Ernst Cassirer occupies a unique place in twentieth-century
philosophy. His work pays equal attention to foundational and epistemological issues in
the philosophy of mathematics and natural science and to aesthetics, the philosophy of
history, and other issues in the "cultural sciences" broadly conceived. More
than any other German philosopher since Kant, Cassirer thus aims to devote equal
philosophical attention both to the (mathematical and) natural sciences (Naturwissenschaften)
and to the more humanistic disciplines (Geisteswissenschaften). In this way,
Cassirer, more than any other twentieth-century philosopher, plays a fundamental mediating
role between C. P. Snow’s famous "two
cultures." He also plays a similarly mediating role between the
two major traditions in twentieth-century academic philosophy — the
"analytic" and "continental" traditions— whose radically
different (and often mutually uncomprehending) perspectives on the relationship between
scientific and humanistic elements in their subject gave rise to a fundamental split or
gulf between philosophy as it came to be practiced in the Anglo-American world, on the one
side, and as it was practiced in most of the rest of the world, on the other. Cassirer, by
contrast, had fruitful philosophical relations with leading members of both traditions
— with Moritz Schlick, the founder and guiding spirit of the Vienna Circle of logical
empiricists, whose work in logic and the philosophy of science had a decisive influence on
the development of philosophy in the United States, and with Martin Heidegger, the creator
of a radical "existential-hermeneutical" version of Husserlian phenomenology
which quickly became dominant in continental Europe.

Cassirer was born on July 28, 1874, to a wealthy and cosmopolitan
Jewish family, in the German
city of Breslau (now Wroclaw, Poland). Part of the family lived in Berlin, including
Cassirer’s cousin Bruno Cassirer, the distinguished publisher, who later published most of Cassirer’s writings.
Cassirer entered the University of Berlin in 1892. In 1894 he took a course on Kant with
Georg Simmel, who recommended Hermann Cohen’s writings on Kant in particular. Cohen, the
first Jew to hold a
professorship in Germany, was the founder of the so-called Marburg School of neo-Kantianism, famous for interpreting Kant’s transcendental method as
beginning with the "fact of science" and then arguing regressively to the
presuppositions or conditions of possibility of this "fact." Kant was thus read
as an "epistemologist [Erkenntniskritiker]" or methodologist of science
rather than as a "metaphysician" in the tradition of post-Kantian German
idealism. After learning of Cohen’s writings from Simmel, Cassirer (then nineteen years old) proceeded to devour them, whereupon he
immediately resolved to study with Cohen at Marburg. He studied at Marburg from 1896 to 1899, when he completed his
doctoral work with a dissertation on Descartes’s analysis of mathematical and natural
scientific knowledge. This appeared, in turn, as the Introduction to Cassirer’s first
published work, a treatment of Leibniz’s philosophy and its scientific basis [Cassirer
1902]. Upon returning to Berlin in 1903, Cassirer further developed these themes while
working out his monumental interpretation of the development of modern philosophy and
science from the Renaissance through Kant [Cassirer 1906, 1907a]. The first volume of this
work served as his habilitation at the University of Berlin, where he taught as an
instructor or Privatdozent from 1906 to 1919.

In 1919 Cassirer was finally offered professorships at two newly founded universities
at Frankfurt and Hamburg under the auspices of the Weimar Republic. He taught at Hamburg
from 1919 until emigrating from Germany in 1933. During these years Cassirer completed his
three-volume Philosophy of Symbolic Forms [Cassirer 1923, 1925, 1929b], which
broke fundamental new ground beyond the neo-Kantianism of the Marburg School and
articulated his own original attempt to unite scientific and non-scientific modes of
thought ("symbolic forms") within a single philosophical vision. In 1928
Cassirer offered a defense of Weimar [Cassirer 1929a] at the University’s celebration of
the tenth anniversary of the Republic, and in 1929-30 he served as the rector of the
University, as the first Jew
to hold such a position in Germany. In the Spring of
1929 Cassirer took part in a famous disputation with Martin Heidegger in Davos,
Switzerland, where Heidegger explicitly took Cohen’s neo-Kantianism
as a philosophical target and defended his radical new conception of an "existential
analytic of Dasein" in the guise of a parallel interpretation of the philosophy of
Kant [Heidegger 1929]. Cassirer, for his part, defended his own new understanding of Kant
in the philosophy of symbolic forms — against Heidegger’s insistence on the
ineluctability of human finitude — by appealing to genuinely objectively valid,
necessary and eternal truths arising in both moral experience and mathematical natural
science. Nevertheless, despite their deep disagreements, Cassirer and Heidegger enjoyed
friendly philosophical relations until Cassirer’s emigration in 1933 (see [Friedman
2000]).

After his emigration Cassirer spent two years lecturing at Oxford and then six years at
the University of Göteborg in Sweden. During this time he developed his most sustained
discussion of morality and the philosophy of law as a study of the Swedish legal
philosopher Axel Hägerström [Cassirer 1939] (see [Krois 1987, chap. 4]). He also
articulated his major statement on the relationship between the natural sciences and the
"cultural sciences" [Cassirer 1942], which contained, among other things, an
explicit rejection of Rudolf Carnap’s "physicalism" (see [Friedman 2000, chap.
7]). Cassirer, like so many German émigrés during this period (including Carnap) then
finally settled in the United States. He taught at Yale from 1941 to 1944 and at Columbia
in 1944-45. During these years he produced two books in English [Cassirer 1944, 1946],
where the first, An Essay on Man, serves as a concise introduction to the
philosophy of symbolic forms (and thus Cassirer’s distinctive philosophical perspective)
as a whole and the second, The Myth of the State, offers an explanation of the
rise of fascism on the basis
of Cassirer’s conception of mythical thought. Two important American philosophers were
substantially influenced by Cassirer during these years: Arthur Pap, whose work on the
"functional a priori" in physical theory [Pap 1946] took shape under Cassirer’s
guidance at Yale, and Susanne Langer, who promulgated Cassirer’s philosophy of symbolic
forms in aesthetic and literary circles (see, e.g., [Langer 1942]). Cassirer’s American
influence thus embraced both sides of his philosophical personality. One can only
speculate on what this influence might have been if his life had not been cut short
suddenly by a heart attack while walking on the streets of New York City on April 13,
1945.

As indicated above, Cassirer’s first writings were largely historical in character
— including a discussion of Leibniz’s philosophy in its scientific context [Cassirer
1902] and a large-scale work on the history of modern thought from the Renaissance through
Kant, Das Erkenntnisproblem in der Philosophie und Wissenschaft der neueren Zeit
[Cassirer 1906, 1907a]. The latter, in particular, is a magisterial and deeply original
contribution to both the history of philosophy and the history of science. It is the first work, in fact, to develop a detailed reading of
the scientific revolution as a whole in terms of the "Platonic" idea that the
thoroughgoing application of mathematics to nature (the so-called mathematization of
nature) is the central and overarching achievement of this revolution. And Cassirer’s
insight was explicitly acknowledged by such seminal intellectual historians as E. A.
Burtt, E. J. Dijksterhuis, and Alexandre Koyré, who developed this theme later in the
century in the course of establishing the discipline of history of science as we know it
today (see, e.g., [Burtt 1925], [Koyré 1939], [Dijksterhuis 1959]). Cassirer,
for his part, simultaneously articulates an interpretation of the history of modern
philosophy as the development and eventual triumph of what he calls "modern
philosophical idealism." This tradition takes its inspiration, according to Cassirer,
from idealism in the Platonic sense, from an appreciation for the "ideal" formal
structures paradigmatically studied in mathematics, and it is distinctively modern in
recognizing the fundamental importance of the systematic application of such structures to
empirically given nature in modern mathematical physics — a progressive and synthetic
process wherein mathematical models of nature are successively refined and corrected
without limit. For Cassirer, it is Galileo, above all, in opposition to both sterile
Aristotelian-Scholastic formal logic and sterile Aristotelian-Scholastic empirical
induction, who first grasped the essential structure of this synthetic process; and the
development of "modern philosophical idealism" by such thinkers as Descartes,
Spinoza, Gassendi, Hobbes, Leibniz, and Kant then consists in its increasingly
self-conscious philosophical articulation and elaboration.

In explicitly embracing late nineteenth-century work on the foundations of mathematics,
Cassirer comes into very close proximity with early twentieth-century analytic philosophy.
Indeed, Cassirer takes the modern mathematical logic implicit in the work of Dedekind and Hilbert, and explicit in the
work of Gottlob Frege and the early Bertrand Russell, as providing us with our primary tool for moving beyond the empiricist
abstractionism due ultimately to Aristotelian syllogistic. The modern "theory of the
concept," accordingly, is based on the fundamental notions of function, series, and
order (relational structure) — where these notions, from the point of view of pure
mathematics and pure logic, are entirely formal and abstract, having no intuitive
relation, in particular, to either space or time. Nevertheless, and here is where Cassirer
diverges from most of the analytic tradition, this modern theory of the concept only
provides us with a genuine and complete alternative to Aristotelian abstractionism and
philosophical empiricism when it is embedded within the genetic conception of knowledge.
What is primary is the generative historical process by which modern mathematical natural
science successively develops or evolves, and pure mathematics and pure logic only have
philosophical significance as elements of or abstractions from this more fundamental
developmental process of "productive synthesis" aimed at the application of such
pure formal structures in empirical knowledge (see especially [Cassirer 1907b]).

Cassirer’s assimilation of Einstein’s general theory of relativity marked a watershed
in the development of his thought. It not only gave him an opportunity, as we have just
seen, to reinterpret the Kantian theory of the a priori conditions of objective experience
(especially as involving space and time) in terms of Cassirer’s own version of the genetic
conception of knowledge, but it also provided him with an impetus to generalize and extend
the original Marburg view in
such a way that modern mathematical scientific knowledge in general is now seen as just
one possible "symbolic form" among other equally valid and legitimate such
forms. Indeed, [Cassirer 1921] first officially announces the project of a general
"philosophy of symbolic forms," conceived, in this context, as a philosophical
extension of "the general postulate of relativity." Just as, according to the
general postulate of relativity, all possible reference frames and coordinate systems are
viewed as equally good representations of physical reality, and, as a totality, are
together interrelated and embraced by precisely this postulate, similarly the totality of
"symbolic forms" — aesthetic, ethical, religious, scientific — are
here envisioned by Cassirer as standing in a closely analogous relationship. So it is no
wonder that, subsequent to taking up the professorship at Hamburg in 1919, Cassirer
devotes the rest of his career to this new philosophy of symbolic forms. (Cassirer’s work
in the philosophy of natural science in particular also continued, notably in [Cassirer
1936].)

At Hamburg Cassirer found a tremendous resource for the next stage in his philosophical
development — the Library of the Cultural Sciences founded by Aby Warburg. Warburg was an eminent art historian
with a particular interest in ancient cult, ritual, myth, and magic as sources of
archetypal forms of emotional expression later manifested in Renaissance art, and the
Library therefore contained abundant materials both on artistic and cultural history and
on ancient myth and ritual. Cassirer’s earliest works on the philosophy of symbolic forms
appeared as studies and lectures of the Warburg Library in the years 1922-1925, and the
three-volume Philosophy of Symbolic Forms itself appeared, as noted above, in
1923, 1925, and 1929 respectively. Just as the genetic conception of knowledge is
primarily oriented towards the "fact of science" and, accordingly, takes the
historical development of scientific knowledge as its ultimate given datum, the philosophy
of symbolic forms is oriented towards the much more general "fact of culture"
and thus takes the history of human culture as a whole as its ultimate given datum. The
conception of human beings as most fundamentally "symbolic animals," interposing
systems of signs or systems of expression between themselves and the world, then becomes
the guiding philosophical motif for elucidating the corresponding conditions of
possibility for the "fact of culture" in all of its richness and diversity.

Characteristic of the philosophy of symbolic forms is a concern for the more
"primitive" forms of world-presentation underlying the "higher" and
more sophisticated cultural forms — a concern for the ordinary perceptual awareness
of the world expressed primarily in natural language, and, above all, for the mythical
view of the world lying at the most primitive level of all. For Cassirer, these more
primitive manifestations of "symbolic meaning" now have an independent status
and foundational role that is quite incompatible with both Marburg neo-Kantianism and Kant’s original
philosophical conception. In particular, they lie at a deeper, autonomous level of
spiritual life which then gives rise to the more sophisticated forms by a dialectical
developmental process. From mythical thought, religion and art develop; from natural
language, theoretical science develops. It is precisely here that Cassirer appeals to
"romantic" philosophical tendencies lying outside the Kantian and neo-Kantian
tradition, deploys an historical dialectic self-consciously derived from Hegel, and comes
to terms with the contemporary Lebensphilosophie
of Wilhelm Dilthey, Henri Bergson, Max Scheler, and Georg Simmel — as well as with the
closely related philosophy of Martin Heidegger.

The distinction between appearance and reality, as expressed in the propositional
copula, then leads dialectically to a new task of thought, the task of theoretical
science, of systematic inquiry into the realm of truths. Here we encounter the third and
final function of symbolic meaning, the significative function (Bedeutungsfunktion),
which is exhibited most clearly, according to Cassirer, in the "pure category of
relation." For it is precisely here, in the scientific view of the world, that the
pure relational concepts characteristic of modern mathematics, logic, and mathematical
physics are finally freed from the bounds of sensible intuition. For example, mathematical
space and time arise from intuitive space and time when we abstract from all demonstrative
relation to a "here-and-now" and consider instead the single system of relations
in which all possible "here-and-now"-points are embedded; the mathematical
system of the natural numbers arises when we abstract from all concrete applications of
counting and consider instead the single potentially infinite progression wherein all
possible applications of counting are comprehended; and so on. The eventual result is the
world of modern mathematical physics described in Cassirer’s earlier scientific works
— a pure system of formal relations where, in particular, the intuitive concept of
substantial thing has finally been replaced by the relational-functional concept of
universal law. So it is here, and only here, that the generalized and purified form of
(neo-)Kantianism distinctive of the Marburg School gives an accurate characterization of human thought. This
characterization is now seen as a one-sided abstraction from a much more comprehensive
dialectical process which can no longer be adequately understood without paying equal
attention to its more concrete and intuitive symbolic manifestations; and it is in
precisely this way, in the end, that the Marburg "fact of science" is now firmly
embedded within the much more general "fact of culture" as a whole. (The final
volume of The Philosophy of Symbolic Forms, The Phenomenology of Knowledge
[1929b], articulates this embedding most explicitly, where the significative function of
symbolic meaning is depicted as dialectically evolving — in just the sense of Hegel’s
Phenomenology of Spirit — from the expressive and representative functions.)

As noted above, in the same year (1929) that the final volume of The Philosophy of
Symbolic Forms appeared, Cassirer took part in an historically significant encounter
with Martin Heidegger in Davos — where, in particular, Cassirer
challenged Heidegger’s radical "finitism" by reference to the presumed necessary
(and eternal) universal validity found in both the mathematical sciences and human moral
or practical experience. Heidegger had already distanced his own "existential
analytic of Dasein" from Cassirer’s analysis of mythical thought in Being and
Time (see [Heidegger 1927, §§ 10, 11]), and he had then published a respectful but
critical review of Cassirer’s volume on mythical thought [Heidegger 1928]. Cassirer, for
his part, added five footnotes on Being and Time before publication of his final
volume in 1929, and he then published a similarly respectful but critical review of
[Heidegger 1929] alluding to the Davos disputation at the end [Cassirer 1931]. Unlike in his remarks at the Davos disputation itself, Cassirer here
places his primary emphasis on the practical and aesthetic dimensions of Kant’s thought,
as expressed in the Critique of Practical Reason and the Critique of
Judgement. His main point is that, whereas the transcendental analytic of the Critique
of Pure Reason may indeed be written from the point of view of human temporality or
finitude, the rest of the Kantian system embeds this particular theory of human cognition
within a much wider conception of "the intelligible substrate of humanity."
Cassirer’s remarks here thus mirror his own attempt to embed the Marburg genetic conception of
mathematical-scientific knowledge within a much wider theory of the development of human
culture as a whole, and thereby reflect, as indicated at the beginning, his distinctive
mediating role between the Naturwissenschaften and the Geisteswissenschaften
— and thus between the analytic and continental philosophical traditions.

My aim, in this brief hour, is to share with you a glimpse I was privileged to get of
the landscape of two great minds, Tillich and
Einstein. In different but parallel ways, they both reached out to
the limits of human understanding, driven by what Tillich
called Ultimate Concerns. Their ambitions were so enormous that, in
the end, neither had fully succeeded. Yet, each left us an invaluable legacy, and perhaps
also a lesson for the great challenges of today, so poorly attended to. These two men had
much in common, and might therefore have become close comrades. But because they looked at
the world from different perspectives, they came eventually into conflict. That is a rough
sketch of the architecture of my lecture. But this being formally a Tillich Lecture, let
me reassure you right away that my credentials for giving it do not rest on any claim that
I am an intimate student of Tillich’s theology, or that I have come to clarify some
puzzles in his writings. Others here, including Mr. William Crout, who has kindly shared
with me his recollections and sources, are much more familiar with Tillich’s work,
with his vast Archive in the Theological Library at our Divinity School, with his official
Collected Works in fourteen volumes, in addition to his many other books, and the more
than 1200 entries in the catalog of the Harvard Libraries that refer to works by or about
him.

3controversies, and also his liveliness at age 69. As his student and assistant, Paul
Lee, said later, Paul Tillich was, "as a scholar, a one-man theological
symphony," yet also, unlike some other academics, "passionate, full of desire,
vibrant with vitality." Indeed, one was immediately drawn to him. [2.5 min. videotape
of Tillich interview] Tillich had just come to Harvard from the Union Theological Seminary
in New York, where he had found refuge after being forced to leave Germany, dismissed
there from his professorship at the University of Frankfurt in 1933, in the first weeks of
the Nazi regime. He had been one of its outspoken opponents. In 1951 he had published the
first volume of his master work, Systematic Theology, and was working on the other two volumes, issued in 1958 and 1963. He had just
given lectures at the University of Virginia on "Biblical Religion and the Search for
Ultimate Reality". There he had said: "The God who is a Being is transcended by
the God who is Being itself, the ground and abyss of every Being. And the God who is a
person is transcended by the God who is the Person-Itself, the ground and abyss of every
person. …. Against Pascal I say: ‘The God of Abraham, Isaac and Jacob and the
God of the philosophers is the same God. He is a person, and the negation of himself as a
person." I have selected these passages for two reasons: to prepare us for the
conflict over the concept of the Personal God, which will become important later in this
account, and to alert you to the dialectical style in Tillich’s thinking, a style
which James Luther Adams, arguably his most eminent commentator, called "a philosophy
of paradox". To return to the dinner: When Tillich’s presentation began, he
turned to us with a question: Would we like him to outline two of his central ideas, which
were, as he put it, …..

"God is the infinite ground of Being," and "Mankind’s highest duty
is to focus on Ultimate Concerns"? There was a long, awkward silence. What might have
troubled my colleagues in their silence? Surely, no problemwith the word "God."
It was the first thing you expected to hear from a theologian. And in any case, even the
scientists there knew that some of their kind had been practically on first-name terms
with God. A famous example was the great experimental physicist, I. I. Rabi. He wrote
once, "[Physics] filled me with awe, put me in touch with the sense of original
causes, brought me closer to God….Whenever one of my students came to me with a
scientific project, I asked only one question: ‘Will it bring you nearer to
God’?". For his part, Einstein had said memorably: "What really interests
me is whether God had any choice in the creation of the world." And to this day, Stephen Hawking, among others, is
implicating the deity in his research findings . So, if the assembly was not puzzling over
the word "God," perhaps it might be pondering over the word "Being,"
in the phrase "God is the infinite ground of Being." That word in English is
such a pale reflection of the complex and historically fought-over concept, Sein, or
Seiendes, concepts Tillich had been using since his earliest days in Germany, not only
because there he had to study books like Hegel’s Die Lehre von Sein , and also for a
time had been a faculty colleague of Martin
Heidegger (in Marburg). Or perhaps Tillich’s audience was
trying to adjust mentally to the phrase "ultimate concerns," one of his favorite
terms ["ultimate" in his German was "das Unendliche, das Unbedingte"].
But each of us there should have thought immediately of victors and victims in pursuit of
ultimate concerns, their grand challenges. Among

6surrounded mostly by theologians; so I had no opportunity to learn from them what I
can learn from you. I would love to do that now." He had us in the palm of his hand.
Of course, a few of us there, including myself, gladly agreed to set up an informal
workshop, meeting with Tillich several times, and learning from him and one another. To
preview one thing we quickly learned from Tillich: He told us that he thought of the
meaning of ultimates and especially of infinity by means of visual metaphors.
Visualization and symbolism in art were important to him. He routinely included pictures
in his lectures, in order to show, as he put it once, "the possibility of breaking
the surface of reality in order to dig into its depth….and you cannot understand
theology without understanding symbols." Such a symbolic use of an image, he said,
would help us to understand how he perceived the "symbol" of infinity. Thus
Tillich said that sitting at the edge of an ocean and gazing out, the view was for him a
symbol of the infinite, hinting at an infinite depth before him, but also bordering on the
finite, as he was positioned on the beach, the boundary between the two. Here I remembered
Friedrich Schiller’s famous couplet, "Only
fullness leads to clarity, and truth lies in the abyss" [Nur die Fuelle fuehrt
zurKlarheit, und im Abgrund wohnt die Wahrheit]. Let us look now
more closely at some of Tillich’s key ideas and how they originated, and then compare
these with Einstein’s own main motivating concept. For this purpose it would of
course be interesting to know whether and when our two protagonists actually met. They
might very well have done so early, in Berlin. Einstein was in Berlin from 1914 until
1932. Tillich came there in 1919, a time of great chaos, and

9 the medieval town walls. His father was an authoritarian Lutheran minister and his
mother, as he wrote, was also morally rigid. Young Tillich found refuge in what he called
a "romantic", "aesthetic meditative attitude toward nature",
reinforced by the "deeply moving" nature mysticism in beloved German
poetry—Goethe, Hoelderlin, Novalis, Nietzsche, George, Rilke. Such readings led him
to a vision, as he put it, of the presence of the infinite in the finite, which he
regarded as also theologically affirmed. Eventually it came to confrontations with his
stern father, the "angry" supporter of "the conservative point of
view". Tillich rebelled against it both philosophically and politically, eventually
becoming a prominent supporter of Germany’s Religious Socialism. Here Tillich
added," The two strong motives I received", were "the romantic and the
revolutionary. The balance of these two motivations has remained the basic problem of my
thought and of my life ever since". In his
Gymnasium years, he adored ancient Greek and Greek culture, especially the pre-Socratic
philosophers, Heraclitus and Parmenides, of whom he wrote later (The Future of Religion,
1966) nothing in all of philosophy written since then has surpassed them. At that point in his autobiography, Tillich suddenly writes: "The way to
synthesis was my own way. It followed the classical German philosophers from Kant to
Hegel, and remained a driving force all my theological work". On his own, starting
when still in high school, young Tillich studied works of Kant, Fichte, Schleiermacher,
Hegel and Schelling. When he came to do his doctoral dissertation, it was on
Schelling’s philosophy of religion. Later he turned to the period when Schelling
broke with Hegel’s "system of reconciliation" and pointed toward
existentialism.

10 That turn, Tillich told elsewhere, was furthered by two factors. One, surprisingly,
was that, when still in his teens, Tillich came upon a book he regarded as the most
important of all: Shakespeare’s Hamlet, in August
Wilhelm von Schlegel’s translation.He learned the whole play by heart, and was
completely taken with its central existential question of the meaning of life, which
Hamlet summarized of course in his phrase, "To Be or Not To Be", or rather, in
Schlegel’s words, "Sein oder Nichtsein, das ist hier die Frage". It may not
be an accident that in the first volume of Tillich’s Systematic Theology there is a
chapter headed "Sein und Nichtsein". The second factor was an event that,
Tillich said in an interview, was for him a crucial life-changing experience. During the
whole First World War, Tillich was a chaplain with the troops, often at the front. One
night, in a terrible battle, he saw all around him his friends and comrades die miserably
of their wounds. He said about this. "My eyes were opened forever to the negative
side of life. My philosophical thinking went from idealism to existentialism…. [I now
saw] the human predicament, with its despair, guilt, anxiety, emptiness, meaninglessness,
death, as seen by modern novelists and artists." " My world and idealist
philosophy collapsed." His reading now included Marx and Freud. And he realized that
his work was drawing on "competitive motives ofthought", on both his earlier and
his later sensibilities, resulting in "a certain inconsistency and indefiniteness of
terminology." During his years in Berlin, Tillich published in 1923, at age 37, his
first large book, Das System der Wissenschaften ,
nach Gegenstaenden und Methoden ( The System of the Sciences according to Objects and
Methods), with the accent strongly on the "Das". Not only
was it a step to his later, second system, that of theology. We can see….

11 here already Tillich in the firm grip of a synthesis on behalf of a great mission.
Intending to encompass all knowledge under three headings—Denken, Sein and Geist –
Tillich deals here essentially with the systematization of all cognitive disciplines, as
he had been doing in his lectures. Therefore the book deals with logic, mathematics,
phenomenology, the empirical sciences from physics to geology and the life sciences, on to
psychology, sociology, history, art, law, metaphysics, ethics, philosophy, and of course
theology. Amain purpose of the book was to find the place for theology, and to show that
every field can have a theological component. In his introduction to the book, Tillich
explained that he saw it as his duty to provide "an overview of the whole of
knowledge", and also to put it in the service of necessary social change. No wonder
some of his colleagues lashed out at him.As we are about to turn now to Einstein’s
analogous passions, we come upon a happy surprise. I said earlier that we have no sure
evidence that Einstein and Tillich met personally in Berlin. But there happily exists at
least one documentable joint appearance of those two at another place, a meeting that had
important and unexpected consequences for each of them. There exists a photograph in the
Tillich Archive at our Divinity School library. It shows both of these men at a pleasant
gathering of about two dozen persons.Among them is Tillich at age 41, and Einstein who
just had entered his 50^th year. [PHOTO] The
place is Davos in Switzerland, and the time is Sunday, the 18thof March 1928. This is a group of well recognized intellectuals from many fields of study.
They had come from Germany, France, Austria and Switzerland, during the spring break at
their…

12 universities. It is still a year before the start of the Great Depression, a time
when one could still hope for a civilized century. That town was still small, not yet
today’s fashionable sports and congress center for the Masters of the Universe. This
group had gone there on a humanitarian mission. Davos was then, as it had been for decades, the site for many sanatoria, for patients
suffering from pulmonary tuberculosis. Those patients lingered there in the belief that
they would be cured by the good mountain air and the sunlight, at this altitude of 5000
feet. The place had already gained extra attention since the publication, four years
earlier, by the book, The Magic Mountain, by Thomas Mann (later to become another refugee of the class of 1933). In
short, we are looking at the Zauberberg, to which came Hans Kastorp and his doomed cousin, Joachim
Zimmens, two typical young students whose general isolation in the sanatoria, far from the
outside world of action and ideas, only worsened their condition. That general fate of the
patients was precisely why this group of prominent academics had come there in 1928. They
were starting a month-long Alpine University. Their unselfish mission was to give lectures
and hold discussions, hoping thereby to enlighten and cheer up those young people from the
sanatoria. The lectures, in German and French, were on science, philosophy, literature,
jurisprudence, and sociology: six or seven of these every day, six days a week, from
forty-five lecturers when all had arrived, including people like Lucien Levy-Bruhl and Jean Piaget. The audience
consisted of some 360 students and 400 others from the environs, all crowding into the
Grand Hotel Curhaus.

13 Einstein gave the inaugural lecture, on "The Fundamental Concepts of Physics in
its Development," and he remained fully engaged during the time of his stay–perhaps
too much so. He attended other professors’ lectures assiduously, met with individuals
and small groups, even played his violin at a chamber concert, to help raise funds for
this new university. Tillich gave two lectures, one on "Religion and Culture,"
and the other on "The Religious Knowledge". Little did Tillich and Einstein know
that this meeting would, for each of them, be a turning point in his life. Tillich had
come from his professorship, now at the University of Dresden. He had by now published
about a dozen books and many articles, ranging from Schelling and Schleiermacher to
religious socialism. This last was to be understood as socialism studied from a religious
point of view, and intended to lead to activities improving the social situation, unlike
other prominent Protestants such as Karl Barth, who, Tillich complained, "virtually
ignored the social situation." Einstein, on his side, was now at the height of his
fame, chiefly thanks to his general relativity theory; but, like Tillich, he too was
always ready to throw himself into the social problems of the day, often to the dismay and
disapproval of his nearer colleagues. At Davos, Tillich was in high demand, surrounded by students and colleagues. His former
teacher, Fritz Medicus, saw and heard him, and wrote that Tillich was clearly "the
coming man in philosophy. One of Tillich’s talks at Davos was scheduled to follow upon one by a speaker
who had given the rather pessimistic prediction that civilization was declining on an
exhausted soil in Europe. Upon that, Tillich rose and objected. The religious person, he
held, is used to finding himself in a crisis. That may even help him…..

That may even help him to avoid false certainties, and lead him to turn to the
necessary and reliable certainty in God. In the audience were two psychologists from the
University of Frankfurt. They decided right then and there to propose that Tillich be
called to the University of Frankfurt—and that in fact happened the next year, to
Tillich’s joy. Frankfurt was then a great place for a theologian, since it was the
home also for the outstanding Jewish theologians,
Martin Buber, Franz Rosenzweig, and their brilliant student, Nahum Glatzer. In terms of intellectual production and influence, Tillich’s years at
Frankfurt were to be arguably his best so far. As Adams remarked about Tillich’s
works during those days, "We see here the fundamental impulses that pervaded
Tillich’s whole career. He wished to make the prophetic and sacramental, the
theological and the philosophical relations relevant to the present historical situation,
and he did this by means of a constant dialogue with the creative and critical figures of
past and present." In short, when Tillich left Davos and went on to his post in Frankfurt, he could consider that his kindness to the
Davos students well rewarded.
As to Einstein, his vigorous participation in Davos had also long-term consequences, but of a very different kind. His biographer
and son-in-law Rudolf Kaiser wrote later, that Einstein had been persuaded to come to Davos because of his concern for those sick
students, lying there without intellectual challenges. But Einstein himself did not feel
physically well in the beginning of that year. As Rudolf Kaiser revealed, "In Davos started [Einstein’s] severe
heart disease, which kept him chained to his bed for a long time." It was a debility
that he had to suffer from later on.

15 I have said nothing yet about the inaugural lecture Einstein
gave at Davos. The body of the lecture was essentially a deep bow to
Schopenhauer’s determinism, which Einstein had accepted from first to last. Einstein in that year was preoccupied by the current debate about the role of
causality, a debate caused by the rise of the so-called Copenhagen interpretation of
quantum mechanics, of Bohr, Heisenberg, Born, etc. The remarkable success of their new
physics was based on their thematic belief that natural phenomena at the atomic scale were
not classically causal but indeterminate, probabilistic. Einstein then, and for the rest
of his life, was certain that he could rely on what he called in that Davos lecture "my scientific
instinct," namely, that the new quantum mechanics was a temporary phase, that
ultimately, one would interpret "events as necessary and fully under the law of
causality," a program which he noted to have been "divined by the great
materialists of Greek antiquity." Indeed, his own theory ofrelativity was, he said,
"nothing more than a further consequential development of the [older] field
theory," based on causality. So far, so good. Einstein too had been a builder of a
system, now to be defended against the swarm of probabilists. And if Einstein had not said
anything else in that lecture, which Tillich surely attended, all might have been well
between them. But in his lecture, Einstein had another paragraph. In fact, he had started
the whole talk with one of his persistent opinions, namely that the scientific triumphs
throughout history, based on strict causality, showed the uselessness of seeking "to
refer all that happens to the exercise of will on the part of invisible spirits."
Moreover, he characterized that belief as worthy only of "primitive man."

We can only speculate what Tillich thought about this, perhaps an early version of a
paragraph in his later book, Dynamics of Faith: "Scientific truth and the truth of faith do not belong to the same
dimension of meaning. Science has no right and no power to interfere with faith, and faith
has no power to interfere with science. One dimension ofmeaning is not able to interfere
with another dimension". Let us now take a few minutes to look more closely at
Einstein, in preparation for the coming conflict with Tillich. Einstein’s urgent
mental and metaphysical compunction, his own ultimate concern, were hinted at in an
article of 1916, where Einstein had written: "What goal will and can be reached by
the science to which I am dedicating myself?" And he answered: "To dedicate
oneself to what is essential, as against what is based only on the accident of
development." Under this self-demand, he had turned to extending his original theory
of relativity of 1905 into his general theory, or rather, as he significantly called it at
first in print, to his "generalized" theory of relativity. I have written about
the great significance to Einstein of this term, "generalized." Here I need only
summarize by noting that in his publications, and especially in his letters from 1899 on,
Einstein spoke again and again of what he confessed to be the strongest moving force in
his intellectual life. "I am driven by my need
to generalize," he wrote to his friend W. De Sitter. His
relativity theory of 1905, stunning though it was, and is to this day, was unsatisfactory
for Einstein himself, because it did not apply to accelerated frameworks and gravitation.
Therefore, working himself for many years to near physical breakdown in order to
generalize the special relativity theory, he produced by 1916 what has ever since been
widely acknowledged to be an almost superhuman …

accomplishment, the General Theory. Now Einstein was able to apply the theory to the
whole cosmos. One section of his popular book of 1917 on the theory had the heading "Consideration about the World as a Whole." Nothing less. In an article of the same year, applying his theory to cosmology,
he found that the theory allowed him to calculate the density and size of the universe
itself. Upon the success of the experimental test ofthe theory in 1919, one could almost
feel that with his theory Einstein could answer the key question, "what holds the
world together in its innermost," the challenge that had obsessed Goethe’s
Faust. Compared to what Einstein had done, most problems of other scientists, their other
concerns, seemed to sink into relative insignificance. Einstein was confident of his
success even before the 1919 test of his theory. He had declared, in a widely read speech
in 1918 that the supreme task, the highest duty, of physicists is to seek the most
universal elementary laws from which, by pure deduction, the whole world picture can be
achieved. And he confessed there that "the longing to behold this pre-established
harmony, requiring inexhaustible patience and perseverance, can only come from a
‘state of feeling’ akin to that of a religious worshipper or one who is in
love." On this, Tillich would have agreed. On the final page of his book of 1923 he
had called the pursuit of the Wissenschaften to be a spiritual act. He repeatedly used the
trio of Eros, passion, and scientific sobriety to describe the necessary mindset for
reachingtoward the ultimate. Indeed, to Tillich, the pursuit of such exalted aims was what
he called the "religious element in the whole intellectual enterprise," and he
defined religion as "the state of being grasped by an ultimate concern."
Einstein, for his part, analogously

adopted it eventually only after most scientists, starting with Max Planck in 1906, had
freely used that term to refer to Einstein’s work. Einstein himself had thought his
theory from the beginning to be not a revolutionary act, but merely, as he put it to his
friend Habicht in 1905, a point of view "making use of a modification of the theory
of space and time." He saw his work as an act of simplification, of generalization,
hence an aesthetically more pleasing way to think about physics. He called it
significantly his "Maxwellian Program." And he complained in letters to friends that a correct term for his work would
at best have been Invariantentheorie, a theory not
of relativity at all, but of the opposite, of invariance, of constancy. After all, the whole point of his theory was that Einstein had found a way to
rewrite the known laws of physics so as to make them for the first time independent of the
relative points of vantage of different observers. Moreover, a key postulate in it was
Einstein’s declaration of the absoluteness of the speed of light, regardless of the
relative motion of the observer. So it would have been not unreasonable for physicists to
call Einstein’s work the theory of absolutes. Of course, as he later said in
resignation, it was now too late to change the terminology. The semantic time bomb
exploded in the 1920s, with collateral damage to this day. The very existence of the
theory of relativity has been often and wrongly held to illustrate, and in extreme cases
even to be responsible for, the perceived relativization of ethics and other common
values. Einstein’s long struggle with religion has been amply documented, starting
with his remark on the very first page of his Autobiography that as a child, although
"the son of entirely irreligious [Jewish] parents," he came "to a deep
religiosity up to the age of….

twelve." One may surmise that we have here a rebellion against his parental
beliefs, ironically analogous to Tillich’s case. While Einstein soon turned his back
on any organized religion, the seeds of young religiosity in Einstein flourished greatly
in his later years, partly under the influence of Spinoza’s Ethics, one of his favorite books. His religious
views are thought even to have penetrated into choices he made in his physics. Up to about
1930, this part of his concerns kept a low profile. Then, between 1930 and 1948, he
published several widely discussed articles on religion and science, with the first of
these called simply "Religion and Science", setting forth his idea that what he
called "the cosmic religious feeling" is the most advanced and only acceptable
stage of religion. Elaborating in these essays onhis earlier remarks, such as his brief
ones at Davos, Einstein
explained that the concept of a Personal God was an anthropomorphic remnant of primitive
times, of a religion of fear. It had to be abandoned in favor of a Spinozistic feeling of
awe and "sense of ‘wonder’" at the rationality and beauty of the
universe. Moreover, as one who believed in the "universal operation of the law of
causation", Einstein could not entertain "for a moment", as he said,
"the idea of a being who interferes in the course of events"—such as
causing prayers to be answered, or miracles to occur. And Einstein concluded that
"serious scientific workers are the only profoundly religious people." More
ideas along this line were to come from his pen shortly. A key event in our story is
Einstein’s essay entitled "Science and Religion." It appeared as part of a
remarkable symposium on the topic "Science, Philosophy and Religion in their Relation
to the Democratic Way of Life". That symposium, held in New York, was convoked by a
stellar group of intellectuals from a wide range of fields. Both Einstein and Tillich
signed

the call for the meeting. The main hope of this exercise was to arrive at some sort of
unity among all their different fields of knowledge, in the service of preventing
civilization from being undermined by unnecessary disputes, just when totalitarianism was
sweeping over Europe. That Symposium volume is a fascinating document. This is where
Tillich re-enters in our story. For when Tillich read Einstein’s essay in that
volume, he felt deeply troubled by it. Einstein had reemphasized his concept ofcosmic
religion. As he had put it there, a main source of the conflicts between the spheres of
religion and of science lies in this concept of a personal God. Because Einstein believed
that the law of causality applied to all physical events, it was inconceivable to him that
a "Divine Will exists as an independent cause of natural events". He called on
all "teachers of religion" to "have the stature to give up the outdated
doctrine of a Personal God, that is, give up that source of fear and hope which in the
past placed such vast powers in the hands of priests." He added that it was only the
perception of the "grandeur of reason incarnate in existence" which
"appears to bereligious in the highest sense of the word." In this way, science
"purifies the religious impulse of the dross of its anthropomorphism," and
"contributes to a religious spiritualization of our understanding of life."
Strong words. While Tillich was of course by no means of the conservative camp, he thought
that some response was called for. Within two months of the publication of Einstein’s
essay, Tillich issued his reply, entitled "Science and Theology: A Discussion with
Einstein" [not "discussion" but Auseinandersetzung, to put apart, to separate, to dissolve a partnership, in the German of
G.W.v.XII,p.300]. Precisely because that negative critique of the notion of a Personal God
had been propagated by a man whom Tillich

regarded as the great transformer of our physical worldview, and to whom he had often
referred in admiring terms, these remarks could not be left unchallenged. In his published
reply, Tillich said rather sharply that Einstein had not understood the meaning of his own
words. For when Einstein had written about that awe at the "grandeur of reason
incarnate in existence," Einstein had failed to notice that modern theology calls
this "experience of the numinous" simply "the manifestation of the ground
and abyss of being and meaning." And in attacking the conception of the Personal God,
Einstein was only railing against an old, out-of-date mixture of mythological and rational
elements, even an unclean one. "No criticism of this distorted idea of God can be
sharp enough." Einstein had not noticed, Tillich added, that "God" is a
symbol, that the predicate "personal" can be said of the Divine "only
symbolically or by analogy, or if affirmed and negated at the same time." And that
symbol of God was needed for man’s existence: "For as the philosopher Schelling
says: ‘Only a person can heal a person.’ This is the reason that the symbol of the Personal God is indispensable for
living religion. It is a symbol, not an object". And there was more. Tillich’s
suspicion now focused also on the concept of relativity itself. Traces of that suspicion
in Tillich’s mind can be found years before the Davos meeting, for example in Tillich’s essay of 1924, entitled "The Tension
of the Absolute versus the Relative in the Philosophy of History." There, Tillich
condemned relativism in history, along with Marxism and positivism. And four years after Davos (in "The Religious
Situation," 1932), Tillich had referred directly to the "modern theory of
relativity," which eliminates "every absolute point of reference." To be
sure, he said, the theory of relativity "has revealed more clearly than was
previously apparent the infinity….

other intellectuals. I searched there for any letter exchange between Tillich and
Einstein. But there are only three mailings, all from Tillich, and none addressed to
philosophical issues. One is an appeal to join in helping yet another refugee from Nazism,
another is a request to join an organization of Self-help for German Émigrés, which
Tillich headed for 15 years, and the third is Tillich’s analysis in 1942 of the war
aims of the Allies. The content of all those mailings were fully in accord with
Einstein’s well-known views. But we do not know whether Einstein replied to any of
them. On that, the Archive is silent. * * * It had started so auspiciously, with those
great minds assembled on that meadow on the Zauberberg
in 1928, having come there with a common sense of service. Our two
protagonists had so much in common. They had been exposed to the same holistic cultural
inheritance, as well as the same dangers. Each worked seriously in his own way on an
integration, unification and reconciliation of different areas of culture, including
science and religion. Each had produced a commanding system in his field. Each had
carefully and with much pain developed his system over a long period, making this
self-appointed task the very center of his life. And when we look at their main legacies,
there stands out forcefully one common theme: The quest for the unification of
apparentirreconcilables. For Einstein it was, as we have seen, to try to bring together
the major fields of physics, and from there to construct for himself even a religion that
was fused with his cosmological thoughts. Tillich, author of several synthesis-seeking
works, wrote in the Foreword of the first edition of his 1923 book, Das System der Wissenschaften, as
follows: "All Wissenschaften function in the service of one truth, and Wissenschaft
collapses if it loses….

the sense of connection of the whole." One of his courses at Harvard had the
breathtaking title "Religion, Art, and Science." In his search for a synthesis,
Tillich was trying to develop a theological and religious position as ambitious and
advanced as what Einstein was attempting in his own field. Tillich called his work once
"the experiment to which my whole life is dedicated, the reunion of what eternally
belongs together but what has been separated in history". So we may be tempted,
finally, to think that these two kindred spirits might well have developed a mutual
Elective Affinity, if only they had been brought together for heart-to-heart discussions.
One can imagine what they could have said to each other, being both culture-carriers of
the old sort, deeply admiring many of the same classic philosophers, above all Spinoza,
and also having inherited much of 19th-century sensibilities, including sensitivity to
what has been called the vocabulary of the scientific sublime, "reverence and awe,
reason and progress." That a Personal God is a symbol instead of a mere
anthropomorphic fantasy might have been acceptable to Einstein. He might not have objected
to Tillich’s definition, "The ultimate concern is
unconditional…total…." In turn, it would have appealed to Tillich that Einstein’s relativity was as much a search for Absolutes as was Tillich’s Systematic Theology; and conversely, Einstein would of
course have agreed to oppose the false uses of the word "relativity."But we must
avoid imagining such a "Happy Ending". Protagonists at such exalted levels tend
to persist in their life’s program with a certain stubbornness. They tend to cling
fiercely to their thematic presuppositions. In fact, that is part of their…

strength. Einstein and Niels Bohr, too, while deeply respecting each other, never
deviated, during their long debates, from their divergent views. The differences we saw
between Einstein and Tillich are for us in fact an advantage: They have sharpened our
understanding of their respective intellectual landscapes. And the similarities in their
ambitious programs gave us two exemplars of true Questers, who devoted their lives to
complementary searches, each animated by his own ultimate
concern.