5. THE RELATION OF SOUL AND BODY is clearly explained on the standpoint of the pre-established harmony. This relation, taking the premises of the monadology, might seem enigmatical. If no monad can work upon any other, how can the soul work upon the body to lead and move it? The enigma is solved by the pre-established harmony. While the body and soul, each one independently of the other, follows the laws of its being, the body working mechanically, and the soul pursuing ends, yet God has established such a concordant harmony of the two activities, such a parallelism of the two functions, that there is in fact a perfect unity for body and soul. There are, says Leibnitz, three views respecting the relation of body and soul. The first and most common supposes a reciprocal influence between the two, but such a view is untenable, because there can be no interchange between mind and matter. The second and occasional one (_cf._ § XXV. 1), brings about this interchange through the constant assistance of God, which is nothing more nor less than to make God a _Deus ex machina_. Hence the only solution for the problem is the hypothesis of a pre-established harmony. Leibnitz illustrates these three views in the following example. Let one conceive of two watches, whose hands ever accurately point to the same time. This agreement may be explained, first (the common view), by supposing an actual connection between the hands of each, so that the hand of the one watch might draw the hand of the other after it, or second (the occasional view), by conceiving of a watch-maker who continually keeps the hands alike, or in fine (the pre-established harmony), by ascribing to each a mechanism so exquisitely wrought that each one goes in perfect independence of the other, and at the same time in entire agreement with it.—That the soul is immortal (indestructible), follows at once from the doctrine of monads. There is no proper death. That which is called death is only the soul losing a part of the monads which compose the mechanism of its body, while the living element goes back to a condition similar to that in which it was before it came upon the theatre of the world.