The Extant Letters 21
- The size of the sun and the other heavenly bodies relative to us
is just as big as it appears.^13 But relative to itself it is either bigger or a
bit smaller than it is seen as being, or just the same size.^14 For in our
experience too fire-signals, when seen from a distance, are observed in
this way by our sense-perception. And every objection directed at this
portion [of our theory] will be easily dissolved if only one pays attention
to the clear facts, which we set out in our book On Nature. 92. The
risings and settings of the sun and the moon and the other heavenly bodies
could occur by kindling and extinguishing, as long as the circumstances in
both locales [i.e., east and west] are such as to produce the aforementioned
events; for none of the appearances testifies against this.they could
also be produced by the appearance [of these bodies] above the earth and
a subsequent blocking [by it]; for none of the appearances testifies against
this either. And it is not impossible that their motions come to pass
because of the rotation of the entire cosmos, or by its rest and their
rotation, produced by the necessity generated when they [first] rose, at
the beginning when the cosmos was [first] coming into being. [There is
probably a lacuna in the text here.] 93 .... by extreme heat produced
by a certain kind of distribution of the fire which constantly impinges
on the adjoining places.
The turnings of the sun and moon could come to pass because of the
obliquity of the heaven, which is compelled in this way at [certain] times;
similarly, it could also be because of the resistance in the air, or because
the fuel which regularly fits their requirements is burned up or is insuffi-
cient in quantity; or even because these heavenly bodies had forced on
them from the very beginning the sort of rotation which causes them to
have a kind of spiral motion. For all such possibilities and those like
them are in no way inconsistent with any of the clear facts, providing
one always in such detailed enquiries keeps a firm hold on what is possible
and can refer each of them to what is consistent with the phenomena,
not fearing the slavish technicalities of the astronomers. - The waning of the moon and its subsequent waxing could come
to pass by means of the turning of this body and just as well by means
of the changing shapes of the air, and again, also because of the interposi-
tion [of other bodies], and in all the ways which the phenomena in our
experience suggest for the explanation of this kind of thing-as long as
one is not so enamoured of the method of unique explanations as to - Scholiast: "This is also in book 11 of the On Nature; for, he says, if its size had been
reduced because of the distance, its brightness would have been even more reduced; for
there is no other distance more symmetrical with this [degree of brightness]." - Scholiast: "But not at the same time."