PHILOSOPHY OF NATURE—LEIBNITZ’S IDEAS. 39 
that precede it. On the other hand, monads, in their in- 
finite diversities, succeed each other without a break from 
the most rudimentary to the most perfect ones. That pro- 
gression which we conceive of in the abstract quantities 
of mathematics exists among the real quantities of the 
world, which monads of every kind are. Force, life, will, 
are assigned in different proportions to all the degrees of » 
that immeasurable series—in the lower ones dull and imper- 
ceptible, in the higher ones potent and fruitful. The pas- 
sage of inferior monads to higher planes takes place gradu- 
ally through a thousand intermediate ones. The principles 
of bodies advance incessantly nearer to perfection, and do 
not differ essentially from those of the souls with which 
they are connected. Souls in their turn are numerous, and 
they too obey a law of progress. Thus there is a measure- 
less quantity of degrees of life, some more or less dominant 
over others, from the faint and dull activity of the atom of 
sand up to the sovereign power of absolute mind. Des- 
cartes had said that all the facts of Nature follow on in 
connection like geometric truths. Leibnitz shows us a yet 
deeper and more universal order in things. Every thing 
is proportioned, analogous, harmonious: all is held, is con- 
tinued, in unbroken interdependence. Thus we no longer 
recognize two distinct worlds, the natural and the spiritual 
one. Spiritual existences compose a part of one and the 
Same series with corporeal ones. The only differences be- 
tween them are differences of degree. 
The principle of the “sufficient reason” discloses to us 
the strict economy of things. Nothing occurs in Nature 
without a reason, but she is not wasteful of her reasons. 
She always chooses the shortest ways. Magnificent in 
effects, miserly in causes, she produces the greatest amount 
of work with the least amount of force. The reasons of 
the world, Leibnitz holds, are hidden in something extra- 
mundane, which differs from the interdependence of states, 
