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the emphasis had shifted somewhat, since this knowledge had to serve as an aid for the
transmission of the Christian doctrine and as an illustration of the wisdom of the Creator.
14.3.2 The Early Middle Ages in the Latin West
The
Book on Nature
, written around 613 by Isidorus Hispalensis of Sevilla (
c
. 560-636) for
the benefit of Sisebut, king of Visigothic Spain at Toledo, illustrates how this interpretation
and approach evolved and were transmitted into the early Middle Ages. Isidore (1960, 41,1)
explains why the sea does not grow as follows.
Bishop Clemens says that it is because the naturally salty water consumes the flow of fresh water which
it receives, in such a way that, however large the masses of water it receives, this salty element of the
sea nevertheless absorbs them totally. Add to this what the winds take away, and what the evaporation
and the heat of the sun absorbs. Finally, we see lakes and many ponds being consumed in a short time
by the blowing of the wind and the glowing of the sun. And then Solomon says: the streams return to
where they come from.
From which it can be understood that the sea does not increase also because, after being returned
to their sources through some conduits hidden in the deep, the waters flow back and run back along
the usual course through their rivers. But the sea was made purposely so it would receive the runs of
all rivers. While its depth is variable, the equality of its surface, however, cannot be discerned. As a
result, it is believed that it is called a plain, because its surface is even. But the physicists say that the
sea is higher than the land.
The title of Isidore's topic is nearly the same as that of Lucretius; also, as noted by Fontaine
(in Isidore, 1960) its outline is in many places similar to those of Aristotle, Lucretius, Pliny
and Aetius. So to organize his subject matter, Isidore must have had some doxographic
references at his disposal, or at least a monastery school manual of such material. But it is
striking how in this particular instance, Isidore's treatment on the origin of streams comes
closest to the opinion of Lucretius, quoted earlier. (Note that in the past Ecclesiastes has
often, evidently mistakenly, been attributed to Solomon). Less than a decade later around
620, Isidore (Isidorus, 1911; 13, 14) again gave a similar account in his topic
Etymologies
.
Therefore, the reason why the sea does not increase, although it receives all the streams and all the
springs, is as follows: in part, because its own magnitude does not feel the inflowing streams; further,
because the salty water consumes the fresh water flows; or because the clouds attract to themselves a
large portion of the water; also partly because the winds sweep it up, or partly because the sun dries
it up; finally, because after having percolated through some hidden openings of the earth and having
been returned to the head of the streams and to the springs, it runs back.
Isidore's writings rapidly spread all over Western Europe, and they had a huge impact.
Bede (
c
. 673-735), a Benedictine monk at Jarrow in England, who lived some 100 years
later, also wrote a book
On Nature
, which seems to be strongly inspired by Isidore's. His
section 40 on why the sea does not increase (Beda, 1843) is an almost literal summary
of Isidore's descriptions quoted above. Isidore's influence is also evident in the work of
Hrabanus Maurus (
c
. 776-856) of Mainz. Entitled variously
On Nature
or
On the Universe
,
it was written around 844, at the height of the Carolingian Renaissance. Intended as an aid
for preparing sermons, the text is replete with biblical references and Christian allegories
and Hrabanus comes across as a well-read author; however, for his explanation on why the
sea does not increase and on the origin of streams and springs, his main source was clearly
Isidore. His section on this topic (Rabanus Maurus, 1852; 11, 2) is taken nearly verbatim
from Isidore's (13, 14) quoted above.
These few examples show how by the end of the first millennium of the present era a
number of concepts of Greek natural philosophy had been propagated in Western Europe
