e, and
not at all in the present, and in nature it resides among the things
{185} which are impossible. Whence from that which has been said, it
has no being, because where there is nothingness there would be a
vacuum.

[Sidenote: On Spirits]

106.

With regard to this matter, we have said on the previous page that the
definition of a spirit is a power united with a body, because it cannot
move of its own accord nor acquire any kind of motion. And if you say
that it moves itself, this cannot be within the elements, because if
the spirit is an incorporate quantity this quantity is a vacuum and the
vacuum does not exist in nature, and if it did exist it would be
immediately filled by the rushing in of the element in which the vacuum
was formed. So according to the definition of weight which runs:
"Gravity is an accidental power created by one element attracted to or
suspended in another," it follows that no element, weighing nothing in
its own element, can have weight in the element which is above it and
lighter than it; for instance, no one part of water has no more gravity
or lightness than any other part, but if you were to draw it up into
the air, it would acquire weight, and this weight cannot sustain itself
by itself; and it must therefore inevitably fall, and thus wherever
there is a vacuum in water it will fall in. The same thing would
happen with a spirit among the elements where it would continuously
generate a vacuum {186} in whatever element it might find itself, for
which reason it is inevitable that it would move in a constant flight
to the sky until it had quitted these elements.

[Sidenote: Has the Spirit a Body?]

107.

We have proved that a spirit cannot exist in the elements without a
body, nor move of itself by voluntary motion unless it be to rise
upwards. But now we will say that if such a spirit took a body made of
air it would inevitably melt into air, because if it remained united it
would be separated and fall and form a vacuum, as we have described
above. Therefore if it desired to remain in the air it is necessary
that it should blend with a quantity of air, and if it were united with
the air, two difficulties arise: that is, that it will rarefy that
portion of air with which it is mingled, and this rarefied air will fly
upwards and will not remain in the air which is heavier than itself;
and besides this the ethereal spiritual essence is disunited, and its
nature is changed,