*(JHA,xi 1980, p. 133-135)*

*The Crime of Claudius
Ptolemy. *Robert R. Newton (The Johns Hopkins University Press, Baltimore
and London, 1977). Pp. xiv + 411. £15-75.

Whatever various generations
of astronomers and of historians of astronomy have thought and shall come
to think of Ptolemy, his *Almagest *(or *Syntaxis, *as Newton
prefers to name it) is bound to remain a grand focus in the history of
astronomy. Here a thousand years' work of Babylonian and Greek astronomers
evolved into a comprehensive account, in geometrical language, of all the
motions in the sky. Here the stage was set for another fifteen centuries
of efforts, on the part of Indian, Arabic, and Latin astronomers, to maintain
control with these motions. So any major change of view concerning the
development of any part of the history of astronomy from 800 B.C. to A.D.
1600 must also add new facets to our picture of Ptolemy and of his work.
Almost as a stocktaking of Ptolemy, the 1970s saw the publication of three
monographic writings on his astronomy, *viz, *O. Neugebauer's authoritative
account of the contents of the *Almagest *in its context of the mathematical
side of the rest of ancient astronomy,^{1 }O.
Pedersen's *Almagest *companion volume designed to guide also the
student of Latin astronomy up to the Renaissance,^{2}
and R. R. Newton's book with a scientist's announcement of zero reliability
for the observations Ptolemy claims to have made himself as well as for
many of the observations that he attributes to other astronomers. All of
the three works are indispensable on my shelf with standard books of reference,
in the case of Newton's book for two reasons: first because of its highly
acute and reliable analysis of the observational and theoretical data in
the *Almagest, *and of their mutual interdependence, and second because
I disagree completely with the author in his judgement of Ptolemy as a
deliberate criminal in his activity as an astronomer.

In a series of publications
from the period 1969-76 Newton has investigated the non-gravitational accelerations
within the solar system. To this end he compared positions of the heavenly
bodies, as reported in Ancient and Medieval observations, with "gravitational"
positions drawn from calculations back in time with the most accurate modern
ephemeris programs. On this plan of scientific research he had to evaluate
the reliability of the old observations, as far as possible on *a priori
*considerations of their historical context alone. Both from such evaluations
and from the lack of coherence with earlier and later observations, Newton
soon came to distrust the authenticity of the observational data in the
*Almagest. *Therefore, you find spread in several of his publications
from the period 1973-76 chapters and sections devoted to documentation
of the thesis that all of Ptolemy's claimed observations that he used and
that can be tested prove to be fraudulent. In the book under review he
collects, in a single cohesive source, all of this material together with
further evidence to support the more far-reaching thesis that the fraudulent
data result from a deliberate plan, on Ptolemy's part, of hoodwinking his
fellow scientists and scholars. It is true that Ptolemy, time and again,
derived parameters known *a priori *from earlier astronomy by using
observations ostensibly fabricated to yield the result he wanted. Instances
of this procedure have been suspected, and in some cases documented, by
earlier astronomers and historians of astronomy. But only Newton's thorough
analysis reveals its full scope, demonstrating that it pervades the entire
structure of the *Almagest. *You may like or dislike Newton's habit
of accompanying his conclusions with statistical estimates of their confidence
level. In some cases equally probable premises for the statistics lead
to other levels, but never to invalidation of the partial conclusion in
question. However, I do not understand the sense of multiplying such confidence
levels for the partial conclusions into a combined×and triflingly low×probability
of Ptolemy's lack of criminal character.

To be sure, I do not find
Ptolemy guilty at all, for I do not imagine him striving to solve the particular
problem that Newton tacitly presupposes to be the ideal main concern of
Ptolemy's, *viz, *to initiate a new doctrine of astronomy based on
fresh data. On the contrary, I think that Ptolemy spent his efforts in
synthesizing the results of earlier astronomy rooted back into the work
of his Babylonian colleagues older than himself by a millennium. This includes
the necessity of preserving the continuity with basic parameters that had
worked well for centuries and had, therefore, deservedly grown canonical.
In current philosophical jargon×as coined by I. Lakatos×you may think of
these parameters as the 'hard core' of Babylonian as well as of Greek astronomy.
But while the Babylonians, by their arithmetic schemes, aimed at predicting
series of discrete events of a certain kind, say Full Moons and lunar eclipses,
the Greeks in their turn dramatically broadened the scope of astronomical
science. Their geometric models were designed to establish a general and
continuous correlation between any given date and the directions of sight
towards individual heavenly bodies, say, the Sun and the Moon. Clearly
this represents a theoretically 'progressive problem-shift'. But to ensure
that the new programme would yield virtually the same results for Full
Moons as the meritorious Babylonian schemes, the Greeks apparently chose
to build into the geometric models some of the basic Babylonian parameters.
In cases of conflict between the resulting calibration of the models and
contemporary observational data, produced by new observational techniques
the perfection of which could still be doubted, the right choice×'right'
in modern retrospect×may well have been anything but obvious. The fact
that Ptolemy, according to Newton's analysis, backed the wrong horse does
not make for a crime. The crime thesis provoked me to spend a couple of
years sorting out elements of the said 'hard core',^{3}
and that is why the present review has been unduly delayed.

Like Newton's earlier writings, this book with its huge accumulation of numerical data makes for a well-organized work of reference. Its thirteen chapters subdivided into ninety-six sections are carefully tabulated, and separate lists guide the reader to any of the sixty figures or of the thirty-nine tables. The text is set in unjustified typescript.

It is impossible to survey
here the wealth of arguments treasured up in the book, but as an appetizing
example let me refer to the particularly beautiful demonstration, in chap.
9, that the coordinates of the *Almagest *star catalogue stem from
an Hipparchian star list, now lost, but originally based on genuine observations
of star longitudes and latitudes. This does not clash with H. Vogt's well-known
analysis that the *Almagest *star coordinates do not originate specifically
in Hipparchus's "Commentary on Aratus and Eudoxus". The core of Newton's
argument hinges only on the statistical distribution of the fractional
parts of a degree in the coordinates. For the latitudes the distribution
in all probability reflects genuine observational data produced by an instrument
with integral degree markings only, or perhaps also with half-degree markings.
For the longitudes one may create a distribution with the very same characteristics,
but only after subtraction of 40'. This renders it probable that the *Almagest
*longitudes came about by the addition of 40' and, say, 2° to longitudes
observed by the same instrument as the latitudes.

University of Aarhus

KRISTIAN PEDER MOESGAARD

REFERENCES

1. O. Neugebauer,
*A history of Ancient mathematical astronomy *(New York, 1975).

2. O. Pedersen,
*A survey of the Almagest *(Odense, 1974).

3. K. P.
Moesgaard, "The Full Moon serpent: A foundation stone of Ancient astronomy",
*Centaurus, *xxiv (1980), 51-96.