These then are the principal factors which determine the next birth of the
man. First acts the great law of evolution, and its tendency is to press
the man into that position in which he can most easily develop the
qualities which he most needs. For the purposes of the general scheme,
humanity is divided into great races, called root-races, which rule and
occupy the world successively. The great Aryan or Indo-Caucasian race,
which at the present moment includes the most advanced of Earth's
inhabitants, is one of these. That which came before it in the order of
evolution was the Mongolian race, usually called in Theosophical books
Atlantean because the continent from which it ruled the world lay where now
roll the waters of the Atlantic ocean. Before that came the Negroid race,
some of whose descendants still exist, though by this time much mingled
with offshoots of later races. From each of these great root-races there
are many offshoots which we call sub-races--such, for example, as the Roman
races or the Teutonic; and each of the sub-races in turn divides itself
into branch-races, such as the French and the Italians, the English and the
Germans.

These arrangements are made in order that for each ego there may be a wide
choice of varying conditions and surroundings. Each race is especially
adapted to develop within its people one or other of the qualities which
are needed in the course of evolution. In every nation there exist an
almost infinite number of diverse conditions, riches and poverty, a wide
field of opportunities or a total lack of them, facilities for development
or conditions under which development is difficult or well-nigh impossible.
Amidst all these infinite possibilities the pressure of the law of
evolution tends to guide the man to precisely those which best suit his
needs at the stage at which he happens to be.