Eudemo di Rodi
Eudemo di Erasmo
Eudemo di Rodi - Filosofo greco (sec. IV aC). Allievo di Aristotele, insegnò probabilmente a Rodi. Scrisse una storia dell'aritmetica e della geometria e storie dell'astronomia e della teologia. A lui fu erroneamente attribuita l'Etica Eudemea, trasmessa fra gli scritti del maestro.
Le enciclopedie italiane non sono molto eudemoniche - non nel senso di felicità come scopo della vita, ma come informatrici circa Eudemo di Rodi - per cui più esaurienti notizie possono essere desunte dagli elaborati che seguono. Cominceremo con l'elencare i vari Eudemo della storia.
Possiamo essere quasi certi che l'Eudemo di Erasmo non corrisponde a quello citato alcune volte da Eliano in La natura degli animali e corrispondente al secondo Eudemo elencato da William Smith. Ciò per due motivi. Innanzitutto Francesco Maspero, che ha tradotto quest'opera di Eliano (BUR, 1998), nelle note a pie' pagina scrive esplicitamente trattarsi di un autore sconosciuto; in secondo luogo - il che è più importante - perché tra le varie citazioni di Eudemo da parte di Eliano non compare il gallo. Per non ripeterci, le citazioni di questo misconosciuto Eudemo in Eliano corrispondono ai capitoli e ai paragrafi riferiti da William Smith.
Dictionary of Greek and Roman Biography and Mythology
William Smith, Boston, 1867
Eudemus of Rhodes (Εὔδημος)
was an ancient Greek philosopher, who lived from ca. 370 until ca. 300 BC. He
was the first historian of science. He was one of Aristotle's most
important pupils, editing his teacher's work and making it more easily
Eudemus was born on the
isle of Rhodos, but spent a large part of his life in Athens, where he
studied philosophy at Aristotle's Peripatetic School. Eudemus's
collaboration with Aristotle was long-lasting and close, and he was
generally considered to be one of Aristotle's most brilliant pupils:
he and Theophrastus* of Lesbos were regularly called not Aristotle's
"disciples", but his "companions".
It seems that Theophrastus
was the greater genius of the two, continuing Aristotle's studies in a
wide range of areas. Although Eudemus too conducted original research,
his forte lay in systematizing Aristotle's philosophical legacy, and
in a clever didactical presentation of his teacher's ideas. Later
authors who wrote commentaries on Aristotle often could made good use
of Eudemus's preliminary work. It is for this reason that, though
Eudemus's writings themselves are not extant, we know many citations
and testimonia regarding his work, and are thus able to build up a
picture of him and his work.
Aristotle, shortly before
his death in 322, designated Theophrastus to be his successor as head
of the Peripatetic School. Eudemus then returned to Rhodos, where he
founded his own philosophical school, continued his own philosophical
research, and went on editing Aristotle's work.
Eudemus was the first
historian of science. At the insistence of Aristotle, he wrote
histories of Greek mathematics and astronomy. Though only fragments of
these have survived, included in the works of later authors, yet their
value is immense. It is only because later authors used Eudemus's
writings that we still are informed about the early history and
development of Greek science. In his historical writings Eudemus
showed how the purely practically oriented knowledge and skills that
earlier peoples such as the Egyptians and the Babylonians had known,
were by the Greeks given a theoretical basis, and built into a
coherent and comprehensive philosophical building.
As regards his History
of Arithmetics we
only have the tiniest bit of information: there is only one
testimonium, saying that Eudemus mentions the discovery by the
Pythagoreans that it is possible to connect musical intervals with
Eudemus's History of
Geometry is mentioned by many more writers, including Proclus,
Simplicius, and Pappus. From them we know that the book treated the
work by, among others, Thales of Miletus, the Pythagoreans, Oenopides
of Chios, and Hippocrates of Chios. Among the topics Eudemus discussed
were the discovery of geometrical theorems and constructions (systematized
in Eudemus's days by Euclid in his Elements), and the classical
problems of Greek geometry, such as the quadrature of the circle and
the duplication of the cube.
We know quite a lot too
about Eudemus's History of Astronomy, from sources such as
Theon of Smyrna, Simplicius, Diogenes Laërtius, Clement of Alexandria,
and others. Building upon those data we can reconstruct with some
accuracy the astronomical discoveries that were made in Greece between
600 and 350 BC, as well as the theories that were developed in that
period regarding the earth, solar and lunar eclipses, the movements of
the heavenly bodies, etcetera. Philosophers and astronomers treated by
Eudemus include Thales, Anaximander, Anaximenes, Oenopides, Eudoxus,
Two other historical works
are attributed to Eudemus, but here his authorship is not certain.
First, he is said to have written a History of Theology, that
discussed the Babylonian, Egyptian, and Greek ideas regarding the
origins of the universe. Secondly, he is said to have been the author
of a History of Lindos (Lindos is a port on Rhodos).
Eudemus is also ascribed a book with miraculous
stories about animals and their humanlike properties
(exemplary braveness, ethical sensitivity, and the like). However, as
the character of this work does not at all fit in with the serious
scientific approach that is apparent from Eudemus's other works, it is
generally held that Eudemus of Rhodos cannot have been the author of
this book (it may have been another Eudemus—Eudemus was a fairly
common name in ancient Greece).
Eudemus, Theophrastus, and
other pupils of Aristotle took care that the intellectual heritage of
their master after his death would remain accessible in a reliable
form, by recording it in a long series of publications. These were
based on Aristotle's writings, their own lecture notes, personal
Thus one of Aristotle's
writings is still called the Eudemian Ethics, probably because
it was Eudemus who edited (though very lightly) this text. More
important, Eudemus wrote a number of influential books that clarified
was a compact, and more didactical version of Aristotle's
Eudemus wrote two or three
books dealing with logics (Analytics and Categories (possibly
the same book), and On discourse), which probably expounded
Finally, a geometrical
work, On the angle.
A comparison between the
Eudemus fragments and their corresponding parts in the works of
Aristotle shows that Eudemus was a gifted teacher: he systematizes
subject matter, leaves out digressions that distract from the main
theme, adds specific examples to illustrate abstract statements,
formulates in catching phrases, and occasionally inserts a joke to
keep the reader attentive.
Ivor Bulmer-Thomas, 'Eudemus
of Rhodes', in: Dictionary of Scientific Biography, Charles
Coulston Gillispie, ed. (18 Volumes, New York 1970-1990) Volume IV
(1971) pp. 460-465.
F[ritz] Wehrli, 'Eudemos
von Rhodos', in: Paulys Realencyclopädie der Classischen
Altertumswissenschaft, G. Wissowa, ed. (51 Volumes; 1894-1980)
Vol. Suppl. XI (1968) col. 652-658.
by: J J O'Connor and E F Robertson
should certainly credit Eudemus of Rhodes for his achievements in this
archive since Eudemus seems to have been the first major historian of
mathematics. Simplicius informs us that a biography of Eudemus was
written by Damas, who is unknown but for this reference, but sadly no
trace of this biography has been found. As exciting aspect of the
history of mathematics is that the discovery of this text (and other
lost texts) in the future, although highly unlikely, always remains a
was born on Rhodes and we know that he had a brother called Boethus.
Of his parents and early life we know nothing, but we do know that he
studied with Aristotle. Aristotle spent time in Athens, Assos and
other places and it would certainly be good to understand when Eudemus
studied with him. Unfortunately there is no record either of time or
of place which would let us answer these questions with any degree of
certainty. W Jaeger, however, in his discussion of Aristotle  (see
also ) has argued strongly that Eudemus studied with Aristotle
during his period in Assos.
had two followers, Eudemus and Theophrastus of Lesbos, who were known
as his "companions". We should make it clear, however, that
there was another philosopher called Eudemus associated with Aristotle,
namely Eudemus of Cyprus and it was this other Eudemus after whom
Aristotle named his famous text Eudemus. When Aristotle realised that
he had only a short time left to live he chose his successor between
his two companions, Eudemus and Theophrastus. He chose Theophrastus
and it appears that Eudemus, although not unhappy with the decision,
left Athens and set up his own school, probably back on his native
say that Eudemus was not an original mathematician may be fair but
just a little harsh, for we do know through Proclus that he wrote an
original mathematical work called On the Angle. This work is lost so
we are unable to judge its importance but it does seem likely to have
been considerably less important than his works on the history of
know of three works on the history of mathematics by Eudemus, namely History
of Arithmetic (two or more books), History of Geometry (two
or more books), and History of Astronomy (two or more books).
History of Arithmetic is known to us from only one reference to
it in the writing of Porphyry. This reference tell us that the first
book dealt with the Pythagorean idea of number and its interrelations
History of Geometry is the most important of the three
mathematical histories of Eudemus. Although the work has not survived,
it was available to many later writers who made heavy use of it. We
are fortunate therefore that much of the knowledge that Eudemus had of
the history of Greek mathematics before Euclid (it had to be before
Euclid given the dates when Eudemus was writing) has reached us
despite the fact that he book has not. In many of the articles in this
archive we have quoted from accounts based on Eudemus. To illustrate
with one example, the work of Hippocrates on the quadrature of lunes
is only known to us through Eudemus's History of Geometry.
is unclear exactly when the History of Geometry was lost. Paul Tannery
(see for example ) believed that it was lost before the time of
Pappus while others such as J L Heiberg have argued that Pappus and
Eutocius both wrote with an open copy of Eudemus's History of Geometry
in front of them.
History of Astronomy again was heavily used by later writers
and in exactly the same way as his geometry text, much information has
survived in the works of others despite the loss of the original text.
In particular Thales' eclipse prediction was described in Eudemus's
work and we believe that Eudoxus's system of concentric spheres was
first described there and later transmitted to us through the writing
of Simplicius in the second century AD. Other topics in this book
the cycle of the great year after which all the heavenly bodies are
found in the same relative positions; the realisation by Anaximander
that the earth is a heavenly body moving about the middle of the
universe; the discovery by Anaximenes that the moon reflects the light
of the sun and the explanation of lunar eclipses; and the inequality
of the times between the solstices and the equinoxes.
have described above the important contributions of Eudemus to
mathematics. However he is even better known for his contribution to
saving the work of Aristotle for posterity. But for Eudemus we might
not have had access to the works of Aristotle for he used his own
lecture notes, Aristotle's lecture notes and recollections from memory
to produce volumes of Aristotle's work fit for publication.
further work is definitely due to Eudemus, namely a work on Physics
which was a treatise in four books following the work by Aristotle of
the same title fairly closely. Simplicius had a copy of this work
which he found very helpful in understanding Aristotle's Physics and
perhaps this was precisely the role the Eudemus intended for the work.
Another work by Eudemus was on Logic, in fact he may well have
written two logic books and he also wrote On Discourse.
works by Eudemus are harder to identify with Eudemus of Rhodes and may
have been written by others with the same name. Certainly there are
many references to a work on
animals written by a certain Eudemus
and one of the references certainly does refer to Eudemus of Rhodes.
Since the work seems to have been a collection of fables about animals
the subject matter seems too far removed from the serious, scientific
and scholarly works which he certainly wrote. Perhaps more likely is a
work on the poet Lindos. Since Lindos had connections with Rhodes the
link makes this a more likely possibility.
there is a reference which seems to imply that Eudemus wrote a history
of theology and again this seems highly probable. Many authors refer
to Eudemus as the 'pious Eudemus' due to his belief in the 'contemplation
of God'. This however may be due to editing by a later Christian who
would have seen that clearly Eudemus meant 'contemplation of God'
rather than what is much more likely what he wrote 'contemplation of
Mind' and "corrected" the text accordingly!