The earth was mingled with the upper fire not to produce the stars,
but because fire has something terrestrial, as earth has something
igneous, as a result of all the bodies being contained within the
body of the universe. In short, every one of the elements includes
mixture of itself and of the other with which it participates. This
results from the interrelating community existing within the universe
(the "sympathy"). So each element, without combining with any other,
borrows some of its properties. For example, water participates in the
fluidity of the air, without however mingling therewith; so the earth
does not possess the fire, but derives its brightness from it. On
the other hand, a mixture would render all properties common to both
elements, confounding them together,[218] and would not limit itself
to merely approximating earth and fire, that is, a certain solidity
with a certain density. On this subject we can invoke the authority of
(Plato[219]), "The divinity lit this light in the second circle above
the earth," thereby referring to the sun, which he elsewhere calls "the
most brilliant star."
By these words he hinders us from admitting that the sun is anything
else than fire. He also indicates that fire has no quality other than
light, which he considers as distinct from flame, and as possessing
only a gentle heat. This light is a body. From it emanates another
being that we, by verbal similarity, also call light, and which we
acknowledge to be incorporeal. This second kind of light derives from
the former, being its flower and brightness, and constitutes the
essentially white (that is, brilliant) body (of lightning, or comets).
(Unfortunately, however), the word "terrestrial" (which designates the
element allied to the fire, as we have said above), we are wont to
regard unfavorably because Plato makes the earth consist of solidity,
while we speak of the earth as a unity, though (Plato) distinguishes
several qualities within this element.