8.  Let us now proceed to physical evil, which is treated of in Chapter IV.  Our famous author, having observed that metaphysical evil, or imperfection, springs from nothingness, concludes that physical evil, or discomfort, springs from matter, or rather from its movement; for without movement matter would be useless.  Moreover there must be contrariety in these movements; otherwise, if all went together in the same direction, there would be neither variety nor generation.  But the movements that cause [413] generations cause also corruptions, since from the variety of movements comes concussion between bodies, by which they are often dissipated and destroyed.  The Author of Nature however, in order to render bodies more enduring, distributed them into systems, those which we know being composed of luminous and opaque balls, in a manner so excellent and so fitting for the display of that which they contain, and for arousing wonder thereat, that we can conceive of nothing more beautiful.  But the crowning point of the work was the construction of animals, to the end that everywhere there should be creatures capable of cognition,

  Ne regio foret ulla suis animalibus orba.

Our sagacious author believes that the air and even the purest aether have their denizens as well as the water and the earth.  But supposing that there were places without animals, these places might have uses necessary for other places which are inhabited.  So for example the mountains, which render the surface of our globe unequal and sometimes desert and barren, are of use for the production of rivers and of winds; and we have no cause to complain of sands and marshes, since there are so many places still remaining to be cultivated.  Moreover, it must not be supposed that all is made for man alone:  and the author is persuaded that there are not only pure spirits but also immortal animals of a nature akin to these spirits, that is, animals whose souls are united to an ethereal and incorruptible matter.  But it is not the same with animals whose body is terrestrial, composed of tubes and fluids which circulate therein, and whose motion is terminated by the breaking of the vessels.  Thence the author is led to believe that the immortality granted to Adam, if he had been obedient, would not have been an effect of his nature, but of the grace of God.

9.  Now it was necessary for the conservation of corruptible animals that they should have indications causing them to recognize a present danger, and giving them the inclination to avoid it.  That is why what is about to cause a great injury must beforehand cause pain such as may force the animal to efforts capable of repulsing or shunning the cause of this discomfort, and of forestalling a greater evil.  The dread of death helps also to cause its avoidance:  for it if were not so ugly and if the dissolution of continuity were not so painful, very often animals would take no precautions against perishing, or allowing the parts of their [414] body to perish, and the strongest would have difficulty in subsisting for a whole day.