reality existed, and that there were God-decreed regularities in the fabric and management of the world rendered its study a sensible intellectual undertaking and almost a religious duty, in order to know God better - a non negligeable feature in an intensely religious age, and one which, in time, turned up to be one of the greatest contributions of Christianity to the development of science (19).

The same message was conveyed a millenium later by the life and work of a towering XVth Century figure, a mathematician, philosopher and theologian who was at the centre of the cultural, diplomatic, political and religious life of his time and was well known to the Nürnberg intellectual 'milieu': the Cardinal Nikolaus von Kues (20).

Like Boëthius, often cited by him and referred to as 'that very wise man' (21), Cardinal Nikolaus von Kues was fuelled by an unbound curiosity and his work rested on three solid pillars: a prodigious knowledge of ancient and contemporary academic sources which was acknowledged and admired (22), a rich and varied life experience and deep religious feelings. He outlined a psychology of man's perceptions, knowledge and actions, and a related theory and methodology of science which, like Boëthius's, attempted to reconcile the classical views on those subjects, and the observation of man and phenomena in the physical and social worlds.

Although permeating throughout his written work and other endeavours (including the scientific questions submitted to Georg von Peurbach and Johannes Müller von Königsberg (Regiomontanus) two of his protégés'), Cardinal Nikolaus von Kues propounded those views specifically in 'De Mente' and in 'De Staticis Experimentis'. Both treatises were written in 1450, published in Nürnberg in 1471, together with the other two dialogues of 'De Idiota', 'De Apice Theoriae', and other works (23).

In 'De Mente', reconciling Plato's and Aristotle's idea of the 'soul of the world' and of 'nature' (24), and their apparently opposite views about the degree of intelligibility God and man were capable of, an argument to which he added elements from other Christian and pagan sources, Boëthius's physiology and his own observations and reflections, Cardinal Nikolaus von Kues put forward a psychology of man's knowledge and a theory of science which was to have a singular effect upon the Nürnberg intellectual 'milieu' and in German and European science in general.

Nikolaus von Kues explained there that in the Supreme Intelligence, conception, will and execution were one and the same thing. God, therefore, did not require an agent to implement his will and design, since the behaviour of every created object was coetaneous with Creation itself. This included Motion, the agent of change from one state to another one (25).

Cardinal Nikolaus von Kues was therefore speaking about a self-contained universe, one which, unlike that depicted by many Greeks, did not require constant overseeing by and intervention of the Creator. His universe was a 'cosmos' in the purest sense of the term, resembling - and perhaps inspired by - the heavenly clockwork of Buridanus and Oresme, which could maintain its regular motions by virtue of the 'creative' impetus imparted to it (26). Man's ability to apprehend that universe at once conditioned and limited man's knowledge.

Having been created in the image of God, man's soul posessed, in essence, the capacity of the trinity of power, wisdom and will which inhered in the Supreme Intelligence, the Creator. Knowledge ensued not from the senses but from an internal, individual and subjective act of judgement of the mind (27). It was the latter which also directed the senses to collect specific data or to transfer the motion to execute its will.

The required motion to generate sound and musical harmony from external objects illustrated that transfer. This motion was the result of an original intellectual motion, transferred through the senses and human action to an external object, such as a piece of glass or a musical instrument (28). Cardinal Nikolaus von Kues referred to the agent of this transfer 'for want of a better name', as the 'spirit of motion' (29).

He explained further the transfer and materialization of man's volition with the example of the glass maker, whose blow confers to the molten glass a shape which existed beforehand in his mind (30). This implied that master and mastery inhered in the human soul as they did in the Supreme Architect. Consequently, this also implied that in measuring the created oject, man was measuring his own creation. Since the notions of number, shape, time and weight were manifest creations of the human spirit (31), it followed that in measuring motion (i.e. 'change') in the universe, man was measuring his own intellectual motions (i.e. 'theories') rather than the actual motions of the universe.

Therefrom ensued real limitations to man's knowledge - and to science. Although man's knowledge and intellect were perfectible, as shown by the development from childhood to adulthood (32), man's soul was incapable of reaching the Creator's perfect intelligibility (33).

Another limitation was more subtle. It was rooted in the limits to the generalization of man's apprehension of phenomena, which is circumscribed by time and circumstances. A good illustration of it was offered by the example of the painter's self-portraits. One of them was as near to perfection as possible, having captured his image at a particular instance of his life. But, as such, it was a 'dead' portrait. The other one was not nearly as perfect, but it had the property of being 'alive', and thereby to follow and reflect the dynamic changes taking place on the painter's face (34). The latter example was of course an impossibility, but it pointed out to man's inability to capture more than a fleeting moment of ongoing phenomena.

In part, this was so because man himself was as much an inextricable part of a dynamic and complex world as the phenomena he endeavoured to understand. Unlike the Blessed Spirits in Heaven, who were able to contemplate the objective truth of each constituent element of the universe in static isolation, the observer in this world was as much in motion as the world was, and overwhelmed by its diversity and accidental phenomena. He lacked, therefore, the perspective vision which could be acquired from a perfectly static viewpoint, and from one which was free from the motion and distraction to which any human observer was subjected to.

In those all too human conditions, the theories constructed to explain observable phenomena could only be imperfect and incomplete, both on account of accidental and variable elements present in all phenomena and of the accidental and variable elements affecting the observer (35).

The means designed by man to observe and evaluate phenomena had, inevitably, those shortcomings. Cardinal Nikolaus von Kues had asserted in 'De Mente' that the making of an instrument was preceeded by the theory of it and that the form of the instrument followed the idea of it (36).

In 'De Staticis Experimentis', he went on to explain further this point and to emphasize the role of theories in man's observations and experiments, and indeed in the foundation of notions such as 'normal' and 'average', which are fundamental to observe and to experiment. Cardinal Nikolaus von Kues stressed in this regard the role that circumstances such as geographical location and climatic conditions had in the formulation of such notions and in the results of observations and experiments (37).

A sensitive observer, as reveal for instance his references in 'De Visione Dei' to a work of art he had seen in Nürnberg or to a painting by Rogier van der Weyden he had seen in Brixen (38), the inclusion of 'De Idiota' and 'Mechanicus' as interlocutors in 'De Mente' and 'De Staticis Experimentis', and the constant reference to examples from every-day life had a clear purpose. Besides denoting the Cardinal's adherence to a doctrine which recognized the benefits that society could derive from them (39), their presence in the treatises underlined the universal nature of man's cognitive processes, regardless of rank or activity, the universal character of the knowledge man was capable of acquiring, and the universal role that observation and experimentation played in his attempts to confuse it or to validate it.

The constant interplay of those factors in the psychology of knowledge was shown over and over in 'De Staticis Experimentis'. A reference to Vitruvius, a man of vast erudition and a bold theoretician, underscored that his architectural work could not have been carried out without having recourse to experiment and practice.

The latter embodied 'experience', the result of observations and experiments sanctioned by use, which, whether acquired or inherited from preceeding generations, was stored in the practitioner's memory and was shown to be a vital step in the formation of knowledge.

The example chosen to do so was accessible to all. By referring to familiar medical practices, Cardinal Nikolaus von Kues was able to render obvious the constant commerce between cogitation, observation and experiment in man's psychological processes. And since the very standards used to determine 'normal' and 'abnormal' conditions in man's health were themselves theoretical and probabilistic, they rendered obvious too the nature of man's knowledge.

Once again, 'De Staticis Experimentis' demonstrated that 'objective knowledge' and 'absolute truth' were not of this world. In 'De Mente', Cardinal Nikolaus von Kues said that the notions that man could acquire in this variable and unstable world could not be fixed in a firm manner. They were like the notions of the students who had not yet acquired the Master's degree. It was only when the particular notions passed to the perfect mastery that in this universal mastery, they lost their variability. But this meant that, in this world, men remained apprentices; it was only in the other world that they became masters (40).

The ineluctable reality of the human condition neither saddened nor deterred the Cardinal. On the contrary, it stimulated him.

In 'De Mente', he explained that man's soul, being a living and perfect image of the Infinite Art, posessed in the unity of its essence the power, wisdom and will, the coincidence of master and mastery, that rendered it capable of becoming nearer the actual Divine Art.

Although in the Cardinal's psychology, no amount of reason could ever explain the soul (41) (one of the fundamental traits it shared with modern theories (42)). And the advantages of man's intuitive inclination to abstract the invariable from the variable and composite phenomena had to be balanced with the dangers of tautology (43), man's soul could, if properly stimulated, progress towards the ideal and, through a better understanding of Creation move closer to the Creator (44). A highly imaginative man, and one with a prodigious energy, Cardinal Nikolaus von Kues personified that attitude.

The dialogue 'De Staticis Experimentis' alone was ample proof of it. Having put forward there a truly 'experimental' method which made not undue claims to being 'objective', the Cardinal proposed to apply it to find out the relationship between volume and weight and to the problems of mass and gravity of metals. He suggested further that the experiments on mass and gravity could be useful to study the trajectory of missiles shot with crossbows and Lombardy guns, proposed a method to measure the depth of water, particularly at sea, speculated that the strength of mass was proportional to gravity and that this relationship could be used to theorize about time, the motions of the celestial bodies and their size (45).

The compass of the Cardinal's scientific interests went from the making of the first modern map of Germany in 1439 to a plan to drain the Pontine swamps and from the formulation of a series of hypotheses about the motions of the universe to a theory of infinity based on the idea of the coincidence of opposites which perhaps owed much to Pliny the Elder (46).

With a spirit which obviously saw and sought the advantages of academic discussion, Cardinal Nikolaus von Kues enjoyed submitting his views to the scrutiny of others. His hypotheses about the earth's motion around the vertical and horizontal axes and the firmament's motion around the earth's axis were publicly debated at the University of Vienna under the chairmanship of Georg von Peurbach, a debate reported by Johannes Schöner in his 'Opusculum Geographicum', published in Nürnberg in 1533. The Cardinal's proposed solution to the old problem of the squaring of the circle was considered by Johannes Müller von Königsberg, better known as Regiomontanus, the Prince of the XVth Century astronomers whose rejection of the Cardinal's proposition was well known (47).

Both Peurbach and Regiomontanus, to whom Cardinal Nikolaus von Kues was a generous maecenas and a stimulating influence, contributed much to the diffusion of the theory and the methodology of science propounded by the Cardinal.

In so doing, they were following as well an approach to science well established in Germany and which, implicitly or explicitly, corroborated the psychology of man's perceptions, knowledge and actions taught by Boëthius and Cardinal Nikolaus von Kues and the theory and methodology of science so brilliantly verbalized by the latter.

Amongst German astronomers that approach was a tradition which went back at least to Heinrich Heinbuche von Langenstein. Tired of the strictures of the University of Paris, von Langenstein went to Vienna, where he worked strenuously towards the reorganization of the University, of which he became Rector in 1391. Amid continuous astronomical observations, von Langenstein insisted on the need to develop the mathematical theory and the instruments required to carry out and to measure them. His successors at the chair of the University of Vienna, Magister Julman, Johannes von Gmunden and Georg von Peurbach, the friend and teacher of Regiomontanus, maintained that tradition alive and built upon it.

Johannes von Gmunden's special trip from Vienna to Lübeck to carry out, with great precision, the first observation of Mercury in Christian Europe on the 24th of August 1432, echoed those made by Heinrich von Langenstein and by Magister Julman to observe astronomical events from the most advantageous European locations. Georg von Peurbach and particularly his disciple, Johannes Müller von Königsberg (Regiomontanus) consolidated that scientific approach.

The Nürnberg City Fathers had the foresight to entice Regiomontanus to settle in the City. He did so in 1471, and in spite of his untimely death in Rome only five years later, in 1476, he left an indelible imprint upon the scientific attitudes, methodology and objectives of the Nürnberg intellectual 'milieu'. A multifaceted genius, Regiomontanus sought to improve at once scientific theory, observation, experimentation and diffusion through the development of mathematical theory (including music), the design and construction of better instruments, a greater attention to the exactness and purity of language, and careful printing.

The Index is a sad reminder of how little he was allowed to accomplish of his projected life work, but it bears witness to the influence he exerted upon his Nürnberg admirers. Werner's and Pirckheimer's editions of Ptolemy's Geography not only were a direct result of Regiomontanus's legacy and works, where he acknowledged use of his notes was made, but, indirectly also of the inspiration of Cardinal Nikolaus von Kues, who had encouraged Regiomontanus to undertake the editing, correction and updating of Ptolemy's work.

Bernhard Walther, the disciple and friend maecenas of Regiomontanus in Nürnberg, continued Regiomontanus's program of astronomical observations in and out of the city, and on 16th July 1484 he was the first to use a mechanical clock to measure the difference between the rising of Mercury and the Sun. The numerous trips carried out by Johannes Werner, Conrad Heinvogel and Georg Hartmann to make observations on magnetism and the weather, and in order to perfect the theory on those subjects and capabilities, design, and use of the meteoroscope and other instruments to determine land locations and distances via astronomical observations, can also be traced to the legacy of Regiomontanus and the scientific outlook represented by him. The same may be said of Erhard Etzlaub's first map of Nürnberg and neighbouring district made in 1491, and the first roadmap of Germany, which he completed in 150l. Both were part of the general cartographical renewal that Regiomontanus announced in the Index, undoubtedly inspired by Cardinal Nikolaus von Kues who, as already stated, had made or commanded the first modern map of Germany in 1439. Similar influences - and also most likely, that of Pope Pius II, the Cardinal's friend and kindred spirit - were noticeable in Conrad Celtis's 'Urbis Norimbergae Descriptio'. Written in 1492 and incorporated into the 'Liber Chronicarum', Celtis's description was a skilful blend of tradition, history and freely reported contemporary conditions and institutions. Celtis revealed himself there as a penetrating and sensitive observer, qualities abundantly shown later in `De Hercynia Silvae', a masterly description of the Herz's orography which was to open a new path in descriptive geography, and also in his drawings of cities, the first made directly from nature, which appeared in the 'Liber Chronicarum'.

This remarkable book, which I have examined in detail elsewhere (48), was itself a blend of the old and the new. Hardly surprising, given the scope of the work, the admixture was not as successful as in Celtis's 'Urbis Norimbergae Descriptio', but it came about just as naturally.

Nothing could be more eloquent in this regard that Behaim's account of the discovery of unknown islands by the Portuguese under the auspices of Prince Henry, the description of Madeira and its sugar production and exports to Flanders, and the voyages of Diogo Cão (49).

The laconism of Behaim's account runs counter to the view of those who regard the Great Geographical Discoveries of the XVth and XVIth Century as a 'dramatic' event in the development of Western man and science; but it was in full accord with the compilers' perception of man and knowledge.

The 'Liber Chronicarum' aimed at showing the unfolding of the world, but the compilers were aware that, although perfectible, man's knowledge was bound to remain theoretical and incomplete, that theories once spoused by thoughtful men had come and gone ouf of fashion and that what might have appeared at the time to be solid doctrines, were often the outcome of diversity and controversy (50). Behaim's globe was the epitome of that perception of man's knowledge. The globe was a bold and imaginative attempt to provide a visual synthesis of conflicting theories and loose information, some of which was the fruit of Behaim's personal observation (51). If Schedel's note, never appended to the globe, was an indication of that discriminating effort, one can see how much zeal and energy was devoted to that endeavour. The extent of that effort can also begathered from the letter to King João II of Portugal, written by Hieronymus Münzer, one of the compilers of the 'Liber Chronicarum' who had helped Behaim in the making of the globe (52). As such, Behaim's globe portrays vividly the scientific attitudes of the Nürnberg intellectual 'milieu'; scientific attitudes which, as suggest a comparison between the reception given to Behaim and to other capable men lacking his social connections (53), must have accounted largely for his acceptance at the learned circles of Nürnberg.

At once old and 'modern' where examined from our own perspective viewpoint (54), that scientific attitude was seldom verbalized in the Nürnberg learned circle. But when some of its members spoke about their theory and methodology of science, as Schöner and Hartmann were to do (55), they manifested, implicitly or explicitly, the adherance to a psychology of man's perception, knowledge and actions identical to that on which Cardinal Nikolaus von Kues had based his own theory and methodology of science.

Encouraging individual thinking and a constant commerce between theoretical formulation and the observation of the world, this perceptual framework stimulated the development of the technical means to do so. Thus, it was instrumental to making of Nürnberg a leading scientific and technical centre during the XVth and XVlth century and one playing a key role in the transfer of information and new ideas (56).

Fittingly, Martin Behaim, a son of Nürnberg, credited by João de Barros with the introduction of the works of Regiomontanus into Portugal (57), contributed to those exchanges in both ways. This son of Nürnberg, a city described by Willibald Pirckheimer as 'totius Europae umbilico', was a valuable intermediary in the constant flux and reflux of ideas and information which characterize the unfolding of Western Science, culture and civilization. Behaim the man is, regrettably, little known. But his globe bears witness to that process, to his contribution and to the receptivity, the forward looking spirit and the scientific attitudes of his native city's intellectual 'milieu'.

Notes