Born in 1401 as the son of a German boatman at Cusa on the banks of the Moselle some twenty miles from the present Luxembourg border, he took part in the Conciliar movement of the fifteenth century, engaged the redoubtable Torquemada in debate, became converted to the Papal party, travelled to Byzantium as Papal envoy to negotiate for the reunion of the Eastern Church with Rome, was appointed Cardinal in 1448 and Bishop of Brixen in 1450, and died on August 11th, 1464 after an active and often stormy life of Churchman and ecclesiastical reformer. The present article, however, will not deal with his services to the Church, considerable as they were, but only with some aspects of his work as philosopher and scientist.
That Cusanus was, on any reckoning, a remarkable intellectual figure can be seen from the following facts about his life. He was educated among the “Brothers of the Common Life” at Deventer, that centre of holy living founded by Gerard Groote, the friend of Ruysbroeck, to which the world owes one of its greatest spiritual classics, the Imitation of Christ. Throughout his immensely active and practical life, Cusanus remained at heart a contemplative, valued by his contemporaries chiefly as an authority on the mystical writers of the past, and accorded by Evelyn Underhill his “right to a place among the great teachers of the contemplative life”.
Later he went to Heidelberg, already astir with the “new physics” proclaimed by the Ock- hamists, and then for six years to Padua, where he studied, besides Canon Law, geometry, medicine and astronomy. Here, also, he mingled with the men of the early Renaissance: and if his self-styled “barbaric” Latin prose shows few discernible signs of the influence of Petrarch, it was from this time that his reputation as a manuscript-hunter, amateur classical philologist and collector of scientific instruments began. He later turned his mathematical and astronomical studies to excellent account. His own works on these subjects were to be studied by Copernicus, and several decades before the latter he put forward the “grounded hypothesis” that both the earth and the sun were moving, that the earth was of the form of an irregular sphere, and that it revolved on its axis while at the same time moving along an elliptical path.
His thought broke clean through the geo-centric world-view of Mediaeval tradition, and he represented the universe as potentially indefinite (not infinite) in extent, composed throughout of particles in relative motion. His speculations on the identity of the line and the curve when either infinitely great or infinitely small were a step in the chain leading to the eventual discovery of analytical geometry and the calculus.
Besides his many works on philosophy and speculative mysticism, he wrote much on mathematics, a work called Experiments in Statics, treatises on optics and mapmaking and a reformed Calendar, several works on political theory, Canon Law and Dogmatic Theology, and, after travelling about to find the leading Arabists of the day, a treatise on the Koran in which he tried to harmonize the latter with Christian doctrine. This catalogue represents but a small part of Cusanus’s literary output, which was for the most part thrown off at odd moments in the course of continuous preaching and the strenuous and conscientious fulfilment of various offices in the Church. Let us now ton to examine some of the philosophical opinions of this remarkable man.
The dominant world-view in Cusanus’s day was still the Aristotelian, transposed into a Christian setting. The cosmos was taken to consist in a closed spherical system of which the earth was the unmoving centre. The space beyond the moon was held to be occupied by a finite series of eternally revolving spheres, with the earth for their common centre. Beyond these lay the heavenly intelligences. Beyond them God. The heavenly spheres and the heavenly intelligences were taken to form a continuous hierarchy, each link in which contained all the perfections of the one below “eminently”, so that God and the cosmos formed a compact continuous causal system.
Broadly speaking, it was held by most thinkers that the existence of this hierarchy of being was subject to rational demonstration. The lowest sphere in the system, the earth beneath the moon, was exceptional in containing a large fortuitous element that eluded the grasp of reason. But even here elements of fixity, law, order and identity could be found, and it was precisely from these elements that human reason must begin its work.
Before Cusanus’s day, Ockham and his followers, like certain earlier thinkers, had begun to cut at the root of this system by questioning the power of the mind to form genuine universal concepts that corresponded to elements of universality and identity in the objective world. Cusanus was familiar with these arguments, but his own way of thinking was original. What he principally objected to was the notion that God could in any way be brought down into the system of human concepts.
The official scholastic philosophy did not technically admit that God could be comprehended under a concept, but was nevertheless prone to make Him a link in chains of reasoning about the world. Cusanus, however, was particularly zealous to preserve the utter transcendence of God. He was the first man to apply the term “absolute” regularly and systematically to God. “Between the infinite and the finite”, he said, “there is no common measure”. If our thinking starts from empirical premises, it must remain ever within the realm of the finite. A further inference based on a finite thought must itself be finite or it could not stand in any intelligible relation to its predecessor.
Consequently we have not the right to assume that our rational thought can establish a continuous hierarchy of principles that can bridge the gulf between absolute being and empirical being. The only relation that can be said to subsist between the conditioned realm and the unconditioned is that of total mutual exclusion. The only predicates that fit the Absolute are negations of empirical predicates.
This “negative path” in the approach to God was, of course, nothing new in itself. It is found in many of the great schoolmen, including St. Thomas Aquinas himself. But from the standpoint of Cusanus, here doubtless influenced by Ockham and his school, the earlier thinkers had been insufficiently critical in assuming that there was also an affirmative path which gave us rational knowledge of a hierarchical structure in Being. For the Cusan, our thoughts can never be identical with the things they are thoughts of.
For they are thoughts and the things things. But if our thoughts are only like things, other thoughts could be had more like the things, and yet other thoughts yet more like the things and so to infinity. Our thought relates to truth like a polygon to a circle. One may increase the sides in a polygon as much as one will, but as long as it remains a polygon it will never coincide with a circle.
Cusanus held that all human knowledge is conjecture. It consists in hypotheses which will certainly be supplanted By better hypotheses one day. If the human mind approaches certainty anywhere, however, it is in the realm of mathematics. If we do not insist too much on fancied qualitative distinctions, which depend on fallible sense-experience and cannot be rationally justified, the mind is left free to interpret the cosmos as due to quantitative distinctions arising in the distribution of four basic all-pervasive elements, earth, air, fire and water. On this basis, clearly conceived as a merely hypothetical one, Cusanus liberated cosmology from bondage to the closed Aristotelian system of concentric spheres.
The universe, he held, is limited in actual realization at any given point in time but capable of indefinite expansion. Moreover, since there can be no perfect sphere in the empirical realm it is useless to search for the centre of the universe by intellectual means, let alone to posit the earth as that centre. The centre of the universe is God, who can be discovered only by spiritual means.
It is evident that a Christian philosophy worked out on the lines suggested by Cusanus would be likely to come closer to Advaita Vedanta than the traditional Thomism or Augus- tinianism. For the traditional Christian philosophy seeks the structure of the universe in a hierarchy of eternal intelligible forms. Matter is here the principle of change, and it acquires fixity and real being only so far as it participates in the eternal forms. Matter is taken by St. Thomas and St. Augustine alike as “almost nothing” (prope nihil), and that which confers being on the individual substance is its participation in this or that eternal form.
Cusanus offers a different hypothesis, in which less stress is laid on fixed, static and eternal forms. He understands the divine creativity on the analogy of the creativity of the human mind as he conceives the latter. Human knowledge, for him, never results from the copying of any prototype. All necessity in human knowledge comes from within and unfolds itself in the course of the free activity of the mind. The mind attains truth only when it unfolds its own nature. It finds the simple concept of the point not in external nature but in itself. It creates the line by continuous repetition of the point, and the surface by juxtaposition of lines, and the entire world of extension by juxtaposition of surfaces. Similarly, it finds in itself the simple thought of “now”, and from this simple idea of “now” it constructs time as an indefinite series.
As source and origin of knowledge, the mind is not in time: rather, time is in the mind. Time in its “pure” undifferentiated state lies locked up in the “now” of the mind, and the mind introduces its own creative distinctions into what is in itself simple and so itself creates discrete portions of time—hours, months and years. The mind interprets the given manifold through the instrument of discrete intervals of time and space, its own creations. And while careful to point out that we have no knowledge of the manner of God’s creation, Cusanus offered the hypothesis that God allowed the distinctions of the real objective finite world to proceed from His own simplicity on the analogy of the mind unfolding distinctions in time and space. Thus on Cusanus’s view the individual mind creates its own imaginary universe by its imaginative power, or kalpana as the Advaitins would say.
And he assumed that God possesses a remotely comparable power of kalpana whereby He unfolds the Divine simplicity into the objects of the world without Himself undergoing real change. And Cusanus stresses the imaginary character of this process by affirming that the objects of the world are real only so far as they participate in the unity of the Divine Source, not in so far as they are characterized by multiplicity and distinction.
The breach with the past here lies in the rejection of the theory that the element of reality in the world lies in its participation in a hierarchically organized plurality of fixed eternal forms, the real kinds, which can be rationally determined. And it is a change which breaks down many of the barriers separating the traditional Christian philosophy from Advaita Vedanta on the one hand and from modem scientific conceptions on the other.
In regard to the doctrine of the knowledge of God, the similarities between Cusanus’s views and those of Advaita Vedanta are perhaps less striking. Cusanus lays stress on the inner vision. But he does not admit that God can be known either perfectly or continuously by the individual mind. Wherever and whenever a man looks inwards towards God he sees Him, but his view of Him is momentary and imperfect, is conditioned partly by the time and place and partly also by his own state of mind. A man’s relationship with God, however, is so immediate that it cannot be expressed in direct language, in particular, cannot be spoken of in quantitative terms, such as part and whole. Any glance directed inward which sees God sees nothing but itself, because it sees its own “truth”, its svarupa as the Advaitins would say, but sees it distorted.
Hence the different visualizations of God current among men. The deepest phase of knowledge of God, however, is when there is no consciousness either of a self or of another, when there is “no more knowledge or conceiving”. In this experience human knowledge attains to awareness of its ignorance of the Absolute. It does not positively comprehend the Absolute. But it comprehends once and for all that, as finite, it is “other than” the Absolute.
This is the only sense in which the Absolute can come into relation with human knowledge. The “otherness” of the Absolute includes a relation with the negative pole of human knowledge. Without this relation, human knowledge could not comprehend its own nullity. And Cusanus anticipated the doctrine advanced by Hegel to contravert Kant’s agnostic view of the limitations of the theoretical reason, the doctrine, namely, that the mind could not prescribe its own limits unless in some sense it already had knowledge beyond those limits. Awareness of difference includes the mediation of that which is different. But this mediation does not imply that infinite Being enters into relation with empirical consciousness. A universal Self must be posited beyond the empirical self to account for the relation of the latter with the Absolute.
And this universal Self which mediates between the Absolute and the empirical realm was identified by Cusanus with Christ, an eternal principle indwelling in man. Individual man, however, does not attain to perfect union with the Absolute. For all the Cusan’s admiration for Eckhart, he does not reproduce the latter’s characteristic doctrine that the miracle of God becoming man did not occur in past time but must occur and can only occur in the eternal “now” of the individual soul.
Cusanus was firmly imbued with the conviction of the relativity of all positive conceptions of God. A large part of his practical life was devoted to working for reconciliation between the Eastern and Western Churches and between Christianity and Islam. In his De Pace Fidei he shows that the Absolute, itself unintelligible to the finite intellect, can only be known to the intellect under distorted forms. From this it follows that, since it is itself unity, it can only be conceived under a plurality of different forms. Here the different religions with their varying conceptions of God are not merely “tolerated”. Their presence is epistemologically grounded and made the subject of speculative demand.
As a German who had lived and travelled extensively in Italy, Cusanus was exposed to influence from the two greatest mystical traditions of his day. In St. Francis of Assisi there had arisen a new Christian ideal of life which broke the stark antithesis of “nature” and “spirit”. Here love is no longer, as among some of the earlier mediaeval mystics, directed exclusively towards God as the transcendent ground of being. Nor is it exclusively directed towards man, according to the ideals of later humanistic ethics. It is directed, in a manner reminiscent of Indian spirituality, towards all creatures as such—animals and plants, sun and moon, the elements and the elemental powers.
The latter are not regarded as so many “parts” of being. In the heat of mystical love, they are soldered to unity with God and man. The mystical category of brotherhood breaks down the logical categories of species and individual, in the light of which nature had previously been divided into different kinds and arranged in a hierarchy of different grades. Trees and flowers, wind and water, as well as fish and birds become “brothers and sisters of man” for St. Francis. Here the Middle Ages begins the great work of liberating nature from the stigma of sin and sensuality.
But so far we have merely the feeling of love at work, without any corresponding advance in knowledge. Cusanus sought a speculative justification of nature, but not in terms of the old Aristotelian logic of genus and species. He saw nature as a symbol of the Divinity. But what he asked of a symbol was not so much force and liveliness as clarity and certitude. “Nature”, he wrote, “is the book in which God has written with His own hand”. But he did not believe that the meaning of that book could be understood through mere subjective mystical feeling. It must be investigated, riddled out word for word and letter for letter. And the proper instrument for this task is mathematics.
Only mathematics can set up the standard of necessity which rules out the arbitrariness and uncertainty of personal feeling and opinion. Leonardo da Vinci, who has been proved to have been directly dependent on Cusanus here and the link between him and Galilei and Kepler, wrote “whoso despises the exactitude of mathematics, feeds his mind on confusion”.
Cusanus maintained that all science is nothing other than the unfoldment of what lies in the mind. Here he pointed to the modem conception not only of logic, mathematics and natural science, but also of technology and of invention as proceeding from technological advance. The mind unfolds space from the principle of the point lying within it, and time from the principle of the “now”. And in the same way, all the acts by which it seeks to control nature must be preceeded by some form of ideal projection.
All arts and skills are rooted in creative projections of this kind. And Cusanus expressly says that the categories of logic, the concepts of geometry and arithmetic, the compositions of music, the discoveries of astronomy and also the technical inventions of the scientist are to be regarded as evidence of the independence and eternity of the human mind. For when it is said that man is made in the image of God, the sole point of likeness is the mode of their creative activity.
The Absolute bears no proportion with the finite, and God and man are similar neither in their nature nor in the results of their acts. The mind of man cannot be a mere copy of God or it would be dead. It acquires the form of life in that it agrees with its Divine Source in point of productive activity. And the proof of the specific perfection of the mind of man is that it halts at no particular goal. Here Cusanus provided the “Faustian” mood of the Renaissance with its deepest philosophical justification. The drive towards the infinite is not taken as hubris on the part
of the mind but as the mark of its divine calling and indestructibility.
Before Cusanus died he made provision for scholarships for twenty poor students and built a charitable home at Cues to house thirty poor people over the age of fifty. The home has now become a national heirloom, and houses his library and scientific instruments. The library consists largely of the works of St. Augustine and Dionysus and many pages of Eckhart’s works, well annotated by Cusanus in the margin. Deeply rooted in the great mystical writers of the past, his thought looked out into the future.
His mathematical thought had direct influence on Copernicus and Leonardo, and indirect influence on Galilei, Kepler and Descartes. His cosmological and metaphysical ideas were broadcast in a distorted form and without adequate acknowledgement by Bruno, through whom he influenced Spinoza, Leibniz, Goethe and Schelling. In certain aspects of his thought he even looks forward to Kant and Hegel. An extremely exalted view of his place among European philosophers can only be taken if one keeps one’s eye firmly fixed on the form of his system, making generous allowances for its comparative poverty of empirical content. But whatever the final estimate of Cusanus as a thinker, one thing is certain.
And that is that he provides an example of how a man whose main aim in life is the practice of the presence of God and whose chief study and delight are the mystical writers of the past can yet make contributions to the scientific and philosophic thought of his age that go immeasurably beyond that of any other individual. And it is perhaps not altogether without significance and interest that the system he contrived has clear affinities both with Advaita Vedanta and modem science.