6

SIMPL. And who saith that I cannot draw other lines? why
may not I protract another line underneath, unto the point A,
that may be perpendicular to the rest?

SALV. You can doubtless, at one and the same point, make no
more than three right lines concurre, that constitute right angles
between themselves.

SAGR. I see what Simplicius means, namely, that should the
said D A be prolonged downward, then by that means there might
be drawn two others, but they would be the same with the first
three, differing onely in this, that whereas now they onely touch,
then they would intersect, but not produce new dimensions.

In phyfical proofs
geometrical exact­
ness is not necessa­
ry.

SIMPL. I will not say that this your argument may not be con­
cludent; but yet this I say with Aristotle, that in things natural
it is not alwaies necessary, to bring Mathematical demonstrations.

SAGR. Grant that it were so where such proofs cannot be had,
yet if this case admit of them, why do not you use them? But it
would be good we spent no more words on this particular, for I
think that Salviatus will yield, both to Aristotle, and you, with­
out farther demonstration, that the World is a body, and perfect,
yea most perfect, as being the greatest work of God.

SALV. So really it is, therefore leaving the general contempla­

tion of the whole, let us descend to the consideration of its parts,
which Aristotle, in his first division, makes two, and they very diffe­
rent and almost contrary to one another; namely the Cœlestial,
and Elementary: that ingenerable, incorruptible, unalterable, un­
passible, &c. and this exposed to a continual alteration, mutati­
on, &c. Which difference, as from its original principle, he de­
rives from the diversity of local motions, and in this method he
proceeds.

Parts of the world
are two, according
to Aristotle, Cœle­
stial and Elemen­
tary contrary to
one another.

Leaving the sensible, if I may so speak, and retiring into the
Ideal world, he begins Architectonically to consider that nature
being the principle of motion, it followeth that natural bodies be

indued with local motion. Next he declares local motion to be
of three kinds, namely, circular, right, and mixt of right and cir­
cular: and the two first he calleth simple, for that of all lines the

circular, and right are onely simple; and here somewhat re­
straining himself, he defineth anew, of simple motions, one to be