The philosophical and mathematical commentaries of Proclus on the first book of Euclid's elements (Vol. 1 of 2) : $b To which are added, A history of the restoration of Platonic theology, by the latter Platonists: And a translation from the Greek of Proclus's Theological elements
Plato · en
Previous to the discussion of the first question, it is necessary to
know that infinite intermediates cannot intervene between two finite
terms in an ascending and descending series of predications. I call the
series ascending which rises to universals; but descending, which, by
a contrary process, stops at particulars. Thus, if any one admits that
_a_ is some first predicate, and _g_ some ultimate subject,
and should contend, that between these terms there may be infinite
mediums, he contradicts himself; since he who begins from _a_ in a
descending progression, will never, by this means, arrive at _g_;
and he who departs from _g_ in an ascending series, can never
finally rise to _a_. So that the extremes can be no longer finite,
as the hypothesis admitted. Indeed, the absurdity of such a supposition
is the same as to contend that between one and ten, an infinity of
numbers may exist; which is evidently impossible, because the discrete
nature of numbers excludes their actual existence in infinitum,
between any finite limits; since they can only become infinite from
their actual existence and precedence, and not from any dormant power
or capacity they possess: for between any two given numbers there is
nothing similar to number in capacity, which can ever become number
in energy; as in quantity continuous between any two points there are
always parts in capacity, which, whenever a proper agent is at hand,
become immediately actual. In like manner, he who admits the terms
finite, but believes that the mediums are infinite, asserts what is
impossible, since these logical predications are of the same discrete
nature with numbers themselves. Thus all the predicates which can exist
between Socrates and substance, must exist actually, or not at all; for
surely between these two terms, or periods, no predicate in capacity
can ever be supposed to subsist. If it be urged, that the capacity of
receiving these predicates exists between Socrates and substance, still
we reply, it is not that kind of capacity in which these predicates can
retain the most shadowy existence; out of which they can ever be called
forth into energy, as from some latent retreat; or into which they
can finally retire, when energy is no more. And hence we conclude it
impossible that infinite mediums can exist between any finite terms.